Financial Highlights - Schedule of Financial Highlights (Details) - USD ($)		3 Months Ended												9 Months Ended		12 Months Ended
		Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022		Dec. 31, 2023		Mar. 31, 2022		Mar. 31, 2021		Mar. 31, 2020		Mar. 12, 2020
Investment Company, Financial Highlights [Abstract]
Net asset value at beginning of period					$ 15.1			$ 15.79				$ 15.88		$ 15.79		$ 15.1		$ 15.88		$ 15.7		$ 19.06
Net investment income		$ 0.46	$ 0.43	$ 0.44	0.45	$ 0.43	$ 0.35	0.37	$ 0.42	$ 0.35	$ 0.33	0.39	$ 0.39	1.15	[1]	1.78	[1]	1.49	[1]	1.69	[1]	2.16	[1]
Net realized and change in unrealized gains (losses)		0.05	0.03	(0.05)	0.01	(0.41)	(0.1)	(0.28)	(0.36)	(0.03)	0.06	0.1	0.26	(0.79)	[1]	0.04	[1]	(0.21)	[1]	0.03	[1]	(3.89)	[1]
Net increase in net assets resulting from operations		0.51	$ 0.46	$ 0.39	$ 0.46	0.02	$ 0.25	$ 0.09	0.07	$ 0.32	$ 0.39	$ 0.49	0.65	0.36		1.82		1.28		1.71		(1.73)
Distribution of net investment income	[2]													(1.05)		(1.52)		(1.44)		(1.53)		(1.8)
Distribution of return of capital	[2]													0		0		0		0		0
Accretion due to share repurchases														0.01		0.01		0.07		0		0.2
Net asset value at end of period		15.41				15.1			15.79				$ 15.88	15.1		15.41		15.79		$ 15.88		15.7
Per share market value at end of period		$ 13.68				$ 11.4			$ 13.22					$ 11.4		$ 13.68		$ 13.22				$ 13.72		$ 6.75
Total return	[3]													(5.42%)		34.90%		7.19%		135.08%		(48.62%)
Shares outstanding at end of period		65,253,275				65,451,359			63,647,240				65,259,176	65,451,359		65,253,275		63,647,240		65,259,176		65,259,176
Weighted average shares outstanding														64,585,966		65,330,350		64,516,533		65,259,176		67,228,771
Net assets at end of period (in millions)		$ 1,005,310,000				$ 988,106,000			$ 1,004,832,000				$ 1,036,330,000	$ 988,106,000		$ 1,005,310,000		$ 1,004,832,000		$ 1,036,330,000		$ 1,024,300,000
Annualized ratio of operating expenses to average net assets	[4],[5]													5.67%		5.76%		6.04%		5.05%		4.79%
Annualized ratio of interest and other debt expenses to average net assets	[4]													7.83%		10.37%		5.34%		5.44%		6.01%
Annualized ratio of total expenses to average net assets	[4],[5]													13.50%		16.13%		11.38%		10.49%		10.80%
Annualized ratio of net investment income to average net assets	[4]													9.87%		11.66%		9.32%		10.82%		11.91%
Average debt outstanding (in millions)														$ 1,546,000,000		$ 1,453,700,000		$ 1,545,200,000		$ 1,632,300,000		$ 1,529,500,000
Average debt per share														$ 23.94		$ 22.25		$ 23.95		$ 25.01		$ 22.75
Annualized portfolio turnover rate	[4]													26.70%		17.53%		42.41%		23.79%		46.58%
Asset coverage per unit	[6]													$ 1,648		$ 1,684		$ 1,635		$ 1,705		$ 1,567

[1] Financial highlights are based on the weighted average number of shares outstanding for the period presented.

[2] The tax character of distributions are determined based on taxable income calculated in accordance with income tax regulations which may differ from amounts determined under GAAP. Although the tax character of distributions paid to stockholders through December 31, 2023 may include return of capital, the exact amount cannot be determined at this point. Per share amounts are based on actual rate per share.

[3] Total return is based on the change in market price per share during the respective periods. Total return also takes into account distributions, if any, reinvested in accordance with the Company’s dividend reinvestment plan.

[4] Annualized for the nine months ended December 31, 2022.

[5] The ratio of operating expenses to average net assets and the ratio of total expenses to average net assets are shown inclusive of all voluntary management and incentive fee waivers (See Note 4 to the consolidated financial statements). For the twelve months ended December 31, 2023, the ratio of operating expenses to average net assets and the ratio of total expenses to average net assets would be 5.82% and 16.29%, respectively, without the voluntary fee waivers. For the nine months ended December 31, 2022, the ratio of operating expenses to average net assets and the ratio of total expenses to average net assets would be 5.73% and 13.63%, respectively, without the voluntary fee waivers. For the year ended March 31, 2022, the ratio of operating expenses to average net assets and the ratio of total expenses to average net assets would be 6.10% and 11.44%, respectively, without the voluntary fee waivers. For the year ended March 31, 2021, the ratio of operating expenses to average net assets and the ratio of total expenses to average net assets would be 5.08% and 10.53%, respectively, without the voluntary fee waivers. For the year ended March 31, 2020, the ratio of operating expenses to average net assets and the ratio of total expenses to average net assets would be 4.81% and 10.83%, respectively, without the voluntary fee waivers.

[6] The asset coverage ratio for a class of senior securities representing indebtedness is calculated as our total assets, less all liabilities and indebtedness not represented by senior securities, divided by senior securities representing indebtedness. This asset coverage ratio is multiplied by one thousand to determine the asset coverage per unit. As of December 31, 2023 and December 31, 2022, the Company's asset coverage was 168% and 165%, respectively.