Note 7 - Loans Receivable and Credit Disclosures - Amortized Cost Basis of Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Collateral dependent loans	$ 11,340		$ 14,386
Collateral dependent loans, ACL	16,319	$ 16,269	15,697	$ 16,420	$ 16,484	$ 16,621
Construction Real Estate [Member]
Collateral dependent loans	0		0
Collateral dependent loans, ACL	412	391	730	606	645	675
Family Residential Real Estate 1-4 [Member]
Collateral dependent loans	803		805
Collateral dependent loans, ACL	3,357	3,288	3,028	2,920	2,899	2,752
Multifamily [Member]
Collateral dependent loans	0		0
Collateral dependent loans, ACL	2,524	2,568	2,493	2,517	2,433	2,501
Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans	9,022		12,853
Collateral dependent loans, ACL	5,033	5,206	4,742	5,843	5,881	5,905
Agriculture Real Estate [Member]
Collateral dependent loans	486		165
Collateral dependent loans, ACL	1,214	1,218	1,625	1,692	1,630	1,584
Commercial Portfolio Segment [Member]
Collateral dependent loans	278		200
Collateral dependent loans, ACL	2,014	1,784	1,153	1,125	1,152	1,170
Agriculture [Member]
Collateral dependent loans	736		342
Collateral dependent loans, ACL	1,358	1,392	1,705	1,484	1,606	1,836
Consumer and Other [Member]
Collateral dependent loans	15		21
Collateral dependent loans, ACL	407	$ 422	$ 221	$ 233	$ 238	$ 198
Real Estate [Member]
Collateral dependent loans	10,687
Real Estate [Member] \| Construction Real Estate [Member]
Collateral dependent loans	0
Real Estate [Member] \| Family Residential Real Estate 1-4 [Member]
Collateral dependent loans	803
Real Estate [Member] \| Multifamily [Member]
Collateral dependent loans	0
Real Estate [Member] \| Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans	9,022
Real Estate [Member] \| Agriculture Real Estate [Member]
Collateral dependent loans	486
Real Estate [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans	124
Real Estate [Member] \| Agriculture [Member]
Collateral dependent loans	252
Real Estate [Member] \| Consumer and Other [Member]
Collateral dependent loans	0
Equipment [Member]
Collateral dependent loans	43
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	40
Equipment [Member] \| Consumer and Other [Member]
Collateral dependent loans	0
Other [Member]
Collateral dependent loans	541
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	97
Other [Member] \| Agriculture [Member]
Collateral dependent loans	444
Collateral Pledged [Member]
Collateral dependent loans	11,271
Collateral dependent loans, ACL	177
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	803
Collateral dependent loans, ACL	10
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	9,022
Collateral dependent loans, ACL	0
Collateral Pledged [Member] \| Agriculture Real Estate [Member]
Collateral dependent loans	486
Collateral dependent loans, ACL	0
Collateral Pledged [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans	224
Collateral dependent loans, ACL	97
Collateral Pledged [Member] \| Agriculture [Member]
Collateral dependent loans	736
Collateral dependent loans, ACL	70
Collateral Pledged [Member] \| Consumer and Other [Member]
Collateral dependent loans	0
Collateral dependent loans, ACL	$ 0