Benefit Plans and Other Postretirement Benefits (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure
Plan contributions by employer	$ 21,800	$ 22,800	$ 17,300
Expected benefits payments
Contributions to U.S defined contribution plans by the Company, maximum percentage of eligible compensation (as a percent)	5.00%
Matching contributions to U.S defined contribution plans by the Company	2,700	2,500	2,200
Pension Benefits
Defined Benefit Plan Disclosure
Unrecognized net loss in accumulated other comprehensive income	255,949	219,022
Net prior service cost in accumulated other comprehensive income	9,976	11,874
Net transition asset (obligation) in accumulated other comprehensive income	445	543
Net loss that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	23,513
Prior service cost that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	1,985
Net transition asset (obligation) that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	112
Plan contributions by employer	21,830	22,844
Estimated future employer contribution in next fiscal year	21,000
Expected benefits payments
2013	23,010
2014	23,874
2015	25,002
2016	26,250
2017	27,243
2018-2022	153,825
U.S. plans, Other Benefits
Defined Benefit Plan Disclosure
Unrecognized net loss in accumulated other comprehensive income	(8,082)
Net loss that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	(810)
Expected benefits payments
Benefit payments per year, including amounts to be paid out of Company assets and reflecting future expected services, for the next ten years	$ 1,100