Note 3 - Loans and Allowance for Loan Losses - Loans by Credit Quality (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Loans receivable	$ 637,375,018	$ 544,398,300
Real Estate, Construction [Member]
Loans receivable	64,743,582	40,912,307
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	261,866,285	249,580,873
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	106,300,790	106,410,559
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	85,225,074	48,483,523
Commercial Portfolio Segment [Member]
Loans receivable	94,522,840	75,404,732
Consumer and Other Loans [Member]
Loans receivable	24,716,447	23,606,306
Pass [Member]
Loans receivable	613,664,000	518,988,000
Pass [Member] | Real Estate, Construction [Member]
Loans receivable	60,291,000	35,465,000
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	254,658,000	242,200,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	96,723,000	100,367,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	84,450,000	48,483,000
Pass [Member] | Commercial Portfolio Segment [Member]
Loans receivable	93,102,000	69,093,000
Pass [Member] | Consumer and Other Loans [Member]
Loans receivable	24,440,000	23,380,000
Special Mention [Member]
Loans receivable	9,577,000	13,016,000
Special Mention [Member] | Real Estate, Construction [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	5,578,000	5,922,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	3,799,000	2,591,000
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	200,000	4,503,000
Special Mention [Member] | Consumer and Other Loans [Member]
Loans receivable	0	0
Substandard [Member]
Loans receivable	13,621,000	11,810,000
Substandard [Member] | Real Estate, Construction [Member]
Loans receivable	4,453,000	5,447,000
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	1,630,000	1,459,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	5,779,000	3,453,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	775,000	0
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans receivable	708,000	1,225,000
Substandard [Member] | Consumer and Other Loans [Member]
Loans receivable	276,000	226,000
Doubtful [Member]
Loans receivable	513,000	584,000
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	513,000	584,000
Doubtful [Member] | Consumer and Other Loans [Member]
Loans receivable	$ 0	$ 0