Consolidated Statements of Shareholders' Equity - USD ($)	Total	Common Stock	Capital in Excess of Par	Retained Earnings
Beginning Balance, Value at Dec. 31, 2013	$ 6,910,500	$ 1,144,700	$ 5,615,500	$ 150,300
Beginning Balance, Shares at Dec. 31, 2013	11,446,800	11,446,800
Stock-based compensation, Value	$ 66,700	$ 0	66,700	0
Stock-based compensation, Shares		0
Stock options exercised, Value	41,900	$ 10,300	31,600	0
Stock options exercised, Shares		102,989
Net income	2,093,400	$ 0	0	2,093,400
Ending Balance, Value at Dec. 31, 2014	$ 9,112,500	$ 1,155,000	5,713,800	2,243,700
Ending Balance, Shares at Dec. 31, 2014	11,549,789	11,549,789
Stock-based compensation, Value	$ 162,200	$ 0	162,200	0
Stock-based compensation, Shares		0
Stock options exercised, Value	41,200	$ 16,100	25,100	0
Stock options exercised, Shares		160,956
Net income	4,779,900	$ 0	0	4,779,900
Ending Balance, Value at Dec. 31, 2015	$ 14,095,800	$ 1,171,100	$ 5,901,100	$ 7,023,600
Ending Balance, Shares at Dec. 31, 2015	11,710,745	11,710,745