Note 3 - Securities - Available for Sale Securities in a Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Total, fair value	$ 521,067	$ 604,414
Total, unrealized loss	56,319	71,066
Less than 12 months, fair value	3,448	187,643
Less than 12 months, unrealized loss	211	13,616
12 months or more, fair value	517,619	416,771
12 months or more, unrealized loss	56,108	57,450
US Treasury Securities [Member]
Total, fair value	123,767	139,427
Total, unrealized loss	7,964	12,606
Less than 12 months, fair value	0	10,824
Less than 12 months, unrealized loss	0	915
12 months or more, fair value	123,767	128,603
12 months or more, unrealized loss	7,964	11,691
US Government-sponsored Enterprises Debt Securities [Member]
Total, fair value	71,975	82,958
Total, unrealized loss	4,472	7,019
Less than 12 months, fair value	210	29,204
Less than 12 months, unrealized loss	0	1,920
12 months or more, fair value	71,765	53,754
12 months or more, unrealized loss	4,472	5,099
Collateralized Mortgage-Backed Securities [Member]
Total, fair value	256,615	293,929
Total, unrealized loss	35,827	42,301
Less than 12 months, fair value	111	96,758
Less than 12 months, unrealized loss	2	7,245
12 months or more, fair value	256,504	197,171
12 months or more, unrealized loss	35,825	35,056
US States and Political Subdivisions Debt Securities [Member]
Total, fair value	42,377	60,629
Total, unrealized loss	3,577	5,312
Less than 12 months, fair value	1,621	31,866
Less than 12 months, unrealized loss	15	980
12 months or more, fair value	40,756	28,763
12 months or more, unrealized loss	3,562	4,332
Corporate Debt Securities [Member]
Total, fair value	26,333	27,471
Total, unrealized loss	4,479	3,828
Less than 12 months, fair value	1,506	18,991
Less than 12 months, unrealized loss	194	2,556
12 months or more, fair value	24,827	8,480
12 months or more, unrealized loss	$ 4,285	$ 1,272