| CONSOLIDATED SCHEDULE OF INVESTMENTS - USD ($)
 | Sep. 30, 2023 | Sep. 30, 2022 | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 722,269,000 | [1] | $ 656,053,000 | [2] | 
| Fair Value |  | $ 704,815,000 | [1] | $ 649,615,000 | [2] | 
| Investment owned, percent of net assets |  | 172.50% | [1],[3],[4],[5],[6] | 205.90% | [2],[7],[8],[9],[10] | 
| Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 671,397,000 | [11] | $ 571,736,000 | [12] | 
| Fair Value |  | $ 663,544,000 | [11] | $ 574,811,000 | [12] | 
| Investment owned, percent of net assets |  | 162.40% | [3],[4],[5],[6],[11] | 182.20% | [7],[8],[9],[10],[12] | 
| Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 16,746,000 | [13] | $ 49,412,000 | [14] | 
| Fair Value |  | $ 10,421,000 | [13] | $ 39,091,000 | [14] | 
| Investment owned, percent of net assets |  | 2.60% | [3],[4],[5],[6],[13] | 12.40% | [7],[8],[9],[10],[14] | 
| Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 34,126,000 | [15] | $ 34,905,000 | [16] | 
| Fair Value |  | $ 30,850,000 | [15] | $ 35,713,000 | [16] | 
| Investment owned, percent of net assets |  | 7.50% | [3],[4],[5],[6],[15] | 11.30% | [7],[8],[9],[10],[16] | 
| Secured first lien debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 529,376,000 |  | $ 475,806,000 |  | 
| Fair Value |  | 510,701,000 |  | 463,858,000 |  | 
| Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 507,116,000 | [11] | 420,857,000 | [12] | 
| Fair Value |  | $ 491,686,000 | [11] | $ 413,631,000 | [12] | 
| Investment owned, percent of net assets |  | 120.30% | [3],[4],[5],[6],[11] | 131.20% | [7],[8],[9],[10],[12] | 
| Secured first lien debt | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [14] |  |  | $ 39,306,000 |  | 
| Fair Value |  | $ 2,895,000 |  | $ 34,804,000 | [14] | 
| Investment owned, percent of net assets |  | 0.70% | [3],[4],[5],[6],[13] | 11.00% | [7],[8],[9],[10],[14] | 
| Secured first lien debt | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [15] | $ 16,120,000 |  |  |  | 
| Fair Value |  | $ 16,120,000 | [15] | $ 15,423,000 |  | 
| Investment owned, percent of net assets |  | 3.90% | [3],[4],[5],[6],[15] | 4.90% | [7],[8],[9],[10],[16] | 
| Secured second lien debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 130,252,000 |  | $ 118,949,000 |  | 
| Fair Value |  | $ 127,854,000 |  | 115,928,000 |  | 
| Secured second lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [12] |  |  | 111,284,000 |  | 
| Fair Value | [12] |  |  | $ 108,263,000 |  | 
| Investment owned, percent of net assets |  | 29.50% | [3],[4],[5],[6],[11] | 34.30% | [7],[8],[9],[10],[12] | 
| Secured second lien debt | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 1.80% | [3],[4],[5],[6],[15] | 2.40% | [7],[8],[9],[10],[16] | 
| Preferred equity |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 35,617,000 |  | $ 34,505,000 |  | 
| Fair Value |  | 26,855,000 |  | 27,046,000 |  | 
| Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 23,061,000 | [11] | 21,949,000 | [12] | 
| Fair Value |  | $ 21,733,000 | [11] | $ 17,719,000 | [12] | 
| Investment owned, percent of net assets |  | 5.30% | [3],[4],[5],[6],[11] | 5.60% | [7],[8],[9],[10],[12] | 
| Preferred equity | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 9,806,000 | [13] | $ 9,806,000 | [14] | 
| Fair Value |  | $ 5,122,000 | [13] | $ 3,640,000 | [14] | 
| Investment owned, percent of net assets |  | 1.30% | [3],[4],[5],[6],[13] | 1.20% | [7],[8],[9],[10],[14] | 
| Preferred equity | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[15] | 1.80% | [7],[8],[9],[10],[16] | 
| Common equity/equivalents |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 26,826,000 |  | $ 26,500,000 |  | 
| Fair Value |  | 39,381,000 |  | 42,728,000 |  | 
| Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 18,195,000 | [11] | 17,448,000 | [12] | 
| Fair Value |  | $ 29,672,000 | [11] | $ 35,143,000 | [12] | 
| Investment owned, percent of net assets |  | 7.30% | [3],[4],[5],[6],[11] | 11.10% | [7],[8],[9],[10],[12] | 
| Common equity/equivalents | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [14] |  |  | $ 300,000 |  | 
| Fair Value | [14] |  |  | $ 647,000 |  | 
| Investment owned, percent of net assets |  | 0.60% | [3],[4],[5],[6],[13] | 0.20% | [7],[8],[9],[10],[14] | 
| Common equity/equivalents | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 7,831,000 | [15] | $ 8,752,000 | [16] | 
| Fair Value |  | $ 7,305,000 | [15] | $ 6,938,000 | [16] | 
| Investment owned, percent of net assets |  | 1.80% | [3],[4],[5],[6],[15] | 2.20% | [7],[8],[9],[10],[16] | 
| Unsecured debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 198,000 |  | $ 293,000 |  | 
| Fair Value |  | $ 24,000 |  | $ 55,000 |  | 
| Unsecured debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Unsecured debt | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% |  | 0.00% | [7],[8],[9],[10],[16] | 
| Aerospace and Defense |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 97,836,000 |  | $ 88,649,000 |  | 
| Aerospace and Defense | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 79,197,000 | [11] | 74,112,000 | [12] | 
| Fair Value |  | $ 78,720,000 | [11] | $ 73,898,000 | [12] | 
| Investment owned, percent of net assets |  | 19.30% | [3],[4],[5],[6],[11] | 23.40% | [7],[8],[9],[10],[12] | 
| Aerospace and Defense | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 5,283,000 | [11] | $ 5,283,000 | [12] | 
| Fair Value |  | $ 19,116,000 | [11] | $ 14,751,000 | [12] | 
| Investment owned, percent of net assets |  | 4.70% | [3],[4],[5],[6],[11] | 4.70% | [7],[8],[9],[10],[12] | 
| Beverage, Food, and Tobacco |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 78,788,000 |  | $ 64,283,000 |  | 
| Beverage, Food, and Tobacco | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 75,063,000 | [11] | 59,730,000 | [12] | 
| Fair Value |  | $ 72,868,000 | [11] | $ 58,971,000 | [12] | 
| Investment owned, percent of net assets |  | 17.80% | [3],[4],[5],[6],[11] | 18.70% | [7],[8],[9],[10],[12] | 
| Beverage, Food, and Tobacco | Secured second lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.60% | [3],[4],[5],[6],[11] | 1.00% | [7],[8],[9],[10],[12] | 
| Beverage, Food, and Tobacco | Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Beverage, Food, and Tobacco | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 1,750,000 | [11] | $ 1,750,000 | [12] | 
| Fair Value |  | $ 3,284,000 | [11] | $ 2,172,000 | [12] | 
| Investment owned, percent of net assets |  | 0.80% | [3],[4],[5],[6],[11] | 0.70% | [7],[8],[9],[10],[12] | 
| Buildings and Real Estate | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 2,275,000 | [11] | $ 1,700,000 | [12] | 
| Fair Value |  | $ 2,150,000 | [11] | $ 1,654,000 | [12] | 
| Investment owned, percent of net assets |  | 0.50% | [3],[4],[5],[6],[11] | 0.50% | [7],[8],[9],[10],[12] | 
| Buildings and Real Estate | Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.10% | [3],[4],[5],[6],[11] | 0.20% | [7],[8],[9],[10],[12] | 
| Buildings and Real Estate | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Manufacturing |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 158,061,000 |  | $ 114,105,000 |  | 
| Diversified/Conglomerate Manufacturing | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 117,832,000 | [11] | 70,815,000 | [12] | 
| Fair Value |  | $ 113,878,000 | [11] | $ 70,117,000 | [12] | 
| Investment owned, percent of net assets |  | 27.90% | [3],[4],[5],[6],[11] | 22.30% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Manufacturing | Secured first lien debt | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.70% |  | 0.80% | [7],[8],[9],[10],[14] | 
| Diversified/Conglomerate Manufacturing | Secured first lien debt | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.90% | [3],[4],[5],[6],[15] | 1.00% | [7],[8],[9],[10],[16] | 
| Diversified/Conglomerate Manufacturing | Secured second lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 36,868,000 | [11] | $ 34,829,000 | [12] | 
| Fair Value |  | $ 36,136,000 | [11] | $ 34,051,000 | [12] | 
