Note 6 - Fair Values of Assets and Liabilities - Quantitative Information about Level 3 Assets and Liabilities Fair Value Measurements (Details) $ in Thousands	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Loans, interest and fees receivable, at fair value	$ 4,386	$ 6,306
Notes Payable Associated with Structured Financings, Fair Value	3,920	5,651
Valuation Technique, Discounted Cash Flow [Member]
Notes Payable Associated with Structured Financings, Fair Value	3,920	5,651
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member]
Loans, interest and fees receivable, at fair value	$ 4,386	$ 6,306
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.275	0.258
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.594	0.308
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.31	0.264
Notes payable associated with structured financings, measurement input	0.275	0.258
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.022	0.022
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.055	0.03
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.026	0.023
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.105	0.087
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.394	0.113
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.137	0.09
Notes payable associated with structured financings, measurement input	0.105	0.087
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Prepayment Rate [Member] | Weighted Average [Member]
Notes payable associated with structured financings, measurement input	0.022	0.022
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.113	0.149
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.169	0.195
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.119	0.155
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.143	0.149
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.143	0.149
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.143	0.149
Notes payable associated with structured financings, measurement input	0.143	0.149