Note 14 - Disclosure of Financial Instruments Not Reported at Fair Value - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Cash and cash equivalents	$ 666,719	$ 886,376
Accrued interest receivable	28,579	28,783
Non-interest bearing	1,456,324	1,435,846
Time deposits	1,743,513	1,736,534
Accrued interest payable	1,706	1,740
Reported Value Measurement [Member]
Cash and cash equivalents	666,719	886,376
HTM debt securities	192,956	198,946
Federal Home Loan Bank stock	20,717	20,717
Loans, net	7,132,833	6,949,443
Accrued interest receivable	28,579	28,783
Mortgage servicing rights	9,776	10,189
Non-interest bearing	1,456,324	1,435,846
Transaction deposits	4,557,399	4,618,757
Time deposits	1,743,513	1,736,534
Securities sold under agreement to repurchase	87,513	112,476
Federal funds purchased	7,345	7,289
Subordinated debentures	26,806	26,806
FHLB advances	300,000	300,000
Accrued interest payable	1,706	1,740
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	666,719	886,376
HTM debt securities	175,255	181,203
Federal Home Loan Bank stock	20,717	20,717
Loans, net	7,052,710	6,872,537
Accrued interest receivable	28,579	28,783
Mortgage servicing rights	23,053	22,237
Non-interest bearing	1,456,324	1,435,846
Transaction deposits	4,557,399	4,618,757
Time deposits	1,743,609	1,740,161
Securities sold under agreement to repurchase	87,513	112,476
Federal funds purchased	7,345	7,289
Subordinated debentures	26,438	26,547
FHLB advances	295,886	297,101
Accrued interest payable	1,706	1,740
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	666,719	886,376
HTM debt securities	1,996	1,982
Federal Home Loan Bank stock	0	0
Loans, net	0	0
Accrued interest receivable	0	0
Mortgage servicing rights	0	0
Non-interest bearing	1,456,324	1,435,846
Transaction deposits	0	0
Time deposits	0	0
Securities sold under agreement to repurchase	0	0
Federal funds purchased	0	0
Subordinated debentures	0	0
FHLB advances	0	0
Accrued interest payable	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0
HTM debt securities	173,259	179,221
Federal Home Loan Bank stock	20,717	20,717
Loans, net	0	0
Accrued interest receivable	28,579	28,783
Mortgage servicing rights	0	0
Non-interest bearing	0	0
Transaction deposits	4,557,399	4,618,757
Time deposits	1,743,609	1,740,161
Securities sold under agreement to repurchase	87,513	112,476
Federal funds purchased	7,345	7,289
Subordinated debentures	26,438	26,547
FHLB advances	295,886	297,101
Accrued interest payable	1,706	1,740
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
HTM debt securities	0	0
Federal Home Loan Bank stock	0	0
Loans, net	7,052,710	6,872,537
Accrued interest receivable	0	0
Mortgage servicing rights	23,053	22,237
Non-interest bearing	0	0
Transaction deposits	0	0
Time deposits	0	0
Securities sold under agreement to repurchase	0	0
Federal funds purchased	0	0
Subordinated debentures	0	0
FHLB advances	0	0
Accrued interest payable	$ 0	$ 0