| Investment owned, percent of net assets |  | 8.90% | [3],[4],[5],[6],[11] | 10.80% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Manufacturing | Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.30% | [3],[4],[5],[6],[11] | 0.80% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Manufacturing | Preferred equity | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[13] | 0.00% | [7],[8],[9],[10],[14] | 
| Diversified/Conglomerate Manufacturing | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [11] | $ 5,000,000 |  |  |  | 
| Fair Value | [11] | $ 0 |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 0.60% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Manufacturing | Common equity/equivalents | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [16] |  |  | $ 7,671,000 |  | 
| Fair Value |  | $ 0 |  | $ 0 | [16] | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[15] | 0.00% | [7],[8],[9],[10],[16] | 
| Diversified/Conglomerate Manufacturing | Unsecured debt | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% |  | 0.00% | [7],[8],[9],[10],[16] | 
| Diversified/Conglomerate Service |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 135,060,000 |  | $ 148,907,000 |  | 
| Diversified/Conglomerate Service | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 110,862,000 | [11] | 101,924,000 | [12] | 
| Fair Value |  | $ 104,293,000 | [11] | $ 97,884,000 | [12] | 
| Investment owned, percent of net assets |  | 25.50% | [3],[4],[5],[6],[11] | 31.10% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Service | Secured first lien debt | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [14] |  |  | $ 33,166,000 |  | 
| Fair Value |  | $ 0 |  | $ 32,254,000 | [14] | 
| Investment owned, percent of net assets |  | 0.00% |  | 10.20% | [7],[8],[9],[10],[14] | 
| Diversified/Conglomerate Service | Secured second lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 16,552,000 | [11] | $ 7,512,000 | [12] | 
| Fair Value |  | $ 16,465,000 | [11] | $ 7,265,000 | [12] | 
| Investment owned, percent of net assets |  | 4.00% | [3],[4],[5],[6],[11] | 2.30% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Service | Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 8,250,000 | [11] | $ 7,500,000 | [12] | 
| Fair Value |  | $ 9,654,000 | [11] | $ 8,151,000 | [12] | 
| Investment owned, percent of net assets |  | 2.40% | [3],[4],[5],[6],[11] | 2.60% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Service | Preferred equity | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 1.10% | [3],[4],[5],[6],[13] | 0.90% | [7],[8],[9],[10],[14] | 
| Diversified/Conglomerate Service | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.10% | [3],[4],[5],[6],[11] | 0.10% | [7],[8],[9],[10],[12] | 
| Diversified/Conglomerate Service | Unsecured debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% |  | 0.00% | [7],[8],[9],[10],[12] | 
| Healthcare, Education, and Childcare |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 146,438,000 |  | $ 136,401,000 |  | 
| Healthcare, Education, and Childcare | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 108,759,000 | [11] | 99,644,000 | [12] | 
| Fair Value |  | $ 108,185,000 | [11] | $ 98,881,000 | [12] | 
| Investment owned, percent of net assets |  | 26.50% | [3],[4],[5],[6],[11] | 31.30% | [7],[8],[9],[10],[12] | 
| Healthcare, Education, and Childcare | Secured second lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 7.10% | [3],[4],[5],[6],[11] | 9.10% | [7],[8],[9],[10],[12] | 
| Healthcare, Education, and Childcare | Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.80% | [3],[4],[5],[6],[11] | 0.30% | [7],[8],[9],[10],[12] | 
| Healthcare, Education, and Childcare | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 2,786,000 | [11] | $ 2,009,000 | [12] | 
| Fair Value |  | $ 6,002,000 | [11] | $ 7,775,000 | [12] | 
| Investment owned, percent of net assets |  | 1.50% | [3],[4],[5],[6],[11] | 2.50% | [7],[8],[9],[10],[12] | 
| Machinery |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 6,411,000 |  | $ 9,562,000 |  | 
| Machinery | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 5,928,000 | [11] | 5,625,000 | [12] | 
| Fair Value |  | $ 5,724,000 | [11] | $ 5,350,000 | [12] | 
| Investment owned, percent of net assets |  | 1.40% | [3],[4],[5],[6],[11] | 1.70% | [7],[8],[9],[10],[12] | 
| Machinery | Secured second lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets | [7],[8],[9],[10],[12] |  |  | 0.20% |  | 
| Machinery | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.10% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Machinery | Common equity/equivalents | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.10% | [3],[4],[5],[6],[15] | 1.10% | [7],[8],[9],[10],[16] | 
| Telecommunications |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 5,868,000 |  | $ 10,088,000 |  | 
| Telecommunications | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | 7,200,000 | [11] | 7,200,000 | [12] | 
| Fair Value |  | $ 5,868,000 | [11] | $ 6,876,000 | [12] | 
| Investment owned, percent of net assets |  | 1.40% | [3],[4],[5],[6],[11] | 2.20% | [7],[8],[9],[10],[12] | 
| Telecommunications | Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [12] |  |  | $ 2,813,000 |  | 
| Fair Value | [12] |  |  | $ 3,187,000 |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 1.10% | [7],[8],[9],[10],[12] | 
| Telecommunications | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Automobile |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 27,571,000 |  | $ 20,144,000 |  | 
| Automobile | Secured second lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [11] | 16,053,000 |  |  |  | 
| Fair Value | [11] | $ 15,675,000 |  |  |  | 
| Investment owned, percent of net assets |  | 3.80% | [3],[4],[5],[6],[11] | 3.50% | [7],[8],[9],[10],[12] | 
| Automobile | Secured second lien debt | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 1.80% |  | 2.40% | [7],[8],[9],[10],[16] | 
| Automobile | Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Automobile | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.10% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Automobile | Common equity/equivalents | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 1.00% | [3],[4],[5],[6],[15] | 0.40% | [7],[8],[9],[10],[16] | 
| Oil and Gas |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Fair Value |  | $ 27,830,000 |  | $ 25,373,000 |  | 
| Oil and Gas | Secured second lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [11] | 122,827,000 |  |  |  | 
| Fair Value | [11] | $ 120,429,000 |  |  |  | 
| Investment owned, percent of net assets |  | 5.10% | [3],[4],[5],[6],[11] | 7.40% | [7],[8],[9],[10],[12] | 
| Oil and Gas | Preferred equity | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 6,838,000 | [11] | $ 6,982,000 | [12] | 
| Fair Value |  | $ 6,826,000 | [11] | $ 2,028,000 | [12] | 
| Investment owned, percent of net assets |  | 1.70% | [3],[4],[5],[6],[11] | 0.60% | [7],[8],[9],[10],[12] | 
| Oil and Gas | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 499,000 | [11] | $ 499,000 | [12] | 
| Fair Value |  | $ 146,000 | [11] | $ 50,000 | [12] | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Personal and Non-Durable Consumer Products (Manufacturing Only) | Secured first lien debt | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost |  | $ 11,293,000 | [15] | $ 11,393,000 | [16] | 
| Fair Value |  | $ 11,293,000 | [15] | $ 11,393,000 | [16] | 
| Investment owned, percent of net assets |  | 2.80% | [3],[4],[5],[6],[15] | 3.60% | [7],[8],[9],[10],[16] | 
| Personal and Non-Durable Consumer Products (Manufacturing Only) | Preferred equity | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.20% | [3],[4],[5],[6],[13] | 0.30% | [7],[8],[9],[10],[14] | 
| Personal and Non-Durable Consumer Products (Manufacturing Only) | Preferred equity | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% |  | 1.80% | [7],[8],[9],[10],[16] | 
