Note 7 - Loans Receivable and Credit Disclosures - Amortized Cost Basis of Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Collateral dependent loans	$ 11,443	$ 14,386
Collateral dependent loans, ACL	16,269	15,697	$ 16,484	$ 16,621
Construction Real Estate [Member]
Collateral dependent loans	0	0
Collateral dependent loans, ACL	391	730	645	675
Family Residential Real Estate 1-4 [Member]
Collateral dependent loans	817	805
Collateral dependent loans, ACL	3,288	3,028	2,899	2,752
Multifamily [Member]
Collateral dependent loans	0	0
Collateral dependent loans, ACL	2,568	2,493	2,433	2,501
Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans	9,176	12,853
Collateral dependent loans, ACL	5,206	4,742	5,881	5,905
Agriculture Real Estate [Member]
Collateral dependent loans	494	165
Collateral dependent loans, ACL	1,218	1,625	1,630	1,584
Commercial Portfolio Segment [Member]
Collateral dependent loans	188	200
Collateral dependent loans, ACL	1,784	1,153	1,152	1,170
Agriculture [Member]
Collateral dependent loans	752	342
Collateral dependent loans, ACL	1,392	1,705	1,606	1,836
Consumer and Other [Member]
Collateral dependent loans	16	21
Collateral dependent loans, ACL	422	$ 221	$ 238	$ 198
Real Estate [Member]
Collateral dependent loans	10,875
Real Estate [Member] \| Construction Real Estate [Member]
Collateral dependent loans	0
Real Estate [Member] \| Family Residential Real Estate 1-4 [Member]
Collateral dependent loans	817
Real Estate [Member] \| Multifamily [Member]
Collateral dependent loans	0
Real Estate [Member] \| Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans	9,176
Real Estate [Member] \| Agriculture Real Estate [Member]
Collateral dependent loans	494
Real Estate [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans	128
Real Estate [Member] \| Agriculture [Member]
Collateral dependent loans	260
Real Estate [Member] \| Consumer and Other [Member]
Collateral dependent loans	0
Equipment [Member]
Collateral dependent loans	45
Equipment [Member] \| Construction Real Estate [Member]
Collateral dependent loans	0
Equipment [Member] \| Family Residential Real Estate 1-4 [Member]
Collateral dependent loans	0
Equipment [Member] \| Multifamily [Member]
Collateral dependent loans	0
Equipment [Member] \| Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans	0
Equipment [Member] \| Agriculture Real Estate [Member]
Collateral dependent loans	0
Equipment [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans	3
Equipment [Member] \| Agriculture [Member]
Collateral dependent loans	42
Equipment [Member] \| Consumer and Other [Member]
Collateral dependent loans	0
Other [Member]
Collateral dependent loans	450
Other [Member] \| Construction Real Estate [Member]
Collateral dependent loans	0
Other [Member] \| Family Residential Real Estate 1-4 [Member]
Collateral dependent loans	0
Other [Member] \| Multifamily [Member]
Collateral dependent loans	0
Other [Member] \| Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans	0
Other [Member] \| Agriculture Real Estate [Member]
Collateral dependent loans	0
Other [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans	0
Other [Member] \| Agriculture [Member]
Collateral dependent loans	450
Collateral Pledged [Member]
Collateral dependent loans	11,370
Collateral dependent loans, ACL	103
Collateral Pledged [Member] \| Construction Real Estate [Member]
Collateral dependent loans	0
Collateral dependent loans, ACL	0
Collateral Pledged [Member] \| Family Residential Real Estate 1-4 [Member]
Collateral dependent loans	817
Collateral dependent loans, ACL	22
Collateral Pledged [Member] \| Multifamily [Member]
Collateral dependent loans	0
Collateral dependent loans, ACL	0
Collateral Pledged [Member] \| Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans	9,176
Collateral dependent loans, ACL	0
Collateral Pledged [Member] \| Agriculture Real Estate [Member]
Collateral dependent loans	494
Collateral dependent loans, ACL	0
Collateral Pledged [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans	131
Collateral dependent loans, ACL	0
Collateral Pledged [Member] \| Agriculture [Member]
Collateral dependent loans	752
Collateral dependent loans, ACL	81
Collateral Pledged [Member] \| Consumer and Other [Member]
Collateral dependent loans	0
Collateral dependent loans, ACL	$ 0