Note 13 - Federal and State Income Taxes - Reconciliation of the Expected Federal Income Tax Expense (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Computed "expected" tax expense									$ 12,806,351	$ 7,208,993	$ 6,297,027
Computed "expected" tax expense, percentage									35.00%	35.00%	35.00%
Effect of graduated tax rates									$ (250,013)	$ (76,973)	$ (79,529)
Effect of graduated tax rates, percentage									(0.70%)	(0.40%)	(0.40%)
Tax exempt income, net									$ (4,343,270)	$ (3,461,438)	$ (2,646,275)
Tax exempt income, net, percentage									(11.90%)	(16.80%)	(14.70%)
Bank-owned life insurance									$ 619,988	$ 616,737	$ 585,312
Bank-owned life insurance, percentage									(1.70%)	(3.00%)	(3.30%)
State income taxes, net of federal benefit, current year									$ 1,245,524	$ 767,557	$ 497,068
State income taxes, net of federal benefit, current year, percentage									3.40%	3.70%	2.80%
Change in unrecognized tax benefits									$ 121,008	$ 223,668	$ (55,728)
Change in unrecognized tax benefits, percentage									0.30%	1.10%	(0.30%)
Acquisition costs									$ 176,050
Acquisition costs, percentage									0.50%
Other									$ (232,875)	$ (375,828)	$ (388,281)
Other, percentage									(0.60%)	(1.80%)	(2.10%)
	$ 2,872,412	$ 1,858,208	$ 2,153,144	$ 2,019,023	$ 2,263,293	$ 2,468,871	$ (1,974,411)	$ 911,489	$ 8,902,787	$ 3,669,242	$ 3,038,970
Income Tax Expense (Benefit), Pprcentage									24.30%	17.80%	17.00%