Agreements and Related Party Transactions - Additional Information (Details) - USD ($)			1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Apr. 15, 2011	Nov. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Related Party Transaction [Line Items]
Management fees				$ 11,928,000	$ 10,330,000	$ 34,071,000	$ 29,148,000
Incentive fees realized and payable to advisor				11,151,000	7,882,000	31,139,000	22,483,000
Administration Agreement
Related Party Transaction [Line Items]
Agreement termination period			60 days
Administration Agreement | Adviser | Other General and Administrative Expenses
Related Party Transaction [Line Items]
Expenses incurred				900,000	800,000	2,100,000	2,200,000
Investment Advisory Agreement
Related Party Transaction [Line Items]
Percentage of management fee on gross assets		1.50%
Management fees				11,900,000	10,300,000	34,100,000	29,100,000
Percentage of excess pre-incentive fee net investment income for immediate preceding calendar quarter		100.00%
Percentage of hurdle rate		1.50%
Percentage of total pre-Incentive fee net investment income payable quarterly		17.50%
Percentage of excess pre-Incentive Fee net investment income quarterly		1.82%
Percentage of all remaining pre-Incentive Fee net investment income quarterly		17.50%
Percentage of excess catch-up provision for pre-Incentive Fee net investment income		100.00%
Percentage of all pre-Incentive Fee net investment income		17.50%
Percentage of pre-Incentive Fee net investment income annualized		7.28%
Percentage of excess pre-Incentive Fee net investment income		17.50%
Percentage of pre-Incentive Fee net investment income payable in any quarter		1.82%
Percentage of weighted cumulative realized capital gains less cumulative realized capital losses and unrealized capital losses		15.00%
Incentive fees				13,700,000	7,900,000	36,200,000	14,800,000
Incentive fees realized and payable to advisor				11,200,000	7,900,000	31,100,000	22,500,000
Incentive fees accrued related to expense (reversal) of capital gains fees				2,600,000	100,000	5,100,000	7,700,000
Investment Advisory Agreement | Capital Gains Accrue Following March 31, 2014
Related Party Transaction [Line Items]
Percentage of incentive fee rate		17.50%
Investment Advisory Agreement | Realized Capital Gains Accrued Prior to March 31, 2014
Related Party Transaction [Line Items]
Percentage of incentive fee rate		15.00%
Investment Advisory Agreement | Realized Capital Gains Accrued Beginning April 1, 2014
Related Party Transaction [Line Items]
Percentage of incentive fee rate		17.50%
Investment Advisory Agreement | Future Realized Capital Gains Prior to April 1, 2014
Related Party Transaction [Line Items]
Incentive fee rate	17.50%
Remaining investments	$ 0
Investment Advisory Agreement | Leverage Waiver
Related Party Transaction [Line Items]
Management fees				$ 300,000	$ 200,000	$ 800,000	$ 200,000
Percentage of asset coverage		200.00%
Percentage of management fee in excess of annual rate on gross assets		1.00%
Percentage of management fee in excess of quarter rate on gross assets		0.25%