Note 6 - Fair Values of Assets and Liabilities - Quantitative Information about Level 3 Assets and Liabilities Fair Value Measurements (Details) $ in Thousands	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Loans, interest and fees receivable, at fair value	$ 2,049,993	$ 1,817,976
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member]
Loans, interest and fees receivable, at fair value	$ 2,049,993	$ 1,817,976
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.266	0.247
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.384	0.361
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.336	0.316
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.09	0.05
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.099	0.114
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.095	0.103
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.311	0.092
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.348	0.303
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.326	0.302
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.03	0.035
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.03	0.064
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.03	0.036
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.06	0.098
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.225	0.105
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.107	0.101