Consolidated Statements Of Stockholders' Equity - USD ($)	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interest [Member]
Balance, beginning of year at Dec. 31, 2015	$ 142,777,080	$ 1	$ 131,186,866	$ 11,483,015	$ 107,198
Balance, beginning of year, shares at Dec. 31, 2015		1,949,797
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	1,814,040		1,814,040
Dividends	(309,104)		(309,104)
Shares of common stock repurchased and retired (in shares)		(18,795)
Shares of common stock repurchased and retired	(1,626,668)		(1,626,668)
Stock options and stock appreciation rights exercised (in shares)		1,289
Stock options and stock appreciation rights exercised	(200)		(200)
Share-based compensation expense	35,053		35,053
Amortization related to postretirement health benefits	1,475			1,475
Net unrealized gain on investments	699,846			699,846
Net loss attributable to noncontrolling interests	(9,579)				(9,579)
Income tax benefit from share-based compensation	32,292		32,292
Balance, end of year at Mar. 31, 2016	143,414,235	$ 1	131,132,279	12,184,336	97,619
Balance, end of year, shares at Mar. 31, 2016		1,932,291
Balance, beginning of year at Dec. 31, 2016	155,135,954	$ 1	143,283,621	11,761,447	90,885
Balance, beginning of year, shares at Dec. 31, 2016		1,884,283
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	4,476,055		4,476,055
Dividends	(377,218)		(377,218)
Shares of common stock repurchased and retired (in shares)		(70)
Shares of common stock repurchased and retired	(8,986)		(8,986)
Stock options and stock appreciation rights exercised (in shares)		1,875
Stock options and stock appreciation rights exercised	(380)		(380)
Share-based compensation expense	32,348		32,348
Amortization related to postretirement health benefits	1,422			1,422
Net unrealized gain on investments	1,038,250			1,038,250
Net loss attributable to noncontrolling interests	(9,875)				(9,875)
Balance, end of year at Mar. 31, 2017	$ 160,287,570	$ 1	$ 147,405,440	$ 12,801,119	$ 81,010
Balance, end of year, shares at Mar. 31, 2017		1,886,088