Note 6 - Fair Value Measurements and Fair Value of Financial Instruments - Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Securities available-for-sale	$ 675,941	$ 534,507
Reported Value Measurement [Member]
Cash and due from banks	299,320	265,536
Securities available-for-sale	675,941	534,507
Restricted investments in bank stocks	47,287	27,826
Equity securities	15,993	13,794
Net loans	7,191,834	6,749,849
Derivatives	31,285	3,347
Accrued interest receivable	34,615	34,152
Noninterest-bearing deposits	1,712,875	1,617,049
Interest-bearing deposits	4,904,724	4,715,904
Borrowings	874,964	468,193
Subordinated debentures	153,103	152,951
Accrued interest payable	3,120	2,716
Estimate of Fair Value Measurement [Member]
Cash and due from banks	299,320	265,536
Securities available-for-sale	675,941	534,507
Equity securities	15,993	13,794
Net loans	6,993,635	6,800,287
Derivatives	31,285	3,347
Accrued interest receivable	34,615	34,152
Noninterest-bearing deposits	1,712,875	1,617,049
Interest-bearing deposits	4,871,665	4,716,358
Borrowings	872,176	469,671
Subordinated debentures	153,952	163,995
Accrued interest payable	3,120	2,716
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and due from banks	299,320	265,536
Securities available-for-sale	494	195
Equity securities	14,053	11,081
Net loans	0	0
Derivatives	0	0
Accrued interest receivable	0	0
Noninterest-bearing deposits	1,712,875	1,617,049
Interest-bearing deposits	3,619,315	3,565,795
Borrowings	0	0
Subordinated debentures	0	0
Accrued interest payable	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and due from banks	0	0
Securities available-for-sale	667,025	525,747
Equity securities	1,940	2,713
Net loans	0	0
Derivatives	31,285	3,347
Accrued interest receivable	2,649	1,554
Noninterest-bearing deposits	0	0
Interest-bearing deposits	1,252,350	1,150,563
Borrowings	872,176	469,671
Subordinated debentures	153,952	163,995
Accrued interest payable	3,120	2,716
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and due from banks	0	0
Securities available-for-sale	8,422	8,565
Equity securities	0	0
Net loans	6,993,635	6,800,287
Derivatives	0	0
Accrued interest receivable	31,966	32,598
Noninterest-bearing deposits	0	0
Interest-bearing deposits	0	0
Borrowings	0	0
Subordinated debentures	0	0
Accrued interest payable	$ 0	$ 0