Note 8 - Loans - Troubled Debt Restructuring Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Charge-offs	$ 0	$ (811)	$ 0	$ (811)
Accruing Troubled Debt Restructuring [Member]
Beginning balance	34,364	62,948	35,336	65,071
New restructurings	1,900	13,244	2,434	15,192
Payments	(4,593)	(9,998)	(6,099)	(14,069)
Restructured loans placed on non-accrual status	0	(1,296)	0	(1,296)
New restructurings	1,900	13,244	2,434	15,192
Ending balance	31,671	64,898	31,671	64,898
Non-accruing Troubled Debt Restructuring [Member]
Beginning balance	17,889	23,301	18,048	24,189
New restructurings	0	3,160	0	3,160
Payments	(249)	(4,489)	(408)	(4,970)
Restructured loans placed on non-accrual status	0	1,296	0	1,296
New restructurings	0	3,160	0	3,160
Charge-offs	(4,970)	(811)	(4,970)	(1,218)
Ending balance	$ 12,670	$ 22,457	$ 12,670	$ 22,457