Change in Year End - Schedule of Financial Data (Details) - USD ($)	3 Months Ended												9 Months Ended		12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Mar. 31, 2022
Investment Income
Interest income (excluding Payment-in-kind ("PIK") interest income)													$ 203,332,000	$ 169,457,000
PIK interest income													2,222,000	2,662,000	$ 3,006,000	$ 4,075,000
Dividend income													1,397,000	779,000
Other income													1,793,000	2,711,000
Total Investment Income	$ 71,952,000	$ 68,175,000	$ 68,617,000	$ 67,778,000	$ 63,320,000	$ 58,885,000	$ 53,404,000	$ 54,741,000	$ 54,972,000	$ 52,889,000	$ 50,553,000	$ 50,825,000	208,744,000	175,609,000	276,522,000	213,155,000
Operating Expenses
Management fees													13,105,000	26,621,000	17,369,000	36,142,000
Performance-based incentive fees													18,369,000	5,691,000	24,565,000	11,681,000
Interest and other debt expenses													79,432,000	59,363,000	104,198,000	55,020,000
Administrative services expense													4,418,000	4,188,000	5,840,000	5,835,000
Other general and administrative expenses													7,875,000	6,551,000	10,131,000	9,106,000
Total expenses													123,199,000	102,414,000	162,103,000	117,784,000
Performance-based incentive fee offset														(178,000)	(274,000)	(247,000)
Expense reimbursements													(971,000)	(770,000)
Net Expenses													122,228,000	101,466,000	160,523,000	117,194,000
Net Investment Income	29,769,000	27,896,000	28,850,000	29,484,000	28,013,000	22,637,000	23,493,000	26,889,000	22,496,000	21,231,000	25,345,000	25,635,000	86,516,000	74,143,000	115,999,000	95,961,000
Net Realized and Change in Unrealized Gains (Losses)
Net realized gains (losses)													1,034,000	(69,239,000)	200,000	(67,367,000)
Net change in unrealized gains (losses)													1,078,000	18,036,000	2,561,000	53,770,000
Net Realized and Change in Unrealized Gains (Losses)	3,492,000	2,067,000	(3,447,000)	649,000	(26,725,000)	(6,644,000)	(17,834,000)	(22,650,000)	(1,956,000)	4,210,000	6,799,000	16,777,000	2,112,000	(51,203,000)	2,761,000	(13,597,000)
Net Increase (Decrease) in Net Assets Resulting from Operations	$ 33,262,000	$ 29,963,000	$ 25,404,000	$ 30,132,000	$ 1,288,000	$ 15,993,000	$ 5,659,000	$ 4,239,000	$ 20,540,000	$ 25,441,000	$ 32,144,000	$ 42,411,000	$ 88,628,000	$ 22,940,000	$ 118,760,000	$ 82,364,000
Basic earnings (loss) per share													$ 1.36	$ 0.36	$ 1.82	$ 1.28