Consolidated Statements Of Stockholders' Equity (USD $)	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Total
Balance at Dec. 31, 2011	$ 1	$ 99,003,018	$ 7,509,165	$ 106,512,184
Balance, shares at Dec. 31, 2011	2,107,681
Net income attributable to the Company		1,432,139		1,432,139
Dividends		(147,097)		(147,097)
Shares of common stock repurchased and retired		(509,711)		(509,711)
Shares of common stock repurchased and retired, shares	(12,317)
Stock options exercised		45,062		45,062
Stock options exercised, shares	2,200
Share-based compensation expense		17,690		17,690
Amortization related to postretirement health benefits			1,662	1,662
Net unrealized gain on investments			1,177,658	1,177,658
Balance at Mar. 31, 2012	1	99,841,101	8,688,485	108,529,587
Balance, shares at Mar. 31, 2012	2,097,564
Balance at Dec. 31, 2012	1	105,820,459	8,818,430	114,638,890
Balance, shares at Dec. 31, 2012	2,043,359
Net income attributable to the Company		3,376,730		3,376,730
Dividends		(163,677)		(163,677)
Shares of common stock repurchased and retired		(114,958)		(114,958)
Shares of common stock repurchased and retired, shares	(1,791)
Stock options exercised		166,585		166,585
Stock options exercised, shares	4,400			1,400
Share-based compensation expense		17,737		17,737
Amortization related to postretirement health benefits			788	788
Net unrealized gain on investments			1,558,762	1,558,762
Other		22,438		22,438
Balance at Mar. 31, 2013	$ 1	$ 109,125,314	$ 10,377,980	$ 119,503,295
Balance, shares at Mar. 31, 2013	2,045,968