Benefit Plans and Other Postretirement Benefits (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Expected benefits payments
Contributions to U.S defined contribution plans by the Company, maximum percentage of eligible compensation	5.00%
Matching contributions to U.S defined contribution plans by the Company	$ 3,000	$ 2,700	$ 2,500
Pension Benefits
Defined Benefit Plan Disclosure
Unrecognized net loss in Accumulated other comprehensive income	173,897	255,949
Net prior service cost in Accumulated other comprehensive income	13,628	9,976
Net transition asset (obligation) in Accumulated other comprehensive income	312	445
Net loss that will be amortized from Accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	16,181
Prior service cost that will be amortized from Accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	2,692
Net transition asset (obligation) that will be amortized from Accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	105
Plan contributions by employer	23,338	21,830	22,800
Estimated future employer contribution in next fiscal year	22,000
Expected benefits payments
2014	25,374
2015	26,233
2016	27,468
2017	28,387
2018	29,782
2019-2023	165,818
U.S. plans, Other Benefits
Defined Benefit Plan Disclosure
Unrecognized net loss in Accumulated other comprehensive income	3,935
Net loss that will be amortized from Accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	352
U.S. plans, Other Benefits | Minimum
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	1,000
U.S. plans, Other Benefits | Maximum
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