INCOME TAXES - Net Assets Resulting from Operations to Estimated RIC Taxable Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Net increase in net assets from operations	$ 17,561	$ 16,268	$ 22,684	$ 14,035	$ 13,469	$ 23,484	$ 22,624	$ 23,812	$ 70,548	$ 83,389	$ 33,093
Net unrealized (appreciation) depreciation on investments									(2,423)	(13,640)	18,589
(Expense/loss) income/gain recognized for tax on pass-through entities									(80)	(6,383)	962
Realized loss (gain) book/tax differences									(10,876)	18,962	(389)
Capital loss carryover									70,883	26,449	12,796
Net operating income - wholly-owned subsidiary									(14,568)	(5,194)	809
Dividend income from wholly-owned subsidiary									9,038	2,000	1,068
Non-deductible tax expense									1,424	921	628
Loss on extinguishment of debt									(2,726)	(2,726)	(2,726)
Non-deductible compensation									6,693	3,665	3,243
Compensation related book/tax differences									(2,741)	1,116	812
Interest on non-accrual loans									11,999	5,636	3,343
Other book/tax differences									(187)	1,515	107
Estimated distributable income before deductions for distributions									136,984	115,710	72,335
Ordinary									123,569	101,517	70,034
Estimated annual RIC undistributed taxable income									13,415	$ 14,193	$ 2,301
Capital loss carryforwards	$ 131,000								$ 131,000