Note 8 - Loans - Non-accrual Troubled Debt Restructurings (Details) - Non-accruing Troubled Debt Restructuring [Member] - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Accruing TDRs	$ 8,402	$ 8,661	$ 8,985	$ 12,670	$ 17,889	$ 18,048
Payment Deferral [Member]
Accruing TDRs	8,402		8,985
Contractual Interest Rate Reduction [Member]
Accruing TDRs	0		0
Rate Reduction and Payment Deferral [Member]
Accruing TDRs	0		0
Commercial Portfolio Segment [Member]
Accruing TDRs	7,903		8,462
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	7,903		8,462
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
Residential Portfolio Segment [Member]
Accruing TDRs	499		523
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	499		523
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	0		0
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	$ 0		$ 0