Note 15 - Fair Value Measurements and Fair Values of Financial Instruments - Quantitative Information about Level 3 Assets (Details) $ in Thousands		Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Valuation Technique, Discounted Cash Flow [Member] | Corporate Debt Securities [Member]
Fair Value		$ 2,631	$ 2,820
Valuation Technique, Discounted Cash Flow [Member] | Corporate Debt Securities [Member] | Measurement Input, Discount Rate [Member]
Corporate bonds		0.0348
Valuation Technique, Discounted Cash Flow [Member] | Corporate Debt Securities [Member] | Measurement Input, Discount Rate [Member] | Weighted Average [Member]
Corporate bonds			0.0666
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member]
Fair Value		$ 4,626	$ 4,447
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Discount Rate [Member] | Weighted Average [Member]
SBA servicing assets		0.1000	0.1075
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Conditional Prepayment Rate [Member] | Weighted Average [Member]
SBA servicing assets		0.1322	0.1353
Valuation, Market Approach [Member] | Impaired Loans [Member]
Fair Value	[1],[2]	$ 5,678	$ 5,730
Valuation, Market Approach [Member] | Impaired Loans [Member] | Measurement Input, Liquidation Expenses [Member] | Weighted Average [Member]
Impaired loans	[3]	0.12	0.12
Valuation, Market Approach [Member] | Impaired Loans [Member] | Measurement Input, Liquidation Expenses [Member] | Minimum [Member]
Impaired loans	[3]	0	0.09
Valuation, Market Approach [Member] | Impaired Loans [Member] | Measurement Input, Liquidation Expenses [Member] | Maximum [Member]
Impaired loans	[3]	0.23	0.20
Valuation, Market Approach [Member] | Other Real Estate Owned [Member]
Fair Value	[1],[2]	$ 364	$ 899
Valuation, Market Approach [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Weighted Average [Member]
Other real estate owned	[3]	0.13	0.08
Valuation, Market Approach [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Minimum [Member]
Other real estate owned	[3]	0.07	0.06
Valuation, Market Approach [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Maximum [Member]
Other real estate owned	[3]	0.16	0.16

[1] Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses.

[2] Fair value is generally determined through independent appraisals of the underlying collateral, which include Level 3 inputs that are not identifiable.

[3] The range and weighted average of qualitative factors such as economic conditions and estimated liquidation expenses are presented as a percent of the appraised value.