Note 3 - Securities - Securities Available-for-sale (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Securities available-for-sale, amortized costs	$ 680,496	$ 697,786
Securities available-for-sale, gross unrealized gains	24	0
Securities available-for-sale, gross unrealized losses	78,622	79,185
Securities available-for-sale, fair values	601,898	618,601
US Government Agencies Debt Securities [Member]
Securities available-for-sale, amortized costs	351,136	353,904
Securities available-for-sale, gross unrealized gains	0	0
Securities available-for-sale, gross unrealized losses	40,012	42,060
Securities available-for-sale, fair values	311,124	311,844
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale, amortized costs	178,106	179,507
Securities available-for-sale, gross unrealized gains	0	0
Securities available-for-sale, gross unrealized losses	32,372	29,614
Securities available-for-sale, fair values	145,734	149,893
Collateralized Mortgage-Backed Securities [Member]
Securities available-for-sale, amortized costs	143,747	156,875
Securities available-for-sale, gross unrealized gains	24	0
Securities available-for-sale, gross unrealized losses	5,473	6,724
Securities available-for-sale, fair values	138,298	150,151
Corporate Debt Securities [Member]
Securities available-for-sale, amortized costs	6,507	6,504
Securities available-for-sale, gross unrealized gains	0	0
Securities available-for-sale, gross unrealized losses	764	754
Securities available-for-sale, fair values	5,743	5,750
US Treasury Securities [Member]
Securities available-for-sale, amortized costs	1,000	996
Securities available-for-sale, gross unrealized gains	0	0
Securities available-for-sale, gross unrealized losses	1	33
Securities available-for-sale, fair values	$ 999	$ 963