CONSOLIDATED STATEMENTS OF CHANGES IN NET ASSETS - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2024	Dec. 31, 2023
Investment Company, Net Assets [Roll Forward]
Beginning balance (in shares)			45,050,759				45,050,759
Beginning balance	$ 791,258	$ 777,331	$ 755,676	$ 657,774	$ 636,201	$ 590,408	$ 755,676	$ 590,408
Issuance of common stock	52,915	20,237	37,778	65,527	22,493	44,872
Cancellation of treasury shares						0
Share-based compensation	1,544	1,538	1,224	1,188	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)	(138)		(926)
Dividends to shareholders	(31,532)	(30,520)	(29,508)	(26,858)	(24,769)	(22,916)
Change in restoration plan liability	(11)	(12)	(12)	(12)	(11)	(12)
Reclassification for certain permanent book-to-tax differences	0			0
Net investment income	30,316	31,165	28,859	28,859	27,194	24,556	90,340	80,609
Net realized (loss) gain on investments	(12,805)		711	(7,842)		(12,782)	(22,383)	(20,234)
Net realized loss on investments and extinguishment of debt	(13,201)	(10,289)			29
Net unrealized appreciation (depreciation) on investments	$ (847)	1,808	(15,535)	$ 2,467	(4,599)	12,038	$ (14,574)	$ 9,906
Ending balance (in shares)	50,051,332			42,981,000			50,051,332	42,981,000
Ending balance	$ 830,442	$ 791,258	$ 777,331	$ 720,965	$ 657,774	$ 636,201	$ 830,442	$ 720,965
Common Stock
Investment Company, Net Assets [Roll Forward]
Beginning balance (in shares)	47,686,685	46,837,511	45,050,759	39,951,118	38,839,918	36,076,425	45,050,759	36,076,425
Beginning balance	$ 11,922	$ 11,709	$ 11,263	$ 9,988	$ 9,710	$ 9,604	$ 11,263	$ 9,604
Issuance of common stock (in shares)	2,364,147	839,099	1,498,981	3,036,237	1,100,000	2,527,458
Issuance of common stock	$ 591	$ 210	$ 375	$ 759	$ 275	$ 632
Cancellation of treasury shares						$ (585)
Issuance of common stock under restricted stock plan, net of forfeitures (in shares)	500	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)	(6,216)		(46,581)
Common stock withheld for payroll taxes upon vesting of restricted stock			$ (18)	$ (2)		$ (12)
Ending balance (in shares)	50,051,332	47,686,685	46,837,511	42,981,139	39,951,118	38,839,918	50,051,332	42,981,139
Ending balance	$ 12,513	$ 11,922	$ 11,709	$ 10,745	$ 9,988	$ 9,710	$ 12,513	$ 10,745
Treasury Stock
Investment Company, Net Assets [Roll Forward]
Beginning balance	$ 0	$ 0	$ 0	$ 0	$ 0	$ (23,937)	$ 0	$ (23,937)
Beginning balance (in shares)	0	0	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	$ 0	$ 0
Ending balance (in shares)	0	0	0	0	0	0	0	0
Additional Paid-In Capital
Investment Company, Net Assets [Roll Forward]
Beginning balance	$ 855,177	$ 833,627	$ 796,945	$ 690,880	$ 667,440	$ 646,586	$ 796,945	$ 646,586
Issuance of common stock	52,324	20,027	37,403	64,768	22,218	44,240
Cancellation of treasury shares						(23,352)
Share-based compensation	1,544	1,538	1,224	1,188	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)	(136)		(914)
Change in restoration plan liability	(11)	(12)	(12)	(12)	(11)	(12)
Reclassification for certain permanent book-to-tax differences	(5,521)			(5,277)
Ending balance	903,513	855,177	833,627	751,411	690,880	667,440	903,513	751,411
Total Distributable Earnings (Loss)
Investment Company, Net Assets [Roll Forward]
Beginning balance	(75,841)	(68,005)	(52,532)	(43,094)	(40,949)	(41,845)	(52,532)	(41,845)
Dividends to shareholders	(31,532)	(30,520)	(29,508)	(26,858)	(24,769)	(22,916)
Reclassification for certain permanent book-to-tax differences	5,521			5,277
Net investment income	30,316	31,165	28,859	28,859	27,194	24,556
Net realized (loss) gain on investments			711	(7,842)		(12,782)
Net realized loss on investments and extinguishment of debt	(13,201)	(10,289)			29
Net unrealized appreciation (depreciation) on investments	(847)	1,808	(15,535)	2,467	(4,599)	12,038
Ending balance	$ (85,584)	$ (75,841)	$ (68,005)	$ (41,191)	$ (43,094)	$ (40,949)	$ (85,584)	$ (41,191)