Note 1 - Significant Accounting Policies - Noninterest Income (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Service Charges on Deposit and Sweep Accounts [Member]
Noninterest revenue	$ 1,579,000	$ 1,324,000	$ 4,489,000	$ 3,687,000
Credit and Debit Card [Member]
Noninterest revenue	2,086,000	1,947,000	6,101,000	5,545,000
Payroll Processing [Member]
Noninterest revenue	533,000	412,000	1,635,000	1,374,000
Customer Service [Member]
Noninterest revenue	$ 210,000	$ 241,000	$ 654,000	$ 650,000