| Personal and Non-Durable Consumer Products (Manufacturing Only) | Common equity/equivalents | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.00% | [3],[4],[5],[6],[11] | 0.00% | [7],[8],[9],[10],[12] | 
| Personal and Non-Durable Consumer Products (Manufacturing Only) | Common equity/equivalents | Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.60% |  | 0.20% | [7],[8],[9],[10],[14] | 
| Printing and Publishing | Secured first lien debt | Non-Control/Non-Affiliate investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets | [7],[8],[9],[10],[12] |  |  | 0.00% |  | 
| Printing and Publishing | Secured first lien debt | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Cost | [16] |  |  | $ 15,643,000 |  | 
| Fair Value | [16] |  |  | $ 15,423,000 |  | 
| Investment owned, percent of net assets |  | 0.20% | [3],[4],[5],[6],[15] | 0.30% | [7],[8],[9],[10],[16] | 
| Printing and Publishing | Common equity/equivalents | Control investments |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Investment owned, percent of net assets |  | 0.70% | [3],[4],[5],[6],[15] | 0.70% |  | 
| Investment, Identifier [Axis]: Leeds Novamark Capital I, L.P. – Limited Partnership Interest |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Units | [17],[18],[19],[20],[21] |  |  | 3.50% |  | 
| Cost | [18],[20],[21] |  |  | $ 1,223,000 |  | 
| Fair Value | [18],[20],[21] |  |  | 6,397,000 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[18],[20],[21] |  |  | $ 843,000 |  | 
| Investment, Identifier [Axis]: Antenna Research Associates, Inc. – Common Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [17],[19],[20],[22] |  |  | 4,283 |  | 
| Cost | [20],[22] |  |  | $ 4,283,000 |  | 
| Fair Value | [20],[22] |  |  | $ 13,734,000 |  | 
| Investment, Identifier [Axis]: Engineering Manufacturing Technologies, LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [17],[19],[20],[22] |  |  | 6,000 |  | 
| Cost | [20],[22] |  |  | $ 3,000,000 |  | 
| Fair Value | [20],[22] |  |  | $ 1,773,000 |  | 
| Investment, Identifier [Axis]: Ohio Armor Holdings, LLC – Common Equity |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [17],[19],[20],[22] |  |  | 100 |  | 
| Cost | [20],[22] |  |  | $ 1,000,000 |  | 
| Fair Value | [20],[22] |  |  | 1,017,000 |  | 
| Investment, Identifier [Axis]: 8th Avenue Food & Provisions, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | $ 3,683,000 | [23],[24],[25] | 3,682,000 | [17],[19],[26] | 
| Cost |  | 3,683,000 | [23] | 3,698,000 | [26] | 
| Fair Value |  | 2,495,000 | [23] | 3,020,000 | [26] | 
| Investment, Identifier [Axis]: ALS Education, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 | [24],[25],[27] | 0 | [17],[19],[28] | 
| Cost |  | 0 | [27] | 0 | [28] | 
| Fair Value |  | 0 | [27] | 0 | [28] | 
| Line of credit facility, available |  | 3,000,000 | [3],[4],[5],[6],[27] | 3,000,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: ALS Education, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 18,700,000 | [24],[25],[27] | 19,690,000 | [17],[19],[28] | 
| Cost |  | 18,700,000 | [27] | 19,690,000 | [28] | 
| Fair Value |  | $ 18,700,000 | [27] | 19,468,000 | [28] | 
| Investment, Identifier [Axis]: Antenna Research Associates, Inc. – Common Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [24],[25],[29],[30] | 4,283,000 |  |  |  | 
| Cost | [29],[30] | $ 4,283,000 |  |  |  | 
| Fair Value | [29],[30] | 18,436,000 |  |  |  | 
| Investment, Identifier [Axis]: Antenna Research Associates, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 30,048,000 | [24],[25],[29] | 21,973,000 | [17],[19],[22] | 
| Cost |  | 30,048,000 | [29] | 21,973,000 | [22] | 
| Fair Value |  | $ 30,048,000 | [29] | $ 21,973,000 | [22] | 
| Investment, Identifier [Axis]: Arc Drilling Holdings LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 15,000,000 | [24],[25],[29],[30] | 15,000 | [17],[19],[20],[22] | 
| Cost |  | $ 1,500,000 | [29],[30] | $ 1,500,000 | [20],[22] | 
| Fair Value |  | 403,000 | [29],[30] | 0 | [20],[22] | 
| Investment, Identifier [Axis]: Arc Drilling Holdings LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 | [24],[25],[27] | 0 | [17],[19],[28] | 
| Cost |  | 0 | [27] | 0 | [28] | 
| Fair Value |  | 0 | [27] | 0 | [28] | 
| Line of credit facility, available |  | 1,000,000 | [3],[4],[5],[6],[27] | 1,000,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Arc Drilling Holdings LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 5,928,000 |  |  |  | 
| Cost | [27] | 5,928,000 |  |  |  | 
| Fair Value | [27] | 5,724,000 |  |  |  | 
| Investment, Identifier [Axis]: Arc Drilling Holdings LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 5,625,000 |  | 
| Cost | [28] |  |  | 5,625,000 |  | 
| Fair Value | [28] |  |  | 5,350,000 |  | 
| Investment, Identifier [Axis]: Axios Industrial Group, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 11,550,000 | [24],[25],[27] | 9,000,000 | [17],[19],[28],[31] | 
| Cost |  | 11,519,000 | [27] | 9,000,000 | [28],[31] | 
| Fair Value |  | 11,291,000 | [27] | 8,741,000 | [28],[31] | 
| Investment, Identifier [Axis]: Axios Industrial Group, LLC– Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[31] |  |  | 3,000,000 |  | 
| Cost | [28],[31] |  |  | 3,000,000 |  | 
| Fair Value | [28],[31] |  |  | 2,914,000 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28],[31] |  |  | $ 5,000,000 |  | 
| Investment, Identifier [Axis]: B+T Group Acquisition, Inc. – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[32] | 1,200,000 |  |  |  | 
| Cost | [27],[32] | 1,200,000 |  |  |  | 
| Fair Value | [27],[32] | 978,000 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[27],[32] | 0 |  |  |  | 
| Investment, Identifier [Axis]: B+T Group Acquisition, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[32] | 6,000,000 |  |  |  | 
| Cost | [27],[32] | 6,000,000 |  |  |  | 
| Fair Value | [27],[32] | $ 4,890,000 |  |  |  | 
| Investment, Identifier [Axis]: B+T Group Acquisition, Inc.(S) – Common Stock Warrant |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Units |  | 1.50% | [24],[25],[29],[30],[32] | 1.50% | [17],[19],[20],[22],[33] | 
| Cost |  | $ 0 | [29],[30],[32] | $ 0 | [20],[22],[33] | 
| Fair Value |  | $ 0 | [29],[30],[32] | 25,000 | [20],[22],[33] | 
| Investment, Identifier [Axis]: B+T Group Acquisition, Inc.(S) – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[33] |  |  | 1,200,000 |  | 
| Cost | [28],[33] |  |  | 1,200,000 |  | 
| Fair Value | [28],[33] |  |  | 1,146,000 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28],[33] |  |  | $ 0 |  | 
| Investment, Identifier [Axis]: B+T Group Acquisition, Inc.(S) – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 6,130,000 | [24],[25],[29],[30],[32] | 6,130 | [17],[19],[20],[22],[33] | 
| Cost |  | $ 2,024,000 | [29],[30],[32] | $ 2,024,000 | [20],[22],[33] | 
| Fair Value |  | 0 | [29],[30],[32] | 2,718,000 | [20],[22],[33] | 
| Investment, Identifier [Axis]: B+T Group Acquisition, Inc.(S) – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[33] |  |  | 6,000,000 |  | 
| Cost | [28],[33] |  |  | 6,000,000 |  | 
| Fair Value | [28],[33] |  |  | 5,730,000 |  | 
| Investment, Identifier [Axis]: CHA Holdings, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [23],[24],[25],[34] | 3,000,000 |  |  |  | 
| Cost | [23],[34] | 2,974,000 |  |  |  | 
| Fair Value | [23],[34] | 2,820,000 |  |  |  | 
| Investment, Identifier [Axis]: CHA Holdings, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[26],[35] |  |  | 3,000,000 |  | 
| Cost | [26],[35] |  |  | 2,967,000 |  | 
| Fair Value | [26],[35] |  |  | 2,700,000 |  | 
| Investment, Identifier [Axis]: CPM Holdings, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[26] |  |  | 798,000 |  | 
| Cost | [26] |  |  | 798,000 |  | 
| Fair Value | [26] |  |  | 758,000 |  | 
| Investment, Identifier [Axis]: Cafe Zupas – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 0 |  |  |  | 
| Cost | [27] | 0 |  |  |  | 
| Fair Value | [27] | 0 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[27] | 1,500,000 |  |  |  | 
