Consolidated Statements Of Stockholders' Equity (USD $)	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Total
Balance at Dec. 31, 2010	$ 1	$ 98,240,109	$ 5,688,705	$ 103,928,815
Balance, shares at Dec. 31, 2010	2,282,596
Net income		2,614,012		2,614,012
Dividends ($0.14 per share)		(302,221)		(302,221)
Shares of common stock repurchased and retired		(5,210,866)		(5,210,866)
Shares of common stock repurchased and retired, shares	(162,411)
Stock options exercised		152,526		152,526
Stock options exercised, shares	7,550
Share-based compensation expense		106,053		106,053
Amortization related to postretirement health benefits			7,575	7,575
Net unrealized gain on investments			1,082,268	1,082,268
Balance at Jun. 30, 2011	1	95,599,613	6,778,548	102,378,162
Balance, shares at Jun. 30, 2011	2,127,735
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		4,781,627		4,781,627
Dividends ($0.14 per share)		(294,048)		(294,048)
Shares of common stock repurchased and retired		(626,885)		(626,885)
Shares of common stock repurchased and retired, shares	(14,502)
Stock options exercised		152,792		152,792
Stock options exercised, shares	6,130			6,130
Share-based compensation expense		36,947		36,947
Amortization related to postretirement health benefits			3,325	3,325
Net unrealized gain on investments			835,326	835,326
Balance at Jun. 30, 2012	$ 1	$ 103,053,451	$ 8,347,816	$ 111,401,268
Balance, shares at Jun. 30, 2012	2,099,309