Shareholders' Equity (Details) (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent			$ 1,251,582	$ 1,146,206	$ 1,146,206
Net Income	56,454	38,558	114,865	95,511	217,586
Dividends			(88,504)		(164,514)
Issuance of shares under incentive stock plans			7,894		26,314
Stock-based compensation			8,021		15,223
Excess tax benefit on stock-based compensation			4,900		5,411
Repurchase of common shares			(7,828)		(6,028)
Amortization of pension and postretirement plans	2,094	535	4,188	4,639	6,385
Foreign currency translation adjustment	7,442	(2,045)	7,729	(3,261)	4,162
Joint venture cash flow hedges	699	816	132	1,026	837
Stockholders' Equity Attributable to Parent	1,302,979		1,302,979		1,251,582
Common Stock, Dividends, Per Share, Declared	$ 0.54	$ 0.50	$ 1.08	$ 1.00	$ 2.04
Common Stock Including Additional Paid in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent			602,882	561,962	561,962
Shares, Issued			80,682,093	79,541,974	79,541,974
Issuance of shares under incentive stock plans			7,894		26,314
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			662,671		1,276,227
Stock-based compensation			8,021		15,223
Excess tax benefit on stock-based compensation			4,900		5,411
Repurchase of common shares			(7,828)		(6,028)
Stock Repurchased During Period, Shares			(139,129)		(136,108)
Stockholders' Equity Attributable to Parent	615,869		615,869		602,882
Shares, Issued	81,205,635		81,205,635		80,682,093
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent			717,058	663,986	663,986
Net Income			114,865		217,586
Dividends			(88,504)		(164,514)
Stockholders' Equity Attributable to Parent	743,419		743,419		717,058
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent			(68,358)	(79,742)	(79,742)
Amortization of pension and postretirement plans			4,188		6,385
Foreign currency translation adjustment			7,729		4,162
Joint venture cash flow hedges			132		837
Stockholders' Equity Attributable to Parent	$ (56,309)		$ (56,309)		$ (68,358)