| Investment, Identifier [Axis]: Café Zupas – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 7,970,000 | [24],[25],[27] | 1,970,000 | [17],[19],[28] | 
| Cost |  | 7,970,000 | [27] | 1,970,000 | [28] | 
| Fair Value |  | 7,850,000 | [27] | 1,958,000 | [28] | 
| Line of credit facility, available |  | 2,070,000 | [3],[4],[5],[6],[27] | 0 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Café Zupas – Line of Credit, |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 0 |  | 
| Cost | [28] |  |  | 0 |  | 
| Fair Value | [28] |  |  | 0 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28] |  |  | 4,000,000 |  | 
| Investment, Identifier [Axis]: Café Zupas – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 23,460,000 | [24],[25],[27] | 23,460,000 | [17],[19],[28] | 
| Cost |  | 23,460,000 | [27] | 23,460,000 | [28] | 
| Fair Value |  | $ 23,108,000 | [27] | $ 23,313,000 | [28] | 
| Investment, Identifier [Axis]: Canopy Safety Brands, LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 1,170,370,000 | [24],[25],[29],[30] | 800,000 | [17],[19],[20],[22] | 
| Cost |  | $ 800,000 | [29],[30] | $ 300,000 | [20],[22] | 
| Fair Value |  | $ 2,404,000 | [29],[30] | $ 647,000 | [20],[22] | 
| Investment, Identifier [Axis]: Canopy Safety Brands, LLC – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 500,000,000 | [24],[25],[29],[30] | 500,000 | [17],[19],[20],[22] | 
| Cost |  | $ 500,000 | [29],[30] | $ 500,000 | [20],[22] | 
| Fair Value |  | $ 857,000 | [29],[30] | 798,000 | [20],[22] | 
| Investment, Identifier [Axis]: Canopy Safety Brands, LLC—Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 1,170,370 |  |  |  | 
| Fair Value |  | $ 2,404,000 |  | 647,000 |  | 
| Investment, Identifier [Axis]: Canopy Safety Brands, LLC—Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 500,000 |  |  |  | 
| Fair Value |  | $ 857,000 |  | 798,000 |  | 
| Investment, Identifier [Axis]: Chinese Yellow Pages Company – Line of Credit, |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[22],[36],[37] |  |  | 107,000 |  | 
| Cost | [22],[36],[37] |  |  | 107,000 |  | 
| Fair Value | [22],[36],[37] |  |  | 0 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[22],[36],[37] |  |  | $ 0 |  | 
| Investment, Identifier [Axis]: Circuitronics EMS Holdings LLC – Common Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [17],[19],[20],[22] |  |  | 921,000 |  | 
| Cost | [20],[22] |  |  | $ 921,000 |  | 
| Fair Value | [20],[22] |  |  | 0 |  | 
| Investment, Identifier [Axis]: Circuitronics EMS Holdings LLC—Common Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 0 |  |  |  | 
| Fair Value |  | $ 0 |  | 0 |  | 
| Investment, Identifier [Axis]: DKI Ventures, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[38] | 205,000 |  |  |  | 
| Cost | [27],[38] | 205,000 |  |  |  | 
| Fair Value | [27],[38] | 113,000 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[27],[38] | 170,000 |  |  |  | 
| Investment, Identifier [Axis]: DKI Ventures, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 5,915,000 | [24],[25],[27],[38] | 5,915,000 | [17],[19],[28] | 
| Cost |  | 5,915,000 | [27],[38] | 5,915,000 | [28] | 
| Fair Value |  | $ 3,253,000 | [27],[38] | $ 4,554,000 | [28] | 
| Investment, Identifier [Axis]: Defiance Integrated Technologies, Inc. – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 33,321,000 | [24],[25],[29],[30] | 33,321 | [17],[19],[20],[22] | 
| Cost |  | $ 580,000 | [29],[30] | $ 580,000 | [20],[22] | 
| Fair Value |  | 3,948,000 | [29],[30] | 1,147,000 | [20],[22] | 
| Investment, Identifier [Axis]: Defiance Integrated Technologies, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[29] | 7,425,000 |  |  |  | 
| Cost | [29] | 7,425,000 |  |  |  | 
| Fair Value | [29] | $ 7,425,000 |  |  |  | 
| Investment, Identifier [Axis]: Defiance Integrated Technologies, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[22] |  |  | 7,665,000 |  | 
| Cost | [22] |  |  | 7,665,000 |  | 
| Fair Value | [22] |  |  | 7,665,000 |  | 
| Investment, Identifier [Axis]: Defiance Integrated Technologies, Inc.—Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 33,321 |  |  |  | 
| Fair Value |  | $ 3,948,000 |  | 1,147,000 |  | 
| Investment, Identifier [Axis]: Defiance Integrated Technologies, Inc.—Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 7,425,000 |  |  |  | 
| Fair Value |  | 7,425,000 |  | 7,665,000 |  | 
| Investment, Identifier [Axis]: ENET Holdings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 22,289,000 | [24],[25],[27] | 24,360,000 | [17],[19],[28] | 
| Cost |  | 22,289,000 | [27] | 24,360,000 | [28] | 
| Fair Value |  | $ 21,397,000 | [27] | $ 23,142,000 | [28] | 
| Investment, Identifier [Axis]: Edge Adhesives Holdings, Inc. – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 5,466,000 | [24],[25],[29],[30],[32] | 5,466 | [17],[19],[20],[22],[33] | 
| Cost |  | $ 5,466,000 | [29],[30],[32] | $ 5,466,000 | [20],[22],[33] | 
| Fair Value |  | 0 | [29],[30],[32] | 0 | [20],[22],[33] | 
| Investment, Identifier [Axis]: Edge Adhesives Holdings, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[29],[32],[39] | 6,140,000 |  |  |  | 
| Cost | [29],[32],[39] | 6,140,000 |  |  |  | 
| Fair Value | [29],[32],[39] | $ 2,895,000 |  |  |  | 
| Investment, Identifier [Axis]: Edge Adhesives Holdings, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[22],[33] |  |  | 6,140,000 |  | 
| Cost | [22],[33] |  |  | 6,140,000 |  | 
| Fair Value | [22],[33] |  |  | 2,550,000 |  | 
| Investment, Identifier [Axis]: Edge Adhesives Holdings, Inc.—Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 5,466 |  |  |  | 
| Fair Value |  | $ 0 |  | 0 |  | 
| Investment, Identifier [Axis]: Edge Adhesives Holdings, Inc.—Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 6,140,000 |  |  |  | 
| Fair Value |  | 2,895,000 |  | 2,550,000 |  | 
| Investment, Identifier [Axis]: Eegee’s LLC – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 3,000,000 | [24],[25],[27] | 3,000,000 | [17],[19],[28] | 
| Cost |  | 3,000,000 | [27] | 3,000,000 | [28] | 
| Fair Value |  | 2,865,000 | [27] | 2,910,000 | [28] | 
| Line of credit facility, available |  | 4,500,000 | [3],[4],[5],[6],[27] | 4,500,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Eegee’s LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 | [24],[25],[27] | 0 | [17],[19],[28] | 
| Cost |  | 0 | [27] | 0 | [28] | 
| Fair Value |  | 0 | [27] | 0 | [28] | 
| Line of credit facility, available |  | 1,000,000 | [3],[4],[5],[6],[27] | 1,000,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Eegee’s LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 17,000,000 |  |  |  | 
| Cost | [27] | 17,000,000 |  |  |  | 
| Fair Value | [27] | $ 16,235,000 |  |  |  | 
| Investment, Identifier [Axis]: Eegee’s LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 17,000,000 |  | 
| Cost | [28] |  |  | 17,000,000 |  | 
| Fair Value | [28] |  |  | 16,490,000 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 5,023,000 |  | 
| Cost | [28] |  |  | 5,023,000 |  | 
| Fair Value | [28] |  |  | 4,885,000 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28] |  |  | 0 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 0 |  | 
| Cost | [28] |  |  | 0 |  | 
| Fair Value | [28] |  |  | 0 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28] |  |  | $ 3,000,000 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 3,840,000,000 | [24],[25],[29],[30] | 3,840,000 | [17],[19],[20],[22],[33] | 
| Cost |  | $ 3,840,000 | [29],[30] | $ 3,840,000 | [20],[22],[33] | 
| Fair Value |  | 4,265,000 | [29],[30] | 2,842,000 | [20],[22],[33] | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC – Term Debt 1 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 23,611,000 |  | 
| Cost | [28] |  |  | 23,611,000 |  | 
| Fair Value | [28] |  |  | 22,962,000 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC – Term Debt 2 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 4,532,000 |  | 
| Cost | [28] |  |  | 4,532,000 |  | 
| Fair Value | [28] |  |  | 4,407,000 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC—Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 |  |  |  | 
