Note 5 - Loans and Allowance for Loan Losses - Loans by Credit Quality (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Loans receivable	$ 780,816,020	$ 637,375,018
Real Estate, Construction [Member]
Loans receivable	105,974,945	64,743,582
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	300,325,513	261,866,285
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	135,439,026	106,300,790
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	83,204,490	85,225,074
Commercial Portfolio Segment [Member]
Loans receivable	120,292,323	94,522,840
Consumer and Other Loans [Member]
Loans receivable	35,579,723	24,716,447
Pass [Member]
Loans receivable	750,785,000	613,664,000
Pass [Member] | Real Estate, Construction [Member]
Loans receivable	101,580,000	60,291,000
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	285,604,000	254,658,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	127,604,000	96,723,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	83,204,000	84,450,000
Pass [Member] | Commercial Portfolio Segment [Member]
Loans receivable	117,553,000	93,102,000
Pass [Member] | Consumer and Other Loans [Member]
Loans receivable	35,240,000	24,440,000
Special Mention [Member]
Loans receivable	9,056,000	9,577,000
Special Mention [Member] | Real Estate, Construction [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	6,545,000	5,578,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	2,217,000	3,799,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Portfolio Segment [Member]
Loans receivable	294,000	200,000
Special Mention [Member] | Consumer and Other Loans [Member]
Loans receivable	0	0
Substandard [Member]
Loans receivable	20,975,000	13,621,000
Substandard [Member] | Real Estate, Construction [Member]
Loans receivable	4,395,000	4,453,000
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	8,177,000	1,630,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	5,618,000	5,779,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable		775,000
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans receivable	2,445,000	708,000
Substandard [Member] | Consumer and Other Loans [Member]
Loans receivable	340,000	276,000
Doubtful [Member]
Loans receivable	0	513,000
Doubtful [Member] | Real Estate, Construction [Member]
Loans receivable	0	0
Doubtful [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	0	0
Doubtful [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	0	0
Doubtful [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	0	0
Doubtful [Member] | Commercial Portfolio Segment [Member]
Loans receivable	0	513,000
Doubtful [Member] | Consumer and Other Loans [Member]
Loans receivable	$ 0	$ 0