Note 2 - Securities - Available for Sale Securities in a Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Total, fair value	$ 363,630	$ 77,323
Total, unrealized loss	3,465	162
Less than 12 months, fair value	349,109	76,060
Less than 12 months, unrealized loss	3,035	143
12 months or more, fair value	14,521	1,263
12 months or more, unrealized loss	430	19
US Treasury Securities [Member]
Total, fair value	75,384
Total, unrealized loss	205
Less than 12 months, fair value	75,384
Less than 12 months, unrealized loss	205
12 months or more, fair value	0
12 months or more, unrealized loss	0
US Government-sponsored Enterprises Debt Securities [Member]
Total, fair value	54,053	21,237
Total, unrealized loss	482	45
Less than 12 months, fair value	48,140	19,974
Less than 12 months, unrealized loss	302	26
12 months or more, fair value	5,913	1,263
12 months or more, unrealized loss	180	19
Collateralized Mortgage Backed Securities [Member]
Total, fair value	208,634	46,640
Total, unrealized loss	2,436	105
Less than 12 months, fair value	202,455	46,640
Less than 12 months, unrealized loss	2,302	105
12 months or more, fair value	6,179	0
12 months or more, unrealized loss	134	0
US States and Political Subdivisions Debt Securities [Member]
Total, fair value	17,869	3,456
Total, unrealized loss	282	2
Less than 12 months, fair value	15,440	3,456
Less than 12 months, unrealized loss	166	2
12 months or more, fair value	2,429	0
12 months or more, unrealized loss	116	0
Corporate Debt Securities [Member]
Total, fair value	7,690	5,990
Total, unrealized loss	60	10
Less than 12 months, fair value	7,690	5,990
Less than 12 months, unrealized loss	60	10
12 months or more, fair value	0	0
12 months or more, unrealized loss	$ 0	$ 0