| Fair Value |  | 0 |  | 4,885,000 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC—Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 |  |  |  | 
| Fair Value |  | $ 0 |  | 0 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC—Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 3,840,000 |  |  |  | 
| Fair Value |  | $ 4,265,000 |  | 2,842,000 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC—Term Debt 1 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 |  |  |  | 
| Fair Value |  | 0 |  | 22,962,000 |  | 
| Investment, Identifier [Axis]: Encore Dredging Holdings, LLC—Term Debt 2 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 |  |  |  | 
| Fair Value |  | $ 0 |  | 4,407,000 |  | 
| Investment, Identifier [Axis]: Engineering Manufacturing Technologies, LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [24],[25],[29],[30] | 6,000,000 |  |  |  | 
| Cost | [29],[30] | $ 3,000,000 |  |  |  | 
| Fair Value | [29],[30] | 0 |  |  |  | 
| Investment, Identifier [Axis]: Engineering Manufacturing Technologies, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 | [24],[25],[27] | 0 | [17],[19],[28] | 
| Cost |  | 0 | [27] | 0 | [28] | 
| Fair Value |  | 0 | [27] | 0 | [28] | 
| Line of credit facility, available |  | 3,000,000 | [3],[4],[5],[6],[27] | 3,000,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Engineering Manufacturing Technologies, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 21,500,000 | [24],[25],[27] | 22,500,000 | [17],[19],[28] | 
| Cost |  | 21,500,000 | [27] | 22,500,000 | [28] | 
| Fair Value |  | $ 19,726,000 | [27] | $ 22,134,000 | [28] | 
| Investment, Identifier [Axis]: FES Resources Holdings LLC – Common Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 6,233,000 | [24],[25],[29],[30] | 6,233 | [17],[19],[20],[22] | 
| Cost |  | $ 0 | [29],[30] | $ 0 | [20],[22] | 
| Fair Value |  | $ 0 | [29],[30] | $ 0 | [20],[22] | 
| Investment, Identifier [Axis]: FES Resources Holdings LLC – Preferred Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 6,350,000 | [24],[25],[29],[30] | 6,350 | [17],[19],[20],[22] | 
| Cost |  | $ 6,350,000 | [29],[30] | $ 6,350,000 | [20],[22] | 
| Fair Value |  | 4,508,000 | [29],[30] | 0 | [20],[22] | 
| Investment, Identifier [Axis]: Fix-It Group, LLC – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 6,911,000 | [24],[25],[27] | 0 | [17],[19],[28],[35] | 
| Cost |  | 6,911,000 | [27] | 0 | [28],[35] | 
| Fair Value |  | 6,894,000 | [27] | 0 | [28],[35] | 
| Line of credit facility, available |  | 0 | [3],[4],[5],[6],[27] | 10,000,000 | [7],[8],[9],[10],[28],[35] | 
| Investment, Identifier [Axis]: Fix-It Group, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 500,000 | [24],[25],[27] | 0 | [17],[19],[28],[35] | 
| Cost |  | 500,000 | [27] | 0 | [28],[35] | 
| Fair Value |  | 499,000 | [27] | 0 | [28],[35] | 
| Line of credit facility, available |  | 2,500,000 | [3],[4],[5],[6],[27] | 3,000,000 | [7],[8],[9],[10],[28],[35] | 
| Investment, Identifier [Axis]: Fix-It Group, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 12,200,000 | [24],[25],[27] | 10,000,000 | [17],[19],[28],[35] | 
| Cost |  | 12,200,000 | [27] | 10,000,000 | [28],[35] | 
| Fair Value |  | 12,170,000 | [27] | 9,950,000 | [28],[35] | 
| Investment, Identifier [Axis]: Frontier Financial Group Inc. – Convertible Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 198,000 | [24],[25],[29],[38] | 198,000 | [17],[19],[22],[40] | 
| Cost |  | 198,000 | [29],[38] | 198,000 | [22],[40] | 
| Fair Value |  | $ 24,000 | [29],[38] | $ 55,000 | [22],[40] | 
| Investment, Identifier [Axis]: Frontier Financial Group Inc. – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 766,000 | [24],[25],[29],[30] | 766 | [17],[19],[20],[22] | 
| Cost |  | $ 500,000 | [29],[30] | $ 500,000 | [20],[22] | 
| Fair Value |  | $ 0 | [29],[30] | $ 0 | [20],[22] | 
| Investment, Identifier [Axis]: Frontier Financial Group Inc. – Preferred Stock Warrant |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 168,000 | [24],[25],[29],[30] | 168 | [17],[19],[20],[22] | 
| Cost |  | $ 0 | [29],[30] | $ 0 | [20],[22] | 
| Fair Value |  | $ 0 | [29],[30] | $ 0 | [20],[22] | 
| Investment, Identifier [Axis]: Funko Acquisition Holdings, LLC(S) – Common Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 4,239,000 | [24],[25],[30],[32],[41] | 4,239 | [17],[19],[20],[33],[42] | 
| Cost |  | $ 22,000 | [30],[32],[41] | $ 22,000 | [20],[33],[42] | 
| Fair Value |  | $ 22,000 | [30],[32],[41] | $ 58,000 | [20],[33],[42] | 
| Investment, Identifier [Axis]: GFRC 360, LLC – Common Stock Warrants |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Units |  | 45.00% | [24],[25],[29],[30] | 45.00% | [17],[19],[20],[22] | 
| Cost |  | $ 0 | [29],[30] | $ 0 | [20],[22] | 
| Fair Value |  | 0 | [29],[30] | 0 | [20],[22] | 
| Investment, Identifier [Axis]: GFRC 360, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 1,275,000 | [24],[25],[27] | 700,000 | [17],[19],[28] | 
| Cost |  | 1,275,000 | [27] | 700,000 | [28] | 
| Fair Value |  | 1,205,000 | [27] | 681,000 | [28] | 
| Line of credit facility, available |  | $ 175,000 | [3],[4],[5],[6],[27] | $ 500,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: GFRC 360, LLC – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 1,000,000 | [24],[25],[29],[30] | 1,000 | [17],[19],[20],[22] | 
| Cost |  | $ 1,025,000 | [29],[30] | $ 1,025,000 | [20],[22] | 
| Fair Value |  | 253,000 | [29],[30] | 551,000 | [20],[22] | 
| Investment, Identifier [Axis]: GFRC 360, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 1,000,000 | [24],[25],[27] | 1,000,000 | [17],[19],[28] | 
| Cost |  | 1,000,000 | [27] | 1,000,000 | [28] | 
| Fair Value |  | $ 945,000 | [27] | $ 973,000 | [28] | 
| Investment, Identifier [Axis]: GSM MidCo LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 767,000 | [24],[25],[29],[30] | 767 | [17],[19],[20],[22] | 
| Cost |  | $ 767,000 | [29],[30] | $ 767,000 | [20],[22] | 
| Fair Value |  | 1,562,000 | [29],[30] | 1,359,000 | [20],[22] | 
| Investment, Identifier [Axis]: Giving Home Health Care, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 28,800,000 | [24],[25],[27],[38] | 28,800,000 | [17],[19],[28],[40] | 
| Cost |  | 28,800,000 | [27],[38] | 28,800,000 | [28],[40] | 
| Fair Value |  | $ 28,800,000 | [27],[38] | $ 28,800,000 | [28],[40] | 
| Investment, Identifier [Axis]: Giving Home Health Care, LLC – Warrant |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 10,667,000 | [24],[25],[29],[30] | 10,667 | [17],[19],[20],[22] | 
| Cost |  | $ 19,000 | [29],[30] | $ 19,000 | [20],[22] | 
| Fair Value |  | 2,794,000 | [29],[30] | 19,000 | [20],[22] | 
| Investment, Identifier [Axis]: Gray Matter Systems, LLC – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[40] |  |  | 2,500,000 |  | 
| Cost | [28],[40] |  |  | 2,476,000 |  | 
| Fair Value | [28],[40] |  |  | 2,481,000 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28],[40] |  |  | 4,000,000 |  | 
| Investment, Identifier [Axis]: Gray Matter Systems, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 13,645,000 | [24],[25],[27],[38] | 2,100,000 | [17],[19],[28],[40] | 
| Cost |  | 13,578,000 | [27],[38] | 2,069,000 | [28],[40] | 
| Fair Value |  | 13,645,000 | [27],[38] | 2,084,000 | [28],[40] | 
| Investment, Identifier [Axis]: HH-Inspire Acquisition, Inc. – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[35] |  |  | 10,000,000 |  | 
| Cost | [28],[35] |  |  | 10,000,000 |  | 
| Fair Value | [28],[35] |  |  | 9,925,000 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28],[35] |  |  | 0 |  | 
| Investment, Identifier [Axis]: HH-Inspire Acquisition, Inc. – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 1,359,000 | [24],[25],[27],[34] | 1,500,000 | [17],[19],[28],[35] | 
| Cost |  | 1,359,000 | [27],[34] | 1,500,000 | [28],[35] | 
| Fair Value |  | 1,347,000 | [27],[34] | 1,489,000 | [28],[35] | 
| Line of credit facility, available |  | $ 478,000 | [3],[4],[5],[6],[27],[34] | $ 1,500,000 | [7],[8],[9],[10],[28],[35] | 
