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Note 7 - Borrowings (Details Textual) $ / shares in Units, $ in Thousands										3 Months Ended		9 Months Ended
	Sep. 04, 2025 USD ($)	May 23, 2025 USD ($)	Apr. 25, 2025	Apr. 17, 2025	Oct. 17, 2024 USD ($)	Jun. 21, 2024 USD ($)	Jun. 20, 2024	Jun. 19, 2024	May 24, 2023 USD ($)	Sep. 30, 2025 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2025 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) $ / shares	Dec. 31, 2024 USD ($) $ / shares	Dec. 31, 2023 $ / shares	Jun. 29, 2023 USD ($)	Nov. 09, 2022 USD ($)	Jun. 15, 2022 USD ($) $ / shares	Mar. 30, 2021 USD ($) $ / shares	Apr. 21, 2020 USD ($)
Asset Coverage to Borrowings, Ratio, Percent												174.00%
Restricted Investments										$ 2,417		$ 2,417		$ 3,338
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net										4,719		4,719		4,174
Long-Term Debt, Gross										428,750		428,750		472,078
Debt Instrument, Face Amount										$ 757,750		757,750		$ 716,078
Proceeds from Convertible Debt												$ 40,000	$ 0
Share Price (in dollars per share) | $ / shares										$ 6.1	$ 10.65	$ 6.1	$ 10.65	$ 8.99	$ 13.17
Debt Conversion, Original Debt, Amount												$ 17,250	$ 0
Debt Instrument, Convertible, Accelerated Unamortized Debt Issuance Costs										$ 400		1,200
Conversion of 2031 Notes Into Common Stock [Member]
Debt Conversion, Original Debt, Amount										$ 4,800		$ 17,300
Debt Conversion, Converted Instrument, Shares Issued (in shares) | shares										643,043		2,264,546
Debt Instrument, Convertible, Weighted Average Conversion Price (in dollars per share) | $ / shares										$ 7.43		$ 7.69
Key Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity, Accordian Feature																$ 150,000
Line of Credit Facility, Maximum Borrowing Capacity																$ 300,000
Line of Credit Facility, Advance Rate of Eligible Debt Investments																60.00%
Long-Term Debt, Weighted Average Interest Rate, over Time										7.56%	8.53%	7.59%	8.67%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage												0.75%
Line of Credit Facility, Current Borrowing Capacity										$ 150,000		$ 150,000		$ 150,000
Line of Credit Facility, Remaining Borrowing Capacity										42,000		42,000		24,800
Long-Term Debt, Gross										0		0		0
Debt Instrument, Face Amount										$ 150,000		$ 150,000		$ 150,000
Key Facility [Member] | Prime Rate [Member]
Debt Instrument, Basis Spread on Variable Rate							0.10%	0.25%
Debt Instrument, Variable Rate										7.25%		7.25%		7.50%
NYL Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity									$ 250,000											$ 100,000
Line of Credit Facility, Current Borrowing Capacity										$ 69,000		$ 69,000		$ 69,000
Line of Credit Facility, Remaining Borrowing Capacity										8,900		8,900		8,400
Line of Credit Facility, Maximum Borrowing Capacity, Accordion Feature																				$ 200,000
Line of Credit Facility, Advance Rate																				67.00%
Line of Credit Facility, Change in Maximum Borrowing Capacity									$ 50,000
Debt Instrument, Interest Rate, Stated Percentage									4.60%
Long-Term Line of Credit										$ 181,000		$ 181,000		$ 181,000
Line of Credit Facility, Interest Rate at Period End										6.57%		6.57%		6.43%
Restricted Investments										$ 1,400		$ 1,400		$ 1,400
Long-Term Debt, Gross										181,000		181,000		181,000
Debt Instrument, Face Amount										250,000		250,000		250,000
NYL Facility [Member] | Three Year I Curve [Member]
Debt Instrument, Basis Spread on Variable Rate			2.95%
Nuveen Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity, Accordian Feature						$ 200,000
Line of Credit Facility, Maximum Borrowing Capacity		$ 200,000				$ 100,000
Line of Credit Facility, Current Borrowing Capacity										110,000		110,000		25,000
Line of Credit Facility, Remaining Borrowing Capacity										600		600		9,900
Line of Credit Facility, Advance Rate						67.50%
Line of Credit Facility, Change in Maximum Borrowing Capacity		$ 100,000
Long-Term Line of Credit										$ 90,000		$ 90,000		$ 75,000
Line of Credit Facility, Interest Rate at Period End										7.21%		7.21%		7.38%
Restricted Investments										$ 1,100		$ 1,100		$ 1,000
Long-Term Debt, Gross										90,000		90,000		75,000
Debt Instrument, Face Amount										200,000		200,000		100,000
