Note 4 - Loans Receivable - Internal Classification of the Loan Portfolio (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Loans receivable	$ 754,725	$ 618,031	$ 597,721
Residential Portfolio Segment [Member]
Loans receivable	143,067	144,107	144,972
Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member]
Loans receivable	110,291	116,939
Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member]
Loans receivable	32,776	27,168
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	416,157	328,438	303,660
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Loans receivable	317,829	256,784
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable	51,647	41,739
Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member]
Loans receivable	46,681	29,915
Home Equity Portfolio Segment [Member]
Loans receivable	56,537	52,159	53,342
Consumer Portfolio Segment [Member]
Loans receivable	19,012	16,565	16,491
Commercial Portfolio Segment [Member]
Loans receivable	119,952	76,762	$ 79,256
Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Loans receivable	73,059	59,053
Commercial Portfolio Segment [Member] | Agricultural Loan [Member]
Loans receivable	46,893	17,709
Pass [Member]
Loans receivable	746,114	610,115
Pass [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member]
Loans receivable	109,268	116,065
Pass [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member]
Loans receivable	32,439	26,533
Pass [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Loans receivable	313,594	252,731
Pass [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable	51,647	41,726
Pass [Member] | Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member]
Loans receivable	46,342	29,915
Pass [Member] | Home Equity Portfolio Segment [Member]
Loans receivable	56,438	51,668
Pass [Member] | Consumer Portfolio Segment [Member]
Loans receivable	18,832	16,394
Pass [Member] | Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Loans receivable	71,848	57,778
Pass [Member] | Commercial Portfolio Segment [Member] | Agricultural Loan [Member]
Loans receivable	45,706	17,305
Special Mention [Member]
Loans receivable	2,272	2,681
Special Mention [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member]
Loans receivable	0	0
Special Mention [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Loans receivable	1,647	1,731
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member]
Loans receivable	109	0
Special Mention [Member] | Home Equity Portfolio Segment [Member]
Loans receivable	0	0
Special Mention [Member] | Consumer Portfolio Segment [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Loans receivable	378	950
Special Mention [Member] | Commercial Portfolio Segment [Member] | Agricultural Loan [Member]
Loans receivable	138	0
Substandard [Member]
Loans receivable	5,564	5,154
Substandard [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member]
Loans receivable	1,023	874
Substandard [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member]
Loans receivable	337	635
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Loans receivable	2,413	2,322
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable	0	13
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member]
Loans receivable	172	0
Substandard [Member] | Home Equity Portfolio Segment [Member]
Loans receivable	99	491
Substandard [Member] | Consumer Portfolio Segment [Member]
Loans receivable	180	171
Substandard [Member] | Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Loans receivable	770	244
Substandard [Member] | Commercial Portfolio Segment [Member] | Agricultural Loan [Member]
Loans receivable	570	404
Doubtful [Member]
Loans receivable	775	81
Doubtful [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member]
Loans receivable	0	0
Doubtful [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member]
Loans receivable	0	0
Doubtful [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Loans receivable	175	0
Doubtful [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable	0	0
Doubtful [Member] | Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member]
Loans receivable	58	0
Doubtful [Member] | Home Equity Portfolio Segment [Member]
Loans receivable	0	0
Doubtful [Member] | Consumer Portfolio Segment [Member]
Loans receivable	0	0
Doubtful [Member] | Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Loans receivable	63	81
Doubtful [Member] | Commercial Portfolio Segment [Member] | Agricultural Loan [Member]
Loans receivable	479	0
Unlikely to be Collected Financing Receivable [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Loans [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Residential Portfolio Segment [Member] | One-to-Four Family Construction [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Farmland Loan [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Home Equity Portfolio Segment [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Loans receivable	0	0
Unlikely to be Collected Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Agricultural Loan [Member]
Loans receivable	$ 0	$ 0