Note 4 - Loans Receivable and Related Allowance for Loan Losses - Impaired Loans by Class (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Impaired loans with specific allowance, unpaid principal balance	$ 2,124	$ 313	$ 2,124	$ 313	$ 877
Impaired loans with specific allowance, recorded investment	2,124	313	2,124	313	877
Related allowance	191	25	191	25	285
Impaired loans with specific allowance, average recorded investment	2,127	316	1,411	398	494
Impaired loans with specific allowance, interest income recognized in period	23	3	80	12	41
Impaired loans with specific allowance, cash basis interest recognized in period	23	3	57	12	41
Impaired loans with no specific allowance, unpaid principal balance	550	1,451	550	1,451	1,121
Impaired loans with no specific allowance, recorded investment	438	1,339	438	1,339	1,009
Impaired loans with no specific allowance, average recorded investment	476	1,395	1,107	1,465	1,374
Impaired loans with no specific allowance, interest income recognized in period	10	11	33	40	79
Impaired loans with no specific allowance, cash basis interest recognized in period	9	11	33	40	79
Residential Portfolio Segment [Member]
Impaired loans with specific allowance, unpaid principal balance	67	0	67	0	68
Impaired loans with specific allowance, recorded investment	67	0	67	0	68
Related allowance	17	0	17	0	1
Impaired loans with specific allowance, average recorded investment	68	0	68	17	28
Impaired loans with specific allowance, interest income recognized in period	1	0	2	0	3
Impaired loans with specific allowance, cash basis interest recognized in period	1	0	2	0	3
Impaired loans with no specific allowance, unpaid principal balance	315	415	315	415	338
Impaired loans with no specific allowance, recorded investment	203	303	203	303	226
Impaired loans with no specific allowance, average recorded investment	207	308	215	299	284
Impaired loans with no specific allowance, interest income recognized in period	1	2	3	4	3
Impaired loans with no specific allowance, cash basis interest recognized in period	1	2	3	4	3
Home Equity Loans and Lines of Credit [Member]
Impaired loans with specific allowance, unpaid principal balance	0	0	0	0	0
Impaired loans with specific allowance, recorded investment	0	0	0	0	0
Related allowance	0	0	0	0	0
Impaired loans with specific allowance, average recorded investment	0	0	0	0	0
Impaired loans with specific allowance, interest income recognized in period	0	0	0	0	0
Impaired loans with specific allowance, cash basis interest recognized in period	0	0	0	0	0
Impaired loans with no specific allowance, unpaid principal balance	4	4	4	4	4
Impaired loans with no specific allowance, recorded investment	4	4	4	4	4
Impaired loans with no specific allowance, average recorded investment	4	4	4	4	4
Impaired loans with no specific allowance, interest income recognized in period	0	0	0	0	0
Impaired loans with no specific allowance, cash basis interest recognized in period	0	0	0	0	0
Commercial Real Estate Portfolio Segment [Member]
Impaired loans with specific allowance, unpaid principal balance	2,040	309	2,040	309	559
Impaired loans with specific allowance, recorded investment	2,040	309	2,040	309	559
Related allowance	157	21	157	21	88
Impaired loans with specific allowance, average recorded investment	2,050	312	1,275	344	387
Impaired loans with specific allowance, interest income recognized in period	22	3	78	12	30
Impaired loans with specific allowance, cash basis interest recognized in period	22	3	55	12	30
Impaired loans with no specific allowance, unpaid principal balance	153	915	153	915	666
Impaired loans with no specific allowance, recorded investment	153	915	153	915	666
Impaired loans with no specific allowance, average recorded investment	185	964	798	1,070	990
Impaired loans with no specific allowance, interest income recognized in period	7	8	23	32	71
Impaired loans with no specific allowance, cash basis interest recognized in period	7	8	23	32	71
Commercial Portfolio Segment [Member]
Impaired loans with specific allowance, unpaid principal balance	17	4	17	4	250
Impaired loans with specific allowance, recorded investment	17	4	17	4	250
Related allowance	17	4	17	4	196
Impaired loans with specific allowance, average recorded investment	9	4	68	37	79
Impaired loans with specific allowance, interest income recognized in period	0	0	0	0	8
Impaired loans with specific allowance, cash basis interest recognized in period	0	0	0	0	8
Impaired loans with no specific allowance, unpaid principal balance	78	117	78	117	113
Impaired loans with no specific allowance, recorded investment	78	117	78	117	113
Impaired loans with no specific allowance, average recorded investment	80	119	90	92	96
Impaired loans with no specific allowance, interest income recognized in period	2	1	7	4	5
Impaired loans with no specific allowance, cash basis interest recognized in period	1	1	7	4	5
Consumer Portfolio Segment [Member]
Impaired loans with specific allowance, unpaid principal balance	0	0	0	0	0
Impaired loans with specific allowance, recorded investment	0	0	0	0	0
Related allowance	0	0	0	0	0
Impaired loans with specific allowance, average recorded investment	0	0	0	0	0
Impaired loans with specific allowance, interest income recognized in period	0	0	0	0	0
Impaired loans with specific allowance, cash basis interest recognized in period	0	0	0	0	0
Impaired loans with no specific allowance, unpaid principal balance	0	0	0	0	0
Impaired loans with no specific allowance, recorded investment	0	0	0	0	0
Impaired loans with no specific allowance, average recorded investment	0	0	0	0	0
Impaired loans with no specific allowance, interest income recognized in period	0	0	0	0	0
Impaired loans with no specific allowance, cash basis interest recognized in period	$ 0	$ 0	$ 0	$ 0	$ 0