Nuveen Facility [Member] | Selected Interest Rates (Daily) [Member]
Debt Instrument, Basis Spread on Variable Rate		2.95%				3.15%
Asset-backed Notes 2022 [Member]
Debt Instrument, Interest Rate, Stated Percentage																	7.56%
Restricted Investments														1,000
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net										900		900
Long-Term Debt, Gross										0		0		81,078
Debt Instrument, Face Amount										0		0		81,078			$ 157,800
The 2026 Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage																			4.875%
Long-Term Debt, Gross										57,500		57,500		57,500
Debt Instrument, Face Amount										57,500		57,500		57,500					$ 57,500
The 2026 Notes Underwriter Option [Member]
Debt Instrument, Face Amount																			$ 7,500
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares																			$ 25
The 2027 Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage																		6.25%
Long-Term Debt, Gross										57,500		57,500		57,500
Debt Instrument, Face Amount										57,500		57,500		57,500				$ 50,000
The 2027 Notes Underwriter Option [Member]
Debt Instrument, Face Amount																		$ 7,500
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares																		$ 25
The 2031 Convertible Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage					7.125%
Long-Term Debt, Gross										2,750		2,750		20,000
Debt Instrument, Face Amount					$ 20,000					$ 2,750		$ 2,750		20,000
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares										$ 6.75		$ 6.75
Proceeds from Convertible Debt					$ 18,600
Debt Instrument, Maturity Date					Oct. 17, 2031
Debt Instrument, Interest Rate, Increase From Failure to Maintain Investment Rating					1.00%
Debt Instrument, Interest Rate, Increase From Default					2.00%
Debt Instrument, Redemption Price, Percentage				100.00%	100.00%
Debt Instrument, Convertible, Threshold Consecutive Trading Days										5		5
Debt Instrument, Convertible, Number of Equity Instruments												407,407
Debt Instrument, Convertible, Maximum Beneficial Ownership Percentage					4.99%
Convertible Debt										$ 2,800	$ 0	$ 2,800	$ 0	20,000
The 2030 Convertible Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage	5.50%
Long-Term Debt, Gross										40,000		40,000		0
Debt Instrument, Face Amount	$ 40,000									$ 40,000		$ 40,000		0
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares										$ 6.75		$ 6.75
Proceeds from Convertible Debt	$ 36,600
Debt Instrument, Maturity Date	Sep. 04, 2030
Debt Instrument, Redemption Price, Percentage	100.00%
Debt Instrument, Convertible, Threshold Consecutive Trading Days	5									5		5
Debt Instrument, Convertible, Number of Equity Instruments												5,925,926
Debt Instrument, Convertible, Maximum Beneficial Ownership Percentage	4.99%
Convertible Debt										$ 40,000		$ 40,000		$ 0
Minimum [Member]
Asset Coverage to Borrowings, Ratio, Percent												150.00%
Minimum [Member] | Key Facility [Member] | Prime Rate [Member]
Debt Instrument, Basis Spread on Variable Rate							4.10%	4.25%
Minimum [Member] | Nuveen Facility [Member]
Debt Instrument, Interest Rate, Stated Percentage		5.00%				5.00%
Minimum [Member] | Nuveen Facility [Member] | Selected Interest Rates (Daily) [Member]
Debt Instrument, Basis Spread on Variable Rate, Treasury Yield Maturity (Year)						3 years
Maximum [Member] | Nuveen Facility [Member] | Selected Interest Rates (Daily) [Member]
Debt Instrument, Basis Spread on Variable Rate, Treasury Yield Maturity (Year)						5 years
Weighted Average [Member] | Nuveen Facility [Member] | Selected Interest Rates (Daily) [Member]
Debt Instrument, Basis Spread on Variable Rate, Treasury Yield Maturity (Year)						4 years 10 months 17 days

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The asset coverage to borrowings ratio percentage.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

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Investments which are not defined as or included in marketable (debt, equity, or other) securities whose use is restricted in whole or in part, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet.

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Price of a single share of a number of saleable stocks of a company.

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