Note 6 - Fair Values of Assets and Liabilities - Quantitative Information about Level 3 Assets and Liabilities Fair Value Measurements (Details) $ in Thousands	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Loans, interest and fees receivable, at fair value	$ 5,394	$ 6,306
Notes Payable Associated with Structured Financings, Fair Value	4,776	5,651
Valuation Technique, Discounted Cash Flow [Member]
Notes Payable Associated with Structured Financings, Fair Value	4,776	5,651
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member]
Loans, interest and fees receivable, at fair value	$ 5,394	$ 6,306
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.252	0.258
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.335	0.308
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Gross Yield [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.263	0.264
Notes payable associated with structured financings, measurement input	0.252	0.258
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.021	0.022
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.031	0.03
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.022	0.023
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Prepayment Rate [Member] | Weighted Average [Member]
Notes payable associated with structured financings, measurement input	0.021	0.022
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.106	0.087
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.112	0.113
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Default Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.107	0.09
Notes payable associated with structured financings, measurement input	0.106	0.087
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.156	0.149
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.209	0.195
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Servicing Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.163	0.155
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Minimum [Member]
Loans and fees receivable, measurement input	0.149	0.149
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member]
Loans and fees receivable, measurement input	0.149	0.149
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member] | Weighted Average [Member]
Loans and fees receivable, measurement input	0.149	0.149
Notes payable associated with structured financings, measurement input	0.149	0.149