Note 3 - Securities - Available for Sale Securities in a Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Total, fair value	$ 510,918	$ 77,323
Total, unrealized loss	7,258	162
Less than 12 months, fair value	456,863	76,060
Less than 12 months, unrealized loss	5,194	143
12 months or more, fair value	54,055	1,263
12 months or more, unrealized loss	2,064	19
US Treasury Securities [Member]
Total, fair value	149,577	21,237
Total, unrealized loss	1,174	45
Less than 12 months, fair value	149,577	19,974
Less than 12 months, unrealized loss	1,174	26
12 months or more, fair value	0	1,263
12 months or more, unrealized loss	0	19
US Government-sponsored Enterprises Debt Securities [Member]
Total, fair value	73,640	46,640
Total, unrealized loss	931	105
Less than 12 months, fair value	63,042	46,640
Less than 12 months, unrealized loss	512	105
12 months or more, fair value	10,598	0
12 months or more, unrealized loss	419	0
Collateralized Mortgage Backed Securities [Member]
Total, fair value	253,444	3,456
Total, unrealized loss	4,525	2
Less than 12 months, fair value	213,292	3,456
Less than 12 months, unrealized loss	3,014	2
12 months or more, fair value	40,152	0
12 months or more, unrealized loss	1,511	0
US States and Political Subdivisions Debt Securities [Member]
Total, fair value	26,646	5,990
Total, unrealized loss	488	10
Less than 12 months, fair value	23,341	5,990
Less than 12 months, unrealized loss	354	10
12 months or more, fair value	3,305	0
12 months or more, unrealized loss	134	$ 0
Corporate Debt Securities [Member]
Total, fair value	7,611
Total, unrealized loss	140
Less than 12 months, fair value	7,611
Less than 12 months, unrealized loss	140
12 months or more, fair value	0
12 months or more, unrealized loss	$ 0