Consolidated Statements Of Stockholders' Equity (USD $)	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income
Balance, beginning of year at Dec. 31, 2013	$ 128,062,154	$ 1	$ 116,714,749	$ 11,347,404
Balance, beginning of year, shares at Dec. 31, 2013		2,037,135
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	986,438		986,438
Dividends	(162,946)		(162,946)
Shares of common stock repurchased and retired (in shares)		(500)
Shares of common stock repurchased and retired	(39,825)		(39,825)
Stock options and stock appreciation rights exercised (in shares)		196
Stock options and stock appreciation rights exercised	(19)		(19)
Share-based compensation expense	21,572		21,572
Amortization related to postretirement health benefits	366			366
Net unrealized gain on investments	3,101			3,101
Income tax benefit from share-based compensation	2,889		2,889
Balance, end of year at Mar. 31, 2014	128,873,730	1	117,522,858	11,350,871
Balance, end of year, shares at Mar. 31, 2014		2,036,831
Balance, beginning of year at Dec. 31, 2014	137,563,706	1	124,707,196	12,856,509
Balance, beginning of year, shares at Dec. 31, 2014		2,023,270
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	1,726,124		1,726,124
Dividends	(160,957)		(160,957)
Shares of common stock repurchased and retired (in shares)		(15,036)
Shares of common stock repurchased and retired	(1,069,185)		(1,069,185)
Stock options and stock appreciation rights exercised (in shares)		2,192
Stock options and stock appreciation rights exercised	54,988		54,988
Share-based compensation expense	32,600		32,600
Amortization related to postretirement health benefits	1,304			1,304
Net unrealized gain on investments	178,433			178,433
Income tax benefit from share-based compensation	26,875		26,875
Balance, end of year at Mar. 31, 2015	$ 138,353,888	$ 1	$ 125,317,641	$ 13,036,246
Balance, end of year, shares at Mar. 31, 2015		2,010,426