Note 8 - Commitments and Off-balance Sheet Risk - Exposure to Credit Losses (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Contractual amounts of financial instruments with off-balance sheet risk	$ 1,540,413,000	$ 1,565,871,000
Standby Letters of Credit [Member]
Contractual amounts of financial instruments with off-balance sheet risk	32,954,000	33,109,000
Unused lines of Credit [Member] | Commercial Portfolio Segment [Member]
Contractual amounts of financial instruments with off-balance sheet risk	1,115,888,000	1,098,951,000
Unused lines of Credit [Member] | One to Four Family Mortgages [Member]
Contractual amounts of financial instruments with off-balance sheet risk	65,112,000	64,313,000
Unused lines of Credit [Member] | Consumer Credit Card [Member]
Contractual amounts of financial instruments with off-balance sheet risk	95,813,000	92,146,000
Unused lines of Credit [Member] | Consumer Other Financing Receivable 1 [Member]
Contractual amounts of financial instruments with off-balance sheet risk	72,544,000	64,876,000
Loan Origination Commitments [Member]
Contractual amounts of financial instruments with off-balance sheet risk	$ 158,102,000	$ 212,476,000