Shareholders' Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended	0 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Apr. 02, 2013 Warrants on Senior Exchangeable Notes due 2012 [Member]	Mar. 31, 2013 Warrants on Senior Exchangeable Notes due 2012 [Member]	Mar. 31, 2013 Common Stock Including Additional Paid in Capital [Member]	Dec. 31, 2012 Common Stock Including Additional Paid in Capital [Member]	Mar. 31, 2013 Common Stock Including Additional Paid in Capital [Member] Warrants on Senior Exchangeable Notes due 2012 [Member]	Mar. 31, 2013 Retained Earnings [Member]	Dec. 31, 2012 Retained Earnings [Member]	Mar. 31, 2013 Accumulated Other Comprehensive Income (Loss) [Member]	Dec. 31, 2012 Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent, Period Start	$ 1,438,004	$ 1,323,073	$ 1,323,073			$ 670,749	$ 630,286		$ 876,634	$ 806,235	$ (109,379)	$ (113,448)
Shares Issued, Period Start						123,332,444	122,035,177
Net Income	147,735	53,437	278,685						147,735	278,685
Dividends	(55,396)		(208,286)						(55,396)	(208,286)
Issuance of shares under incentive stock plans	4,091		25,495			4,091	25,495
Issuance of shares under incentive stock plan, Shares						743,381	1,467,024
Stock-based compensation	3,308		15,116			3,308	15,116
Excess tax benefit on stock-based compensation	6,191		7,635			6,191	7,635
Repurchase of common shares	(11,241)		(7,783)			(11,241)	(7,783)
Stock Repurchased During Period, Shares						(209,743)	(169,757)
Maturity of Warrants, Value	0							0
Maturity of Warrants, Shares				97,918	2,036,976			2,036,976
Net gain (loss) from pension and postretirement plans	4,969	3,140	(496)								4,969	(496)
Foreign currency translation adjustment	975	5,825	4,352								975	4,352
Joint venture cash flow hedges	554	1,205	213								554	213
Stockholders' Equity Attributable to Parent, Period End	$ 1,539,190		$ 1,438,004			$ 673,098	$ 670,749		$ 968,973	$ 876,634	$ (102,881)	$ (109,379)
Shares Issued, Period End						125,903,058	123,332,444
Dividends [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 0.44	$ 0.40	$ 1.68