Note 4 - Loans and Allowance for Loan Losses - Loans by Aging (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Loans receivable, past due	$ 10,554,000	$ 5,769,000
Loans receivable, current	776,341,000	631,606,000
Loans receivable	786,894,894	637,375,018
Loans receivable, past due and accruing
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	2,670,000	3,736,000
Loans receivable, current	129,741,000	102,565,000
Loans receivable	132,410,810	106,300,790
Loans receivable, past due and accruing
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due	5,952,000	775,000
Loans receivable, current	84,596,000	84,450,000
Loans receivable	90,548,265	85,225,074
Loans receivable, past due and accruing
Real Estate, Construction [Member]
Loans receivable, past due
Loans receivable, current	88,554,000	64,744,000
Loans receivable	88,553,995	64,743,582
Loans receivable, past due and accruing
Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	1,081,000	378,000
Loans receivable, current	321,840,000	261,488,000
Loans receivable	322,921,323	261,866,285
Loans receivable, past due and accruing
Commercial Portfolio Segment [Member]
Loans receivable, past due	732,000	864,000
Loans receivable, current	118,638,000	93,659,000
Loans receivable	119,369,484	94,522,840
Loans receivable, past due and accruing
Consumer and Other Loans [Member]
Loans receivable, past due	119,000	16,000
Loans receivable, current	32,972,000	24,700,000
Loans receivable	33,091,017	24,716,447
Loans receivable, past due and accruing
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, past due	7,464,000	1,812,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	177,000	510,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due	5,952,000	775,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	1,000,000	243,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	228,000	276,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	107,000	8,000
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, past due	855,000	874,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	329,000	731,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	81,000	135,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	433,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	12,000	8,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, past due	2,235,000	3,083,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	2,164,000	2,495,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	71,000	588,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due