FAIR VALUE MEASUREMENTS - Changes in Fair Value of Investments Measured Using Level 3 Inputs (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
First lien loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	$ 1,586,622	$ 1,309,449
Realized & Unrealized Gains (Losses)	(8,848)	(7,503)
Purchases of Investments	95,536	93,666
Repayments	(75,234)	(85,047)
PIK Interest Capitalized	3,002	3,512
Divestitures	(1,789)	(8,171)
Conversion/Exchange of Security	(3,951)	0
Fair value. ending balance	1,595,338	1,305,906
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	(5,913)	(7,945)
Second lien loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	18,066	33,774
Realized & Unrealized Gains (Losses)	(696)	(2,567)
Purchases of Investments	13	26
Repayments	0	(3,210)
PIK Interest Capitalized	0	70
Divestitures	0	0
Conversion/Exchange of Security	0	0
Fair value. ending balance	17,383	28,093
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	(696)	(2,565)
Subordinated debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	1,218	1,336
Realized & Unrealized Gains (Losses)	1	31
Purchases of Investments	57	57
Repayments	(15)	0
PIK Interest Capitalized	3	9
Divestitures	0	0
Conversion/Exchange of Security	0	(153)
Fair value. ending balance	1,264	1,280
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	1	23
Preferred equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	102,918	71,127
Realized & Unrealized Gains (Losses)	(6,959)	(45)
Purchases of Investments	826	1,804
Repayments	0	0
PIK Interest Capitalized	0	0
Divestitures	(29,867)	0
Conversion/Exchange of Security	(688)	0
Fair value. ending balance	66,230	72,886
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	(2,494)	(45)
Common equity & warrants
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	76,475	60,875
Realized & Unrealized Gains (Losses)	14,267	(4,690)
Purchases of Investments	1,145	3,623
Repayments	0	0
PIK Interest Capitalized	0	0
Divestitures	0	0
Conversion/Exchange of Security	4,639	153
Fair value. ending balance	96,526	59,961
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	14,267	(3,891)
Earnout
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	0
Realized & Unrealized Gains (Losses)	0
Purchases of Investments	3,457
Repayments	0
PIK Interest Capitalized	0
Divestitures	0
Conversion/Exchange of Security	0
Fair value. ending balance	3,457
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	0
Total Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	1,785,299	1,476,561
Realized & Unrealized Gains (Losses)	(2,235)	(14,774)
Purchases of Investments	101,034	99,176
Repayments	(75,249)	(88,257)
PIK Interest Capitalized	3,005	3,591
Divestitures	(31,656)	(8,171)
Conversion/Exchange of Security	0	0
Fair value. ending balance	1,780,198	1,468,126
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	$ 5,165	$ (14,423)