CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($)	ADDITIONAL PAID IN CAPITAL [Member]	RETAINED EARNINGS [Member]	TREASURY STOCK [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) [Member]	Total
Beginning Balance at Dec. 31, 2014	$ 28,779,108	$ 8,640,291	$ (1,902,439)	$ 1,243,022	$ 36,759,982
Net income		4,884,288			4,884,288
Other comprehensive income				(250,473)	(250,473)
Exercise of stock options	122,946				122,946
10% stock dividend	7,360,703	(7,020,505)	(344,976)		(4,778)
Stock-based compensation expense	78,987				78,987
Cash dividends		(2,439,240)			(2,439,240)
Ending balance at Dec. 31, 2015	36,341,744	4,064,834	(2,247,415)	992,549	39,151,712
Net income		5,247,063			5,247,063
Other comprehensive income				(1,599,658)	(1,599,658)
Exercise of stock options	405,749				405,749
Stock-based compensation expense	76,529				76,529
Cash dividends		(2,668,421)			(2,668,421)
Ending balance at Dec. 31, 2016	36,824,022	6,643,476	(2,247,415)	(607,109)	40,612,974
Net income		4,901,825			4,901,825
Other comprehensive income				(276,879)	(276,879)
Exercise of stock options	340,843				340,843
Stock-based compensation expense	71,701				71,701
Reclassification of tax effects stranded in accumulated other comprehensive income by tax reform		(187,692)		187,692
Cash dividends		(2,885,829)			(2,885,829)
Ending balance at Dec. 31, 2017	$ 37,236,566	$ 8,471,780	$ (2,247,415)	$ (696,296)	$ 42,764,635