| Investment, Identifier [Axis]: HH-Inspire Acquisition, Inc. – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 1,329,054,000 | [24],[25],[29],[30] | 854,848 | [17],[19],[20],[22] | 
| Cost |  | $ 2,251,000 | [29],[30] | $ 956,000 | [20],[22] | 
| Fair Value |  | 3,451,000 | [29],[30] | 945,000 | [20],[22] | 
| Investment, Identifier [Axis]: HH-Inspire Acquisition, Inc. – Term Debt 1 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 16,013,000 | [24],[25],[27],[34] | 16,000,000 | [17],[19],[28],[35] | 
| Cost |  | 16,013,000 | [27],[34] | 16,000,000 | [28],[35] | 
| Fair Value |  | 15,872,000 | [27],[34] | 15,880,000 | [28],[35] | 
| Investment, Identifier [Axis]: HH-Inspire Acquisition, Inc. – Term Debt 2 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 3,225,000 | [24],[25],[27],[34] | 8,000,000 | [17],[19],[28],[35] | 
| Cost |  | 3,225,000 | [27],[34] | 8,000,000 | [28],[35] | 
| Fair Value |  | $ 3,197,000 | [27],[34] | $ 7,940,000 | [28],[35] | 
| Investment, Identifier [Axis]: Imperative Holdings Corporation – Preferred Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 972,569,000 | [24],[25],[29],[30] | 1,474,225 | [17],[19],[20],[22] | 
| Cost |  | $ 488,000 | [29],[30] | $ 632,000 | [20],[22] | 
| Fair Value |  | 2,318,000 | [29],[30] | 2,028,000 | [20],[22] | 
| Investment, Identifier [Axis]: Imperative Holdings Corporation – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 21,015,000 |  |  |  | 
| Cost | [27] | 20,871,000 |  |  |  | 
| Fair Value | [27] | 20,858,000 |  |  |  | 
| Investment, Identifier [Axis]: Imperative Holdings Corporation – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 24,016,000 |  | 
| Cost | [28] |  |  | 23,968,000 |  | 
| Fair Value | [28] |  |  | 23,295,000 |  | 
| Investment, Identifier [Axis]: LWO Acquisitions Company LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[22],[43] |  |  | 95,000 |  | 
| Cost | [22],[43] |  |  | 95,000 |  | 
| Fair Value | [22],[43] |  |  | 0 |  | 
| Investment, Identifier [Axis]: LWO Acquisitions Company LLC—Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 |  |  |  | 
| Fair Value |  | 0 |  | 0 |  | 
| Investment, Identifier [Axis]: Leadpoint Business Services, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 13,500,000 |  |  |  | 
| Cost | [27] | 13,500,000 |  |  |  | 
| Fair Value | [27] | $ 13,399,000 |  |  |  | 
| Investment, Identifier [Axis]: Leeds Novamark Capital I, L.P. – Limited Partnership Interest |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Units | [24],[25],[30],[44],[45] | 3.50% |  |  |  | 
| Cost | [30],[44],[45] | $ 0 |  |  |  | 
| Fair Value | [30],[44],[45] | 231,000 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[30],[44],[45] | 843,000 |  |  |  | 
| Investment, Identifier [Axis]: Lonestar EMS, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[29],[38] | 3,927,000 |  |  |  | 
| Cost | [29],[38] | 3,927,000 |  |  |  | 
| Fair Value | [29],[38] | $ 3,927,000 |  |  |  | 
| Investment, Identifier [Axis]: Lonestar EMS, LLC - Common Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Units |  | 100.00% |  |  |  | 
| Fair Value |  | $ 0 |  | $ 0 |  | 
| Investment, Identifier [Axis]: Lonestar EMS, LLC – Common Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Units |  | 100.00% | [24],[25],[29],[30] | 100.00% | [17],[19],[20],[22] | 
| Cost |  | $ 6,750,000 | [29],[30] | $ 6,750,000 | [20],[22] | 
| Fair Value |  | 0 | [29],[30] | 0 | [20],[22] | 
| Investment, Identifier [Axis]: Lonestar EMS, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[22],[40] |  |  | 3,250,000 |  | 
| Cost | [22],[40] |  |  | 3,250,000 |  | 
| Fair Value | [22],[40] |  |  | 3,030,000 |  | 
| Investment, Identifier [Axis]: Lonestar EMS, LLC—Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 3,927,000 |  |  |  | 
| Fair Value |  | $ 3,927,000 |  | 3,030,000 |  | 
| Investment, Identifier [Axis]: MCG Energy Solutions, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 0 |  | 
| Cost | [28] |  |  | 0 |  | 
| Fair Value | [28] |  |  | 0 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28] |  |  | $ 3,000,000 |  | 
| Investment, Identifier [Axis]: MCG Energy Solutions, LLC – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 7,000,000,000 | [24],[25],[29],[30] | 7,000,000 | [17],[19],[22] | 
| Cost |  | $ 7,000,000 | [29],[30] | $ 7,000,000 | [22] | 
| Fair Value |  | 8,904,000 | [29],[30] | 8,151,000 | [22] | 
| Investment, Identifier [Axis]: MCG Energy Solutions, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 20,146,000 |  |  |  | 
| Cost | [27] | 20,107,000 |  |  |  | 
| Fair Value | [27] | $ 17,628,000 |  |  |  | 
| Investment, Identifier [Axis]: MCG Energy Solutions, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 20,820,000 |  | 
| Cost | [28] |  |  | 20,820,000 |  | 
| Fair Value | [28] |  |  | $ 19,779,000 |  | 
| Investment, Identifier [Axis]: NeoGraf Solutions LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [24],[25],[29],[30] | 2,000,000,000 |  |  |  | 
| Cost | [29],[30] | $ 2,000,000 |  |  |  | 
| Fair Value | [29],[30] | 0 |  |  |  | 
| Investment, Identifier [Axis]: NeoGraf Solutions LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 0 |  |  |  | 
| Cost | [27] | 0 |  |  |  | 
| Fair Value | [27] | 0 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[27] | 4,500,000 |  |  |  | 
| Investment, Identifier [Axis]: NeoGraf Solutions LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 27,154,000 |  |  |  | 
| Cost | [27] | 27,154,000 |  |  |  | 
| Fair Value | [27] | $ 26,000,000 |  |  |  | 
| Investment, Identifier [Axis]: NetFortris Corp. – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [17],[19],[20],[22] |  |  | 7,890,860 |  | 
| Cost | [20],[22] |  |  | $ 789,000 |  | 
| Fair Value | [20],[22] |  |  | 469,000 |  | 
| Investment, Identifier [Axis]: OCI, LLC – Common Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [24],[25],[29],[30] | 306,000 |  |  |  | 
| Cost | [29],[30] | $ 0 |  |  |  | 
| Fair Value | [29],[30] | 0 |  |  |  | 
| Investment, Identifier [Axis]: OCI, LLC – Term Debt 1 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 20,000,000 |  |  |  | 
| Cost | [27] | 20,000,000 |  |  |  | 
| Fair Value | [27] | 19,800,000 |  |  |  | 
| Investment, Identifier [Axis]: OCI, LLC – Term Debt 2 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[38] | 2,012,000 |  |  |  | 
| Cost | [27],[38] | 2,012,000 |  |  |  | 
| Fair Value | [27],[38] | $ 1,992,000 |  |  |  | 
| Investment, Identifier [Axis]: Ohio Armor Holdings, LLC – Common Equity |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [24],[25],[29],[30] | 100,000 |  |  |  | 
| Cost | [29],[30] | $ 1,000,000 |  |  |  | 
| Fair Value | [29],[30] | 680,000 |  |  |  | 
| Investment, Identifier [Axis]: Ohio Armor Holdings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 17,738,000 | [24],[25],[27] | 18,913,000 | [17],[19],[28] | 
| Cost |  | 17,738,000 | [27] | 18,913,000 | [28] | 
| Fair Value |  | $ 17,294,000 | [27] | $ 18,558,000 | [28] | 
| Investment, Identifier [Axis]: PIC 360, LLC – Common Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 750,000 | [24],[25],[29],[30] | 750 | [17],[19],[20],[22] | 
| Cost |  | $ 1,000 | [29],[30] | $ 1,000 | [20],[22] | 
| Fair Value |  | $ 284,000 | [29],[30] | 3,454,000 | [20],[22] | 
| Investment, Identifier [Axis]: PIC 360, LLC—Common Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 750 |  |  |  | 
| Fair Value |  | $ 284,000 |  | 3,454,000 |  | 
| Investment, Identifier [Axis]: Pansophic Learning, Ltd. – Term Debt 1 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 28,000,000 | [24],[25],[27],[34] | 28,000,000 | [17],[19],[28] | 
| Cost |  | 27,968,000 | [27],[34] | 27,961,000 | [28] | 
| Fair Value |  | 27,965,000 | [27],[34] | 27,825,000 | [28] | 
| Investment, Identifier [Axis]: Pansophic Learning, Ltd. – Term Debt 2 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 5,000,000 | [24],[25],[27],[34] | 5,000,000 | [17],[19],[28] | 
| Cost |  | 4,994,000 | [27],[34] | 4,993,000 | [28] | 
