CONSOLIDATED STATEMENTS OF CHANGES IN NET ASSETS - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Investment Company, Net Assets [Roll Forward]
Beginning balance (in shares)		45,050,759			45,050,759
Beginning balance	$ 777,331	$ 755,676	$ 636,201	$ 590,408	$ 755,676	$ 590,408
Issuance of common stock	20,237	37,778	22,493	44,872
Cancellation of treasury shares				0
Share-based compensation	1,538	1,224	1,236	963
Issuance of common stock under restricted stock plan, net of forfeitures	0	0	0	0
Common stock withheld for payroll taxes upon vesting of restricted stock		(1,862)		(926)
Dividends to shareholders	(30,520)	(29,508)	(24,769)	(22,916)
Change in restoration plan liability	(12)	(12)	(11)	(12)
Net investment income	31,165	28,859	27,194	24,556	60,024	51,750
Net realized gain on investments and extinguishment of debt			29
Net realized (loss) gain on investments	(10,289)	711	390	(12,782)	(9,578)	(12,392)
Net realized loss on investments and extinguishment of debt	(10,289)
Net unrealized appreciation (depreciation) on investments	$ 1,808	(15,535)	$ (4,599)	12,038	$ (13,727)	$ 7,439
Ending balance (in shares)	47,686,685		39,951,000		47,686,685	39,951,000
Ending balance	$ 791,258	$ 777,331	$ 657,774	$ 636,201	$ 791,258	$ 657,774
Common Stock
Investment Company, Net Assets [Roll Forward]
Beginning balance (in shares)	46,837,511	45,050,759	38,839,918	36,076,425	45,050,759	36,076,425
Beginning balance	$ 11,709	$ 11,263	$ 9,710	$ 9,604	$ 11,263	$ 9,604
Issuance of common stock (in shares)	839,099	1,498,981	1,100,000	2,527,458
Issuance of common stock	$ 210	$ 375	$ 275	$ 632
Cancellation of treasury shares				$ (585)
Issuance of common stock under restricted stock plan, net of forfeitures (in shares)	10,075	359,000	11,200	282,616
Issuance of common stock under restricted stock plan, net of forfeitures	$ 3	$ 89	$ 3	$ 71
Common stock withheld for payroll taxes upon vesting of restricted stock (in shares)		(71,229)		(46,581)
Common stock withheld for payroll taxes upon vesting of restricted stock		$ (18)		$ (12)
Ending balance (in shares)	47,686,685	46,837,511	39,951,118	38,839,918	47,686,685	39,951,118
Ending balance	$ 11,922	$ 11,709	$ 9,988	$ 9,710	$ 11,922	$ 9,988
Treasury Stock
Investment Company, Net Assets [Roll Forward]
Beginning balance	$ 0	$ 0	$ 0	$ (23,937)	$ 0	$ (23,937)
Beginning balance (in shares)	0	0	0	2,339,512	0	2,339,512
Cancellation of treasury shares				$ 23,937
Cancellation of treasury stock (in shares)				(2,339,512)
Ending balance	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Ending balance (in shares)	0	0	0	0	0	0
Additional Paid-In Capital
Investment Company, Net Assets [Roll Forward]
Beginning balance	$ 833,627	$ 796,945	$ 667,440	$ 646,586	$ 796,945	$ 646,586
Issuance of common stock	20,027	37,403	22,218	44,240
Cancellation of treasury shares				(23,352)
Share-based compensation	1,538	1,224	1,236	963
Issuance of common stock under restricted stock plan, net of forfeitures	(3)	(89)	(3)	(71)
Common stock withheld for payroll taxes upon vesting of restricted stock		(1,844)		(914)
Change in restoration plan liability	(12)	(12)	(11)	(12)
Ending balance	855,177	833,627	690,880	667,440	855,177	690,880
Total Distributable Earnings (Loss)
Investment Company, Net Assets [Roll Forward]
Beginning balance	(68,005)	(52,532)	(40,949)	(41,845)	(52,532)	(41,845)
Dividends to shareholders	(30,520)	(29,508)	(24,769)	(22,916)
Net investment income	31,165	28,859	27,194	24,556
Net realized gain on investments and extinguishment of debt			29
Net realized (loss) gain on investments		711		(12,782)
Net realized loss on investments and extinguishment of debt	(10,289)
Net unrealized appreciation (depreciation) on investments	1,808	(15,535)	(4,599)	12,038
Ending balance	$ (75,841)	$ (68,005)	$ (43,094)	$ (40,949)	$ (75,841)	$ (43,094)