Benefit Plans and Other Postretirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Change in plan assets:
Employer contributions	$ 21,800	$ 22,800	$ 17,300
Pension Benefits
Defined Benefit Plan Disclosure
Number of U.S. defined benefit pension plans	2
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	488,609	457,321
Service cost	9,175	7,832
Interest cost	22,021	22,684	23,100
Plan amendments	271
Actuarial (gain) loss	66,617	27,642
Foreign exchange translation	4,604	(2,450)
Benefits paid	(25,939)	(24,420)
Projected benefit obligation at end of year	565,358	488,609	457,321
Change in plan assets:
Fair value of plan assets at the beginning of the year	295,054	296,530
Actual return on plan assets	38,022	(2,001)
Employer contributions	21,830	22,844
Foreign exchange translation	1,982	(2,131)
Benefits paid	(22,465)	(20,188)
Fair value of plan assets at the end of the year	334,423	295,054	296,530
Funded status	(230,935)	(193,555)
Accumulated benefit obligation	541,093	469,547
Components of net periodic benefit cost:
Service cost	7,714	7,073	5,907
Interest cost	22,021	22,684	23,100
Expected return on plan assets	(24,951)	(25,226)	(28,016)
Net amortization of actuarial losses	20,454	14,528	17,051
Net pension expense	25,238	19,059	18,042
International Plans
Change in projected benefit obligation:
Projected benefit obligation at end of year	70,000	48,000
Contribution required to be made during 2013, included in other accrued expenses	3,700
Other Postretirement Benefits
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	16,698	19,095
Service cost	179	198
Interest cost	677	843	786
Actuarial (gain) loss	(700)	(2,299)
Benefits paid	(1,141)	(1,139)
Projected benefit obligation at end of year	15