Note 6 - Securities Sold Under Agreements to Repurchase - Securities Sold Under Agreement to Repurchase (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Securities sold under agreements to repurchase	$ 227,453,000	$ 194,340,000
Average daily balance during the period	195,574,000	200,499,000
Maximum daily balance during the period	$ 255,180,000	$ 235,577,000
Securities Sold under Agreements to Repurchase [Member]
Average interest rate at end of period	1.44%	0.75%
Average interest rate during the period	0.84%	0.15%