Consolidated Statements Of Stockholders' Equity (USD $)	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income
Balance, beginning of year at Dec. 31, 2011	$ 106,512,184	$ 1	$ 99,003,018	$ 7,509,165
Balance, beginning 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
Temporary Equity, Interest Resulting From Subsidiary Purchase	0
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
Temporary Equity, Interest Resulting From Subsidiary Purchase	0
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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	9,648,975		9,648,975
Dividends	(650,433)		(650,433)
Shares of common stock repurchased and retired (in shares)		(15,372)
Shares of common stock repurchased and retired	(1,055,765)		(1,055,765)
Stock options and stock appreciation rights exercised (in shares)		1,507
Stock options and stock appreciation rights exercised	27,100		27,100
Share-based compensation expense	120,891		120,891
Amortization related to postretirement health benefits	1,465			1,465
Accumulated postretirement benefit obligation adjustment	(31,100)			(31,100)
Net unrealized gain on investments	1,538,740			1,538,740
Temporary Equity, Interest Resulting From Subsidiary Purchase	(114,320)		(114,320)
Income tax benefit from share-based compensation	15,999		15,999
Balance, end of year at Dec. 31, 2014	$ 137,563,706	$ 1	$ 124,707,196	$ 12,856,509
Balance, end of year, shares at Dec. 31, 2014		2,023,270