Note 4 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Valuation allowance	$ 1,096	$ 1,612
Loans recorded balance	11,968	20,552
Loans unpaid principal	13,201	21,870
Loans average investment in impaired loans	17,291	16,658
Loans interest income recognized	7	122
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans without a specific valuation allowance, recorded balance	1,392	2
Loans without a specific valuation allowance, unpaid principal	1,392	2
Loans without a specific valuation allowance, average investment in impaired loans	1,075	1,429
Loans without a specific valuation allowance, interest income recognized	1	1
Loans with a specific valuation allowance, recorded balance	1,221	4,518
Loans with a specific valuation allowance, unpaid principal	1,221	4,518
Valuation allowance	197	573
Loans with a specific valuation allowance, average investment in impaired loans	1,781	2,858
Loans with a specific valuation allowance, interest income recognized	0	0
Loans recorded balance	2,613	4,520
Loans unpaid principal	2,613	4,520
Loans average investment in impaired loans	2,856	4,287
Loans interest income recognized	1	1
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans without a specific valuation allowance, recorded balance		5,952
Loans without a specific valuation allowance, unpaid principal		5,952
Loans without a specific valuation allowance, average investment in impaired loans	5,438	2,246
Loans without a specific valuation allowance, interest income recognized		75
Loans with a specific valuation allowance, recorded balance	0	0
Loans with a specific valuation allowance, unpaid principal	0	0
Valuation allowance	0	0
Loans with a specific valuation allowance, average investment in impaired loans		499
Loans with a specific valuation allowance, interest income recognized	0	0
Loans recorded balance		5,952
Loans unpaid principal		5,952
Loans average investment in impaired loans	5,438	2,745
Loans interest income recognized		75
Real Estate, Construction [Member]
Loans without a specific valuation allowance, recorded balance
Loans without a specific valuation allowance, unpaid principal
Loans without a specific valuation allowance, average investment in impaired loans		1,144
Loans without a specific valuation allowance, interest income recognized	0	0
Loans with a specific valuation allowance, recorded balance	4,742	4,088
Loans with a specific valuation allowance, unpaid principal	5,975	5,321
Valuation allowance	553	552
Loans with a specific valuation allowance, average investment in impaired loans	3,924	3,009
Loans with a specific valuation allowance, interest income recognized	0	0
Loans recorded balance	4,742	4,088
Loans unpaid principal	5,975	5,321
Loans average investment in impaired loans	3,924	4,153
Loans interest income recognized	0	0
Commercial Real Estate Portfolio Segment [Member]
Loans without a specific valuation allowance, recorded balance	3,199	3,138
Loans without a specific valuation allowance, unpaid principal	3,199	3,138
Loans without a specific valuation allowance, average investment in impaired loans	3,274	3,764
Loans without a specific valuation allowance, interest income recognized	4	46
Loans with a specific valuation allowance, recorded balance	162	1,232
Loans with a specific valuation allowance, unpaid principal	162	1,317
Valuation allowance	24	106
Loans with a specific valuation allowance, average investment in impaired loans	533	154
Loans with a specific valuation allowance, interest income recognized	0	0
Loans recorded balance	3,361	4,370
Loans unpaid principal	3,361	4,455
Loans average investment in impaired loans	3,807	3,918
Loans interest income recognized	4	46
Commercial Portfolio Segment [Member]
Loans without a specific valuation allowance, recorded balance	33	216
Loans without a specific valuation allowance, unpaid principal	33	216
Loans without a specific valuation allowance, average investment in impaired loans	127	596
Loans without a specific valuation allowance, interest income recognized	0	0
Loans with a specific valuation allowance, recorded balance	999	1,062
Loans with a specific valuation allowance, unpaid principal	999	1,062
Valuation allowance	301	363
Loans with a specific valuation allowance, average investment in impaired loans	756	522
Loans with a specific valuation allowance, interest income recognized	0	0
Loans recorded balance	1,032	1,278
Loans unpaid principal	1,032	1,278
Loans average investment in impaired loans	883	1,118
Loans interest income recognized	0	0
Consumer and Other Loans [Member]
Loans without a specific valuation allowance, recorded balance	70	225
Loans without a specific valuation allowance, unpaid principal	70	225
Loans without a specific valuation allowance, average investment in impaired loans	230	316
Loans without a specific valuation allowance, interest income recognized	2
Loans with a specific valuation allowance, recorded balance	150	119
Loans with a specific valuation allowance, unpaid principal	150	119
Valuation allowance	21	18
Loans with a specific valuation allowance, average investment in impaired loans	153	121
Loans with a specific valuation allowance, interest income recognized	0	0
Loans recorded balance	220	344
Loans unpaid principal	220	344
Loans average investment in impaired loans	383	437
Loans interest income recognized	$ 2