Note 8 - Disclosures About Fair Value of Assets and Liabilities - Fair Value of Financial Instruments (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Inputs, Level 1 [Member]
Financial assets:
Cash and cash equivalents	$ 10,948,705	$ 18,774,419
Cash and cash equivalents	10,948,705	18,774,419
Fair Value, Inputs, Level 2 [Member]
Financial assets:
Held-to-maturity securities	30,363	43,099
Held-to-maturity securities	31,031	43,935
Federal Home Loan Bank stock	3,767,000	2,837,500
Federal Home Loan Bank stock	3,767,000	2,837,500
Mortgage loans held for sale	2,564,342	1,902,933
Mortgage loans held for sale	2,564,342	1,902,933
Interest receivable	1,808,980	1,986,692
Financial liabilities:
Deposits	515,764,148	517,385,695
Deposits	501,675,796	511,225,380
Federal Home Loan Bank advances	74,600,000	52,100,000
Federal Home Loan Bank advances	74,731,510	53,227,960
Interest payable	203,417	196,102
Fair Value, Inputs, Level 3 [Member]
Financial assets:
Loans, net	525,862,944	491,001,907
Loans, net	528,440,979	495,207,798
Financial liabilities:
Subordinated debentures	15,465,000	15,465,000
Subordinated debentures	15,465,000	15,465,000
Cash and cash equivalents	10,948,705	18,774,419	$ 9,418,464	$ 12,493,890
Held-to-maturity securities	30,363	43,099
Federal Home Loan Bank stock	3,767,000	2,837,500
Mortgage loans held for sale	2,564,342	1,902,933
Loans, net	525,862,944	491,001,907
Interest receivable	1,808,980	1,986,692
Deposits	515,764,148	517,385,695
Subordinated debentures	15,465,000	15,465,000
Interest payable	$ 203,417	$ 196,102