CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total		Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2010	$ 362,852,917		$ 12,927,678	$ 88,937,294	$ 24,495,487	$ 236,492,458
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through affiliate's stock plans	974,493		46,113	928,380
Repurchase of common stock	(1,849,896)		(98,200)	(1,751,696)
Increase resulting from stock-based compensation expense associated with affiliate's stock plans allocated to the Company	196,654			196,654
Other comprehensive income	2,845,023				2,845,023
Net income (loss)	(2,737,279)					(2,737,279)
Dividends paid to public stockholders	(3,898,471)					(3,898,471)
Dividends paid to affiliate	(6,042,846)					(6,042,846)
Balance at Dec. 31, 2011	352,340,595		12,875,591	88,310,632	27,340,510	223,813,862
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through affiliate's stock plans	691,552		33,866	657,686
Increase resulting from stock-based compensation expense associated with affiliate's stock plans allocated to the Company	237,563			237,563
Other comprehensive income	20,411,865				20,411,865
Net income (loss)	37,966,429					37,966,429
Dividends paid to public stockholders	(4,082,080)					(4,082,080)
Dividends paid to affiliate	(6,356,760)					(6,356,760)
Balance at Dec. 31, 2012	401,209,164		12,909,457	89,205,881	47,752,375	251,341,451
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through affiliate's stock plans	10,208,452		396,570	9,811,882
Increase resulting from stock-based compensation expense associated with affiliate's stock plans allocated to the Company	290,986			290,986
Other comprehensive income	11,258,114	[1]			11,258,114
Net income (loss)	43,518,673					43,518,673
Dividends paid to public stockholders	(4,526,000)					(4,526,000)
Dividends paid to affiliate	(6,749,153)					(6,749,153)
Balance at Dec. 31, 2013	$ 455,210,236		$ 13,306,027	$ 99,308,749	$ 59,010,489	$ 283,584,971

[1] All amounts are net of tax. Amounts in parentheses indicate debits.