Statements of Stockholders' Equity (USD $)	Class A Common Stock	Class C Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock	Total
Balance at Dec. 31, 2012	$ 21,687,152	$ 2,194,820	$ 21,262,140	$ 1,934,359	$ 35,114,072	$ (2,380,434)	$ 79,812,109
Net earnings					2,033,266		2,033,266
Other comprehensive loss				(375,426)			(375,426)
Grant of stock options			52,969				52,969
Exercise of stock options	204,206	86,677	(74,155)				216,728
Sale of treasury stock			63,986			19,727	83,713
Conversion Class C to Class A	1,818	(1,819)	1
Balance at Mar. 31, 2013	21,893,176	2,279,678	21,304,941	1,558,933	37,147,338	(2,360,707)	81,823,359
Balance at Dec. 31, 2013	23,614,574	2,660,382	23,215,875	1,218,396	39,666,587	(2,624,625)	87,751,189
Net earnings					138,848		138,848
Other comprehensive loss				316,135			316,135
Grant of stock options			64,325				64,325
Exercise of stock options	69,910		(19,611)				50,299
Sale of treasury stock			76,478			105,327	181,805
Stock Dividends	3,446	(1)	4,910		(8,355)
Conversion Class C to Class A	1,424	(1,423)	(1)
Balance at Mar. 31, 2014	$ 23,689,354	$ 2,658,958	$ 23,341,976	$ 1,534,531	$ 39,797,080	$ (2,519,298)	$ 88,502,601