Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance at Dec. 31, 2017	$ 687,850	$ 50,856,069	$ (37,125,541)	$ 60,679,308	$ (206,193)	$ 74,891,493
Net income				1,355,745		1,355,745
Other comprehensive income (loss)					(26,942)	(26,942)
Dividends on common stock				(532,771)		(532,771)
Stock award plans		(35,357)	158,592			123,235
Stock options exercised	450	23,330				23,780
Balance at Mar. 31, 2018	688,300	50,844,042	(36,966,949)	61,502,282	(233,135)	75,834,540
Net income				(342,984)		(342,984)
Other comprehensive income (loss)					91,016	91,016
Dividends on common stock				(534,272)		(534,272)
Stock award plans		161,235				161,235
Stock options exercised	750	37,900				38,650
Balance at Jun. 30, 2018	689,050	51,043,177	(36,966,949)	60,625,026	(142,119)	75,248,185
Net income				3,934,242		3,934,242
Other comprehensive income (loss)					(249,491)	(249,491)
Dividends on common stock				(534,207)		(534,207)
Stock award plans		154,137	(8,079)			146,058
Stock options exercised	500	69,400				69,900
Balance at Sep. 30, 2018	689,550	51,266,714	(36,975,028)	64,025,061	(391,610)	78,614,687
Net income				2,384,876		2,384,876
Other comprehensive income (loss)					(61,146)	(61,146)
Dividends on common stock				(580,250)		(580,250)
Stock award plans		82,621	3,904			86,525
Stock options exercised	650	33,250				33,900
Balance at Dec. 31, 2018	690,200	51,382,585	(36,971,124)	65,829,687	(452,756)	80,478,592
Net income				2,120,364		2,120,364
Other comprehensive income (loss)					380,791	380,791
Dividends on common stock				(582,817)		(582,817)
Stock award plans		(53,689)	222,789			169,100
Stock options exercised	1,000	50,900				51,900
Balance at Mar. 31, 2019	$ 691,200	$ 51,379,796	$ (36,748,335)	$ 67,367,234	$ (71,965)	$ 82,617,930