Comprehensive Income (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Comprehensive Income
Net income	$ 151,832	$ 131,785	$ 430,159	$ 356,861
Other comprehensive income:
Foreign currency translation			(37,547)	13,526
Pension and other post-retirement benefit adjustments:
Recognition of prior service credit, net of tax			(3,931)	(3,755)
Recognition of actuarial loss, net of tax			14,438	16,799
Net actuarial gain, net of tax				14,825
Total other comprehensive income			(27,040)	41,395
Comprehensive income	84,900	171,800	403,119	398,256
Comprehensive Income (Textual) [Abstract]
Comprehensive income	$ 84,900	$ 171,800	$ 403,119	$ 398,256

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The adjustment out of other comprehensive income for prior service costs recognized as a component of net period benefit cost during the period, after tax.

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