Note 15 - Fair Value Measurements - Quantitative Information (Details) - Fair Value, Inputs, Level 3 [Member] - Fair Value, Recurring [Member] $ in Thousands	Dec. 31, 2020 USD ($)
Corporate Debt Securities [Member] | Valuation, Market Approach [Member]
Assets, fair value	$ 1,540
Corporate Debt Securities [Member] | Valuation, Market Approach [Member] | Minimum [Member] | Measurement Input, Quoted Price [Member]
Measurement input	0.89	[1]
Corporate Debt Securities [Member] | Valuation, Market Approach [Member] | Maximum [Member] | Measurement Input, Quoted Price [Member]
Measurement input	0.91	[1]
Corporate Debt Securities [Member] | Valuation Technique, Discounted Cash Flow [Member]
Assets, fair value	$ 1,000
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Valuation, Market Approach [Member]
Assets, fair value	$ 6,372
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Valuation, Market Approach [Member] | Minimum [Member] | Measurement Input, Quoted Price [Member]
Measurement input	1.04	[1]
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Valuation, Market Approach [Member] | Maximum [Member] | Measurement Input, Quoted Price [Member]
Measurement input	1.07	[1]

[1] Unobservable inputs were weighted by the relative fair value of the instruments.