Borrowings - Narrative (Details)		3 Months Ended
	Apr. 06, 2022 USD ($)	Mar. 31, 2025 USD ($) lender	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)
Debt Instrument [Line Items]
Commitments available, net		$ 325,000,000		$ 325,000,000
Revolving credit facility		88,000,000		88,000,000
Deferred credit facility costs		1,777,000		2,019,000
Fair value of the reporting date		162,796,000		160,277,000
Level 3
Debt Instrument [Line Items]
Fair value of the reporting date		162,796,000		160,277,000
2027 Notes | Unsecured Debt
Debt Instrument [Line Items]
Face amount	$ 75,000,000.0
Interest rate	5.86%
2027 Notes | Senior Notes
Debt Instrument [Line Items]
Commitments available, net		75,000,000		75,000,000
Aggregate principal balance, secured status threshold	$ 25,000,000
Asset coverage ratio, minimum	1.50
Interest coverage ratio, minimum	1.25
Minimum stockholders' equity balance	$ 142,800,000
Upward adjustment, percent of issuance proceeds	65.00%
Deferred issuance costs		$ 400,000		500,000
Debt term		5 years
2027 Notes | Senior Notes | Level 3
Debt Instrument [Line Items]
Fair value of the reporting date		$ 74,800,000		72,300,000
2027 Notes | Senior Notes | Internal Noninvestment Grade
Debt Instrument [Line Items]
Interest rate	6.86%
Revolving Credit Facility | Credit Facility | Line of Credit
Debt Instrument [Line Items]
Commitments available, net		$ 250,000,000.0		250,000,000
Number of lenders | lender		4
Accordion feature, higher borrowing capacity option		$ 400,000,000.0
Advance rate		55.00%
Debt instrument, variable interest rate, type flag		Secured Overnight Financing Rate (SOFR) [Member]
Basis spread on variable rate		0.50%
Revolving credit facility		$ 88,000,000		88,000,000
Deferred credit facility costs		1,800,000		2,000,000
Credit facility, average outstanding borrowings		$ 88,000,000.0	$ 87,500,000
Credit facility, average interest rate		7.56%	8.58%
Assets pledged as collateral		$ 239,300,000		260,800,000
Fair value of the reporting date		88,000,000		88,000,000
Revolving Credit Facility | Credit Facility | Line of Credit | Level 3
Debt Instrument [Line Items]
Fair value of the reporting date		$ 88,000,000		$ 88,000,000
Revolving Credit Facility | Credit Facility | Line of Credit | Revolving Period
Debt Instrument [Line Items]
Basis spread on variable rate		3.25%
Revolving Credit Facility | Credit Facility | Line of Credit | Amortization Period
Debt Instrument [Line Items]
Basis spread on variable rate		4.25%