Note 9 - Commitments and Off-balance-sheet Risk - Exposure to Credit Losses (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Contractual amounts of financial instruments with off-balance sheet risk	$ 2,265,964	$ 2,379,305
Standby Letters of Credit [Member]
Contractual amounts of financial instruments with off-balance sheet risk	34,116	26,813
Unused lines of Credit [Member] \| Commercial Portfolio Segment [Member]
Contractual amounts of financial instruments with off-balance sheet risk	1,625,477	1,755,132
Unused lines of Credit [Member] \| One to Four Family Mortgages [Member]
Contractual amounts of financial instruments with off-balance sheet risk	110,918	135,021
Unused lines of Credit [Member] \| Credit Card Lines of Credit [Member]
Contractual amounts of financial instruments with off-balance sheet risk	212,045	204,783
Unused lines of Credit [Member] \| Consumer Other Financing Receivable 1 [Member]
Contractual amounts of financial instruments with off-balance sheet risk	49,508	53,124
Loan Origination Commitments [Member]
Contractual amounts of financial instruments with off-balance sheet risk	$ 233,900	$ 204,432