Note 8 - Loans - Accruing Troubled Debt Restructurings (Details) - Accruing Troubled Debt Restructuring [Member] - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Accruing TDRs	$ 27,864	$ 27,721	$ 34,364	$ 35,336
Payment Deferral [Member]
Accruing TDRs	6,754	6,222
Contractual Interest Rate Reduction [Member]
Accruing TDRs	5,869	5,910
Rate Reduction and Payment Deferral [Member]
Accruing TDRs	15,241	15,589
Commercial Portfolio Segment [Member]
Accruing TDRs	4,544	3,983
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	4,544	3,983
Commercial Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	0	0
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	0	0
Commercial Real Estate Portfolio Segment [Member]
Accruing TDRs	19,453	19,575
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	524	515
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	5,607	5,635
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	13,322	13,425
Residential Portfolio Segment [Member]
Accruing TDRs	3,867	4,163
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	1,686	1,724
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	262	275
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	$ 1,919	$ 2,164