Note 6 - Securities Sold Under Agreements to Repurchase - Securities Sold Under Agreement to Repurchase (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Securities sold under agreements to repurchase	$ 203,339,000	$ 197,463,000
Average daily balance during the period	196,327,000	158,855,000
Maximum daily balance during the period	$ 224,345,000	$ 209,093,000
Securities Sold under Agreements to Repurchase [Member]
Average interest rate at end of period	0.10%	0.11%
Average interest rate during the period	0.10%	0.11%