Consolidated Statements Of Stockholders' Equity (USD $)	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income
Balance, beginning of year at Dec. 31, 2010	$ 103,928,815	$ 1	$ 98,240,109	$ 5,688,705
Balance, beginning of year, shares at Dec. 31, 2010		2,282,596
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	6,933,936		6,933,936
Dividends	(599,241)		(599,241)
Shares of common stock repurchased and retired (in shares)		(182,615)
Shares of common stock repurchased and retired	(5,940,463)		(5,940,463)
Stock options and stock appreciation rights exercised (in shares)		7,700
Stock options and stock appreciation rights exercised	155,163		155,163
Share-based compensation expense	213,514		213,514
Amortization related to postretirement health benefits	8,394			8,394
Accumulated postretirement benefit obligation adjustment	(75,959)			(75,959)
Net unrealized gain on investments	1,888,025			1,888,025
Balance, end of year at Dec. 31, 2011	106,512,184	1	99,003,018	7,509,165
Balance, end of year, shares at Dec. 31, 2011		2,107,681
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	11,102,496		11,102,496
Dividends	(603,334)		(603,334)
Shares of common stock repurchased and retired (in shares)		(70,702)
Shares of common stock repurchased and retired	(3,975,532)		(3,975,532)
Stock options and stock appreciation rights exercised (in shares)		6,380
Stock options and stock appreciation rights exercised	160,557		160,557
Share-based compensation expense	74,553		74,553
Amortization related to postretirement health benefits	6,648			6,648
Accumulated postretirement benefit obligation adjustment	(54,726)			(54,726)
Net unrealized gain on investments	1,393,943			1,393,943
Other	22,101		58,701	(36,600)
Balance, end of year at Dec. 31, 2012	114,638,890	1	105,820,459	8,818,430
Balance, end of year, shares at Dec. 31, 2012		2,043,359
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	14,708,210		14,708,210
Dividends	(657,914)		(657,914)
Shares of common stock repurchased and retired (in shares)		(56,223)
Shares of common stock repurchased and retired	(4,262,260)		(4,262,260)
Stock options and stock appreciation rights exercised (in shares)		49,999
Stock options and stock appreciation rights exercised	75,797		75,797
Share-based compensation expense	83,852		83,852
Amortization related to postretirement health benefits	3,140			3,140
Accumulated postretirement benefit obligation adjustment	50,961			50,961
Net unrealized gain on investments	2,474,873			2,474,873
Income tax benefit from share-based compensation	946,605		946,605
Balance, end of year at Dec. 31, 2013	$ 128,062,154	$ 1	$ 116,714,749	$ 11,347,404
Balance, end of year, shares at Dec. 31, 2013		2,037,135