Note 9 - Commitments and Off-balance Sheet Risk - Exposure to Credit Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Contractual amounts of financial instruments with off-balance sheet risk	$ 2,460,472	$ 2,379,305
Standby Letters of Credit [Member]
Contractual amounts of financial instruments with off-balance sheet risk	35,966	26,813
Unused lines of Credit [Member] \| Commercial Portfolio Segment [Member]
Contractual amounts of financial instruments with off-balance sheet risk	1,735,667	1,755,132
Unused lines of Credit [Member] \| One to Four Family Mortgages [Member]
Contractual amounts of financial instruments with off-balance sheet risk	117,858	135,021
Unused lines of Credit [Member] \| Credit Card Lines of Credit [Member]
Contractual amounts of financial instruments with off-balance sheet risk	236,298	204,783
Unused lines of Credit [Member] \| Consumer Other Financing Receivable 1 [Member]
Contractual amounts of financial instruments with off-balance sheet risk	47,016	53,124
Loan Origination Commitments [Member]
Contractual amounts of financial instruments with off-balance sheet risk	$ 287,667	$ 204,432