FAIR VALUE MEASUREMENTS - Changes in Fair Value of Investments Measured Using Level 3 Inputs (Details) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
First lien loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	$ 1,309,449	$ 1,000,984
Realized & Unrealized Gains (Losses)	(39,763)	(9,874)
Purchases of Investments	466,533	307,934
Repayments	(197,759)	(139,778)
PIK Interest Capitalized	8,720	7,925
Divestitures	(27,308)	(13,875)
Conversion/Exchange of Security	(4,730)	(6,961)
Fair value. ending balance	1,515,142	1,146,355
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	(28,533)	(4,920)
Second lien loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	33,774	35,820
Realized & Unrealized Gains (Losses)	(3,011)	989
Purchases of Investments	18	187
Repayments	(3,629)	(2,596)
PIK Interest Capitalized	70	214
Divestitures	0	0
Conversion/Exchange of Security	(1,062)	0
Fair value. ending balance	26,160	34,614
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	(1,130)	987
Subordinated debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	1,336	791
Realized & Unrealized Gains (Losses)	43	(28)
Purchases of Investments	57	0
Repayments	(75)	(20)
PIK Interest Capitalized	14	25
Divestitures	0	0
Conversion/Exchange of Security	(153)	0
Fair value. ending balance	1,222	768
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	34	(28)
Preferred equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	71,127	63,393
Realized & Unrealized Gains (Losses)	7,359	(5,532)
Purchases of Investments	6,730	7,886
Repayments	0	0
PIK Interest Capitalized	0	0
Divestitures	0	(273)
Conversion/Exchange of Security	0	3,170
Fair value. ending balance	85,216	68,644
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	7,359	(5,430)
Common equity & warrants
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	60,875	54,144
Realized & Unrealized Gains (Losses)	2,031	622
Purchases of Investments	4,695	5,757
Repayments	0	0
PIK Interest Capitalized	0	0
Divestitures	0	(3,858)
Conversion/Exchange of Security	5,945	3,791
Fair value. ending balance	73,546	60,456
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	2,830	390
Total Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	1,476,561	1,155,132
Realized & Unrealized Gains (Losses)	(33,341)	(13,823)
Purchases of Investments	478,033	321,764
Repayments	(201,463)	(142,394)
PIK Interest Capitalized	8,804	8,164
Divestitures	(27,308)	(18,006)
Conversion/Exchange of Security	0	0
Fair value. ending balance	1,701,286	1,310,837
YTD Unrealized Appreciation (Depreciation) on Investments held at period end	(19,440)	$ (9,001)
Cost basis allocated from first lien debt to warrants
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Conversion/Exchange of Security	$ 3,800