Statements of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Class A Common Stock	Class B Common Stock
Balances, beginning of period at Dec. 31, 2008	$ 827,544	$ 79,653	$ 633,749	$ 113,697	$ 427	$ 18
Increase (Decrease) in Shareholders' Equity
Stock options and restricted stock issued	893	890			3
Stock based compensation expense	8,623	8,623
Income tax effect of stock option exercises	(98)	(98)
Dividends	(13,664)		(13,664)
Comprehensive earnings:
Net (loss) earnings	54,030		54,030
Effect of derivative instruments, net of income taxes	(174,069)			(174,069)
Total comprehensive (loss) earnings	(120,039)
Balances, end of period at Dec. 31, 2009	703,259	89,068	674,115	(60,372)	430	18
Increase (Decrease) in Shareholders' Equity
Issuance of stock	224,313	224,233			80
Stock options and restricted stock issued	4,402	4,398			4
Stock based compensation expense	9,386	9,386
Income tax effect of stock option exercises	284	284
Dividends	(16,181)		(16,181)
Comprehensive earnings:
Net (loss) earnings	82,524		82,524
Amortization of Accumulated other comprehensive loss related to de-designated hedges, net of taxes	16,566			16,566
Total comprehensive (loss) earnings	99,090
Balances, end of period at Dec. 31, 2010	1,024,553	327,369	740,458	(43,806)	514	18
Increase (Decrease) in Shareholders' Equity
Stock options and restricted stock issued	10,113	10,106			7
Stock based compensation expense	9,636	9,636
Income tax effect of stock option exercises	3,047	3,047
Dividends	(16,846)		(16,846)
Comprehensive earnings:
Net (loss) earnings	(228,063)		(228,063)
Amortization of Accumulated other comprehensive loss related to de-designated hedges, net of taxes	38,289			38,289
Total comprehensive (loss) earnings	(189,774)
Balances, end of period at Dec. 31, 2011	$ 840,729	$ 350,158	$ 495,549	$ (5,517)	$ 521	$ 18