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, 2011	$ 19,277,596	$ 2,027,195	$ 19,487,565	$ 654,443	$ 22,546,623	$ (2,762,835)	$ 61,230,587
Net earnings					16,712,518		16,712,518
Other comprehensive loss				1,279,916			1,279,916
Grant of stock options			251,031				251,031
Exercise stock options	1,371,506	63,782	(1,416,982)				18,306
Sale of treasury stock			(62,650)			382,401	319,751
Stock dividends	1,037,404	104,488	3,003,177		(4,145,069)
Conversion Class C to Class A	646	(645)	(1)
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					7,585,921		7,585,921
Other comprehensive loss				(715,963)			(715,963)
Grant of stock options			88,369				88,369
Exercise stock options	719,572	422,422	(345,845)			(543,334)	252,815
Sale of treasury stock			428,794			299,143	727,937
Stock dividends	1,124,304	126,685	1,782,418		(3,033,406)		1
Conversion Class C to Class A	83,546	(83,545)	(1)
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					7,754,648		7,754,648
Other comprehensive loss				220,170			220,170
Grant of stock options			391,220				391,220
Reverse stock split true up		30			(30)
Exercise stock options	108,824		(34,800)				74,024
Sale of treasury stock			361,679			538,171	899,850
Stock dividends	1,190,040	132,767	1,997,147		(3,319,954)
Conversion Class C to Class A	5,042	(5,041)	(2)		1
Balance at Dec. 31, 2014	$ 24,918,480	$ 2,788,138	$ 25,931,119	$ 1,438,566	$ 44,101,252	$ (2,086,454)	$ 97,091,101