Note 6 - Securities - Securities Available-for-sale (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Amortized cost	$ 985,599	$ 1,022,443
Gross unrealized gains	303	8,160
Gross unrealized losses	95,151	9,542
Fair value	890,751	1,021,061
US Treasury Securities [Member]
Amortized cost	32,783	22,751
Gross unrealized gains	0	0
Gross unrealized losses	2,668	437
Fair value	30,115	22,314
US Government Agencies Debt Securities [Member]
Amortized cost	50,288	27,867
Gross unrealized gains	0	2
Gross unrealized losses	2,916	376
Fair value	47,372	27,493
Corporate Debt Securities [Member]
Amortized cost	48,475	45,876
Gross unrealized gains	25	812
Gross unrealized losses	2,496	106
Fair value	46,004	46,582
Collateralized Mortgage-Backed Securities [Member]
Amortized cost	506,671	555,528
Gross unrealized gains	267	3,246
Gross unrealized losses	55,213	6,435
Fair value	451,725	552,339
US States and Political Subdivisions Debt Securities [Member]
Amortized cost	347,382	370,421
Gross unrealized gains	11	4,100
Gross unrealized losses	31,858	2,188
Fair value	$ 315,535	$ 372,333

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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