Note 8 - Loans - Troubled Debt Restructuring Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Charge-offs	$ 0	$ 0	$ 0	$ 0
Accruing Troubled Debt Restructuring [Member]
Beginning balance	27,864	34,364	27,721	35,336
New restructurings	0	1,900	686	2,434
Payments	(603)	(4,593)	(1,146)	(6,099)
Ending balance	27,261	31,671	27,261	31,671
Non-accruing Troubled Debt Restructuring [Member]
Beginning balance	8,661	17,889	8,985	18,048
Payments	(259)	(249)	(583)	(408)
Charge-offs	0	(4,970)	0	(4,970)
Ending balance	$ 8,402	$ 12,670	$ 8,402	$ 12,670