| Fair Value |  | $ 4,994,000 | [27],[34] | 4,969,000 | [28] | 
| Investment, Identifier [Axis]: R2i Holdings, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[40],[46] |  |  | 829,000 |  | 
| Cost | [40],[46] |  |  | 829,000 |  | 
| Fair Value | [40],[46] |  |  | 829,000 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[40],[46] |  |  | 1,171,000 |  | 
| Investment, Identifier [Axis]: R2i Holdings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[40],[46] |  |  | 18,000,000 |  | 
| Cost | [40],[46] |  |  | 18,000,000 |  | 
| Fair Value | [40],[46] |  |  | 18,000,000 |  | 
| Investment, Identifier [Axis]: Salt & Straw, LLC – Common Warrant |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Units | [24],[25],[29],[30] | 0.40% |  |  |  | 
| Cost | [29],[30] | $ 0 |  |  |  | 
| Fair Value | [29],[30] | 31,000 |  |  |  | 
| Investment, Identifier [Axis]: Salt & Straw, LLC – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 10,200,000 | [24],[25],[27] | 0 | [17],[19],[28] | 
| Cost |  | 10,133,000 | [27] | 0 | [28] | 
| Fair Value |  | 9,715,000 | [27] | 0 | [28] | 
| Line of credit facility, available |  | 1,300,000 | [3],[4],[5],[6],[27] | 11,500,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Salt & Straw, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 | [24],[25],[27] | 800,000 | [17],[19],[28] | 
| Cost |  | 0 | [27] | 800,000 | [28] | 
| Fair Value |  | 0 | [27] | 800,000 | [28] | 
| Line of credit facility, available |  | $ 2,000,000 | [3],[4],[5],[6],[27] | $ 1,200,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Salvo Technologies, Inc. – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 2,500,000 | [24],[25],[29],[30] | 2,500 | [17],[19],[20],[22] | 
| Cost |  | $ 2,500,000 | [29],[30] | $ 2,500,000 | [20],[22] | 
| Fair Value |  | 1,225,000 | [29],[30] | 2,584,000 | [20],[22] | 
| Investment, Identifier [Axis]: Salvo Technologies, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 11,768,000 | [24],[25],[27] | 11,887,000 | [17],[19],[28],[31] | 
| Cost |  | 11,768,000 | [27] | 11,887,000 | [28],[31] | 
| Fair Value |  | $ 10,900,000 | [27] | $ 11,619,000 | [28],[31] | 
| Investment, Identifier [Axis]: Sea Link International IRB, Inc. – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 98,039,000 | [24],[25],[29],[30] | 98,039 | [17],[19],[20],[22] | 
| Cost |  | $ 98,000 | [29],[30] | $ 98,000 | [20],[22] | 
| Fair Value |  | 183,000 | [29],[30] | 153,000 | [20],[22] | 
| Investment, Identifier [Axis]: Sea Link International IRB, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[40] |  |  | 11,719,000 |  | 
| Cost | [28],[40] |  |  | 11,679,000 |  | 
| Fair Value | [28],[40] |  |  | $ 11,074,000 |  | 
| Investment, Identifier [Axis]: Sea Link International IRB, Inc. – Term Debt 1 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[38] | 12,083,000 |  |  |  | 
| Cost | [27],[38] | 12,053,000 |  |  |  | 
| Fair Value | [27],[38] | 11,675,000 |  |  |  | 
| Investment, Identifier [Axis]: Sea Link International IRB, Inc. – Term Debt 2 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[38] | 4,000,000 |  |  |  | 
| Cost | [27],[38] | 4,000,000 |  |  |  | 
| Fair Value | [27],[38] | $ 4,000,000 |  |  |  | 
| Investment, Identifier [Axis]: Sea Link International IRB, Inc.– Common Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 823,333,000 | [24],[25],[29],[30] | 823,333 | [17],[19],[20],[22] | 
| Cost |  | $ 823,000 | [29],[30] | $ 823,000 | [20],[22] | 
| Fair Value |  | $ 340,000 | [29],[30] | $ 105,000 | [20],[22] | 
| Investment, Identifier [Axis]: Sokol & Company Holdings, LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 1,500,000,000 | [24],[25],[29],[30] | 1,500,000 | [17],[19],[20],[22] | 
| Cost |  | $ 1,500,000 | [29],[30] | $ 1,500,000 | [20],[22] | 
| Fair Value |  | 1,612,000 | [29],[30] | 1,500,000 | [20],[22] | 
| Investment, Identifier [Axis]: Sokol & Company Holdings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[31] |  |  | 13,500,000 |  | 
| Cost | [28],[31] |  |  | 13,500,000 |  | 
| Fair Value | [28],[31] |  |  | 13,500,000 |  | 
| Investment, Identifier [Axis]: Sokol & Company Holdings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 13,500,000 |  |  |  | 
| Cost | [27] | 13,500,000 |  |  |  | 
| Fair Value | [27] | 13,095,000 |  |  |  | 
| Investment, Identifier [Axis]: SpaceCo Holdings, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 1,450,000 | [24],[25],[27],[34] | 1,900,000 | [17],[19],[28],[35] | 
| Cost |  | 1,450,000 | [27],[34] | 1,900,000 | [28],[35] | 
| Fair Value |  | 1,434,000 | [27],[34] | 1,886,000 | [28],[35] | 
| Line of credit facility, available |  | 550,000 | [3],[4],[5],[6],[27],[34] | 100,000 | [7],[8],[9],[10],[28],[35] | 
| Investment, Identifier [Axis]: SpaceCo Holdings, LLC – Term Deb |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[35] |  |  | 31,719,000 |  | 
| Cost | [28],[35] |  |  | 31,326,000 |  | 
| Fair Value | [28],[35] |  |  | 31,481,000 |  | 
| Investment, Identifier [Axis]: SpaceCo Holdings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[34] | 30,284,000 |  |  |  | 
| Cost | [27],[34] | 29,961,000 |  |  |  | 
| Fair Value | [27],[34] | 29,944,000 |  |  |  | 
| Investment, Identifier [Axis]: Springfield, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 30,000,000 | [24],[25],[27] | 30,000,000 | [17],[19],[28] | 
| Cost |  | 30,000,000 | [27] | 30,000,000 | [28] | 
| Fair Value |  | $ 29,850,000 | [27] | $ 29,738,000 | [28] | 
| Investment, Identifier [Axis]: TNCP Intermediate HoldCo, LLC – Common Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 790,000,000 | [24],[25],[29],[30] | 790,000 | [17],[19],[20],[22] | 
| Cost |  | $ 500,000 | [29],[30] | $ 500,000 | [20],[22] | 
| Fair Value |  | 3,073,000 | [29],[30] | 2,337,000 | [20],[22] | 
| Investment, Identifier [Axis]: TNCP Intermediate HoldCo, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 900,000 | [24],[25],[29],[38] | 1,000,000 | [17],[19],[22],[40] | 
| Cost |  | 900,000 | [29],[38] | 1,000,000 | [22],[40] | 
| Fair Value |  | 900,000 | [29],[38] | 1,000,000 | [22],[40] | 
| Line of credit facility, available | [7],[8],[9],[10],[22],[40] |  |  | 1,000,000 |  | 
| Investment, Identifier [Axis]: TNCP Intermediate HoldCo, LLC—-Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 900,000 |  |  |  | 
| Fair Value |  | 900,000 |  | 1,000,000 |  | 
| Line of credit facility, available | [3],[4],[5],[6],[29],[38] | $ 1,100,000 |  |  |  | 
| Investment, Identifier [Axis]: TNCP Intermediate HoldCo, LLC—Common Equity Units |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 790,000 |  |  |  | 
| Fair Value |  | $ 3,073,000 |  | 2,337,000 |  | 
| Investment, Identifier [Axis]: Tailwind Smith Cooper Intermediate Corporation – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 5,000,000 | [23],[24],[25],[34] | 5,000,000 | [17],[19],[26] | 
| Cost |  | 4,856,000 | [23],[34] | 4,829,000 | [26] | 
| Fair Value |  | $ 4,294,000 | [23],[34] | $ 4,313,000 | [26] | 
| Investment, Identifier [Axis]: Targus Cayman HoldCo, Ltd. – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [17],[19],[20],[46],[47] |  |  | 3,076,414 |  | 
| Cost | [20],[46],[47] |  |  | $ 2,062,000 |  | 
| Fair Value | [20],[46],[47] |  |  | $ 7,978,000 |  | 
| Investment, Identifier [Axis]: Technical Resource Management, LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [24],[25],[29],[30] | 2,000,000,000 |  |  |  | 
| Cost | [29],[30] | $ 2,000,000 |  |  |  | 
| Fair Value | [29],[30] | 1,415,000 |  |  |  | 
| Investment, Identifier [Axis]: Technical Resource Management, LLC – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 0 |  |  |  | 
| Cost | [27] | 0 |  |  |  | 
| Fair Value | [27] | 0 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[27] | 2,500,000 |  |  |  | 
| Investment, Identifier [Axis]: Technical Resource Management, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 2,000,000 |  |  |  | 
| Cost | [27] | 2,000,000 |  |  |  | 
| Fair Value | [27] | 1,970,000 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[27] | 1,000,000 |  |  |  | 
