Note 4 - Loans - Delinquencies Within the Loan Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Past due	$ 6,409	$ 3,509
Non-accrual Loans	3,641	2,290
Current Loans	770,488	612,232
Loans receivable	780,538	618,031
Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	4,600	2,032
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	1,809	1,477
Residential Portfolio Segment [Member]
Loans receivable	157,898	144,107
Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member]
Past due	706	511
Non-accrual Loans	618	253
Current Loans	117,972	116,175
Loans receivable	119,296	116,939
Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	702	381
Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	4	130
Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member]
Past due	260	118
Non-accrual Loans	337	634
Current Loans	38,005	26,416
Loans receivable	38,602	27,168
Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	260	118
Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	434,025	328,438
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Past due	793	2,322
Non-accrual Loans	583	432
Current Loans	329,686	254,030
Loans receivable	331,062	256,784
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	793	975
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	1,347
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Past due	72	9
Non-accrual Loans	50	13
Current Loans	52,548	41,717
Loans receivable	52,670	41,739
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	72	9
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member]
Past due	1,039	0
Non-accrual Loans	476	0
Current Loans	48,778	29,915
Loans receivable	50,293	29,915
Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	1,039	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Home Equity Portfolio Segment [Member]
Past due	420	39
Non-accrual Loans	98	491
Current Loans	55,896	51,629
Loans receivable	56,414	52,159
Home Equity Portfolio Segment [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	420	39
Home Equity Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Consumer Portfolio Segment [Member]
Past due	128	135
Non-accrual Loans	156	127
Current Loans	18,598	16,303
Loans receivable	18,882	16,565
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	128	135
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Portfolio Segment [Member]
Loans receivable	113,319	76,762
Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Past due	484	284
Non-accrual Loans	824	308
Current Loans	71,489	58,461
Loans receivable	72,797	59,053
Commercial Portfolio Segment [Member] | Commercial Loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	484	284
Commercial Portfolio Segment [Member] | Commercial Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Portfolio Segment [Member] | Agricultural Loan [Member]
Past due	2,507	91
Non-accrual Loans	499	32
Current Loans	37,516	17,586
Loans receivable	40,522	17,709
Commercial Portfolio Segment [Member] | Agricultural Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	702	91
Commercial Portfolio Segment [Member] | Agricultural Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	$ 1,805	$ 0