Note 15 - Fair Value Measurements and Fair Values of Financial Instruments - Quantitative Information about Level 3 Assets (Details) $ in Thousands		Dec. 31, 2019 USD ($)		Dec. 31, 2018 USD ($)
Valuation Technique, Discounted Cash Flow [Member] | Corporate Debt Securities [Member]
Fair Value		$ 2,820		$ 3,069
Valuation Technique, Discounted Cash Flow [Member] | Corporate Debt Securities [Member] | Measurement Input, Discount Rate [Member]
Securities, unobservable input		(0.0666)		(0.0824)
Valuation Technique, Discounted Cash Flow [Member] | Corporate Debt Securities [Member] | Measurement Input, Discount Rate [Member] | Minimum [Member]
Securities, unobservable input		(0.0666)		(0.0824)
Valuation Technique, Discounted Cash Flow [Member] | Corporate Debt Securities [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member]
Securities, unobservable input		(0.0666)		(0.0824)
Valuation Technique, Discounted Cash Flow [Member] | Corporate Debt Securities [Member] | Measurement Input, Discount Rate [Member] | Weighted Average [Member]
Securities, unobservable input		(0.0666)		(0.0824)
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member]
Fair Value		$ 4,447		$ 4,785
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Discount Rate [Member]
SBA servicing assets, unobservable input		(0.1075)		(0.115)
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Discount Rate [Member] | Minimum [Member]
SBA servicing assets, unobservable input		(0.1075)		(0.115)
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member]
SBA servicing assets, unobservable input		(0.1075)		(0.115)
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Prepayment Rate [Member]
SBA servicing assets, unobservable input		(0.1353)		(0.1031)
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Prepayment Rate [Member] | Minimum [Member]
SBA servicing assets, unobservable input		(0.1353)		(0.1031)
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Prepayment Rate [Member] | Maximum [Member]
SBA servicing assets, unobservable input		(0.1353)		(0.1031)
Valuation Technique, Discounted Cash Flow [Member] | SBA Servicing Assets [Member] | Measurement Input, Prepayment Rate [Member] | Weighted Average [Member]
SBA servicing assets, unobservable input		(0.1353)		(0.1031)
Valuation, Market Approach [Member] | Impaired Loans [Member]
Fair Value	[2]	$ 5,730	[1]	$ 5,955
Valuation, Market Approach [Member] | Impaired Loans [Member] | Measurement Input, Liquidation Expenses [Member] | Minimum [Member]
Impaired loans, unobservable input	[1],[3]	0.09		0.11
Valuation, Market Approach [Member] | Impaired Loans [Member] | Measurement Input, Liquidation Expenses [Member] | Maximum [Member]
Impaired loans, unobservable input	[1],[3]	0.2		0.24
Valuation, Market Approach [Member] | Impaired Loans [Member] | Measurement Input, Liquidation Expenses [Member] | Weighted Average [Member]
Impaired loans, unobservable input	[3]	(0.12)		(0.13)
Valuation, Market Approach [Member] | Other Real Estate Owned [Member]
Fair Value	[2]	$ 899		$ 1,114
Valuation, Market Approach [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Minimum [Member]
Other real estate owned, measurement input		0.06
Valuation, Market Approach [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Maximum [Member]
Other real estate owned, measurement input		0.16
Valuation, Market Approach [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Weighted Average [Member]
Other real estate owned, measurement input	[3]	(0.08)
Appraised Value of Collateral [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member]
Other real estate owned, measurement input	[1],[3]			(0.73)
Appraised Value of Collateral [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Minimum [Member]
Other real estate owned, measurement input				(0.73)
Appraised Value of Collateral [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Maximum [Member]
Other real estate owned, measurement input				(0.73)
Appraised Value of Collateral [Member] | Other Real Estate Owned [Member] | Measurement Input, Liquidation Expenses [Member] | Weighted Average [Member]
Other real estate owned, measurement input				(0.73)

[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.