| Investment, Identifier [Axis]: Technical Resource Management, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 23,000,000 |  |  |  | 
| Cost | [27] | 23,000,000 |  |  |  | 
| Fair Value | [27] | $ 22,655,000 |  |  |  | 
| Investment, Identifier [Axis]: Total Safety Holdings, LLC – Common Equity |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 435,000 | [24],[25],[29],[30] | 435 | [17],[19],[20],[22] | 
| Cost |  | $ 499,000 | [29],[30] | $ 499,000 | [20],[22] | 
| Fair Value |  | $ 146,000 | [29],[30] | $ 50,000 | [20],[22] | 
| Investment, Identifier [Axis]: Triple H Food Processors, LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 250,000,000 | [24],[25],[29],[30] | 250,000 | [17],[19],[20],[22] | 
| Cost |  | $ 250,000 | [29],[30] | $ 250,000 | [20],[22] | 
| Fair Value |  | $ 1,641,000 | [29],[30] | $ 672,000 | [20],[22] | 
| Investment, Identifier [Axis]: Triple H Food Processors, LLC – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 75,000 | [24],[25],[29],[30] | 75 | [17],[19],[20],[22] | 
| Cost |  | $ 75,000 | [29],[30] | $ 75,000 | [20],[22] | 
| Fair Value |  | 141,000 | [29],[30] | 120,000 | [20],[22] | 
| Investment, Identifier [Axis]: Trowbridge Chicago, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 0 |  |  |  | 
| Cost | [27] | 0 |  |  |  | 
| Fair Value | [27] | 0 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[27] | $ 2,000,000 |  |  |  | 
| Investment, Identifier [Axis]: Trowbridge Chicago, LLC – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [24],[25],[29],[30] | 242,105,000 |  |  |  | 
| Cost | [29],[30] | $ 750,000 |  |  |  | 
| Fair Value | [29],[30] | 750,000 |  |  |  | 
| Investment, Identifier [Axis]: Trowbridge Chicago, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 5,750,000 |  |  |  | 
| Cost | [27] | 5,750,000 |  |  |  | 
| Fair Value | [27] | 5,664,000 |  |  |  | 
| Investment, Identifier [Axis]: Turn Key Health Clinics, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 500,000 | [24],[25],[27] | 500,000 | [17],[19],[28] | 
| Cost |  | 500,000 | [27] | 500,000 | [28] | 
| Fair Value |  | 499,000 | [27] | 495,000 | [28] | 
| Line of credit facility, available |  | 1,500,000 | [3],[4],[5],[6],[27] | 1,500,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Turn Key Health Clinics, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 11,000,000 | [24],[25],[27] | 11,000,000 | [17],[19],[28] | 
| Cost |  | 11,000,000 | [27] | 11,000,000 | [28] | 
| Fair Value |  | 10,986,000 | [27] | 10,890,000 | [28] | 
| Investment, Identifier [Axis]: Unirac Holdings, Inc. – Delayed Draw Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 1,108,000 | [24],[25],[27] | 0 | [17],[19],[28],[31] | 
| Cost |  | 1,108,000 | [27] | 0 | [28],[31] | 
| Fair Value |  | 1,111,000 | [27] | 0 | [28],[31] | 
| Line of credit facility, available |  | 1,669,000 | [3],[4],[5],[6],[27] | 2,778,000 | [7],[8],[9],[10],[28],[31] | 
| Investment, Identifier [Axis]: Unirac Holdings, Inc. – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 978,000 | [24],[25],[27] | 0 | [17],[19],[28],[31] | 
| Cost |  | 978,000 | [27] | 0 | [28],[31] | 
| Fair Value |  | 980,000 | [27] | 0 | [28],[31] | 
| Line of credit facility, available |  | 1,244,000 | [3],[4],[5],[6],[27] | 2,222,000 | [7],[8],[9],[10],[28],[31] | 
| Investment, Identifier [Axis]: Unirac Holdings, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 14,888,000 |  |  |  | 
| Cost | [27] | 14,577,000 |  |  |  | 
| Fair Value | [27] | 14,925,000 |  |  |  | 
| Investment, Identifier [Axis]: Unirac Holdings, Inc. – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[31] |  |  | 15,000,000 |  | 
| Cost | [28],[31] |  |  | 14,628,000 |  | 
| Fair Value | [28],[31] |  |  | 15,000,000 |  | 
| Investment, Identifier [Axis]: Viva Railings, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 0 | [24],[25],[27] | 0 | [17],[19],[28] | 
| Cost |  | 0 | [27] | 0 | [28] | 
| Fair Value |  | 0 | [27] | 0 | [28] | 
| Line of credit facility, available |  | 4,000,000 | [3],[4],[5],[6],[27] | 4,000,000 | [7],[8],[9],[10],[28] | 
| Investment, Identifier [Axis]: Viva Railings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 20,747,000 |  |  |  | 
| Cost | [27] | 20,747,000 |  |  |  | 
| Fair Value | [27] | $ 20,436,000 |  |  |  | 
| Investment, Identifier [Axis]: Viva Railings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28] |  |  | 21,800,000 |  | 
| Cost | [28] |  |  | 21,800,000 |  | 
| Fair Value | [28] |  |  | $ 21,364,000 |  | 
| Investment, Identifier [Axis]: WB Xcel Holdings, LLC - Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [17],[19],[20],[22] |  |  | 333 |  | 
| Cost | [20],[22] |  |  | $ 2,750,000 |  | 
| Fair Value | [20],[22] |  |  | 5,687,000 |  | 
| Investment, Identifier [Axis]: WB Xcel Holdings, LLC - Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 333 |  |  |  | 
| Fair Value |  | $ 0 |  | 5,687,000 |  | 
| Investment, Identifier [Axis]: WB Xcel Holdings, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 1,468,000 | [24],[25],[29] | 1,468,000 | [17],[19],[22] | 
| Cost |  | 1,468,000 | [29] | 1,468,000 | [22] | 
| Fair Value |  | 1,468,000 | [29] | 1,468,000 | [22] | 
| Line of credit facility, available |  | $ 32,000 | [3],[4],[5],[6],[29] | 32,000 | [7],[8],[9],[10],[22] | 
| Investment, Identifier [Axis]: WB Xcel Holdings, LLC – Preferred Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares | [24],[25],[29],[30] | 333,000 |  |  |  | 
| Cost | [29],[30] | $ 2,750,000 |  |  |  | 
| Fair Value | [29],[30] | 0 |  |  |  | 
| Investment, Identifier [Axis]: WB Xcel Holdings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[29] | 9,825,000 |  |  |  | 
| Cost | [29] | 9,825,000 |  |  |  | 
| Fair Value | [29] | 9,825,000 |  |  |  | 
| Investment, Identifier [Axis]: WB Xcel Holdings, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[22] |  |  | 9,925,000 |  | 
| Cost | [22] |  |  | 9,925,000 |  | 
| Fair Value | [22] |  |  | 9,925,000 |  | 
| Investment, Identifier [Axis]: WB Xcel Holdings, LLC—Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 1,468,000 |  |  |  | 
| Fair Value |  | 1,468,000 |  | 1,468,000 |  | 
| Investment, Identifier [Axis]: WB Xcel Holdings, LLC—Term Loan |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount |  | 9,825,000 |  |  |  | 
| Fair Value |  | $ 9,825,000 |  | $ 9,925,000 |  | 
| Investment, Identifier [Axis]: WorkforceQA, LLC – Common Stock |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Shares |  | 532,000 | [24],[25],[29],[30] | 500 | [17],[19],[20],[22] | 
| Cost |  | $ 532,000 | [29],[30] | $ 500,000 | [20],[22] | 
| Fair Value |  | 359,000 | [29],[30] | 456,000 | [20],[22] | 
| Investment, Identifier [Axis]: WorkforceQA, LLC – Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27] | 400,000 |  |  |  | 
| Cost | [27] | 400,000 |  |  |  | 
| Fair Value | [27] | 400,000 |  |  |  | 
| Line of credit facility, available | [3],[4],[5],[6],[27] | 1,600,000 |  |  |  | 
| Investment, Identifier [Axis]: WorkforceQA, LLC – Term Debt |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[35],[48] |  |  | 10,000,000 |  | 
| Cost | [28],[35],[48] |  |  | 10,000,000 |  | 
| Fair Value | [28],[35],[48] |  |  | 9,975,000 |  | 
| Investment, Identifier [Axis]: WorkforceQA, LLC – Term Debt 1 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[49] | 10,000,000 |  |  |  | 
| Cost | [27],[49] | 9,971,000 |  |  |  | 
| Fair Value | [27],[49] | 9,987,000 |  |  |  | 
| Investment, Identifier [Axis]: WorkforceQA, LLC – Term Debt 2 |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [24],[25],[27],[49] | 1,600,000 |  |  |  | 
| Cost | [27],[49] | 1,595,000 |  |  |  | 
| Fair Value | [27],[49] | $ 1,598,000 |  |  |  | 
| Investment, Identifier [Axis]: WorkforceQA, LLC– Line of Credit |  |  |  |  |  | 
| Schedule of Investments [Line Items] |  |  |  |  |  | 
| Principal amount | [17],[19],[28],[35] |  |  | 0 |  | 
| Cost | [28],[35] |  |  | 0 |  | 
| Fair Value | [28],[35] |  |  | 0 |  | 
| Line of credit facility, available | [7],[8],[9],[10],[28],[35] |  |  | $ 2,000,000 |  | 
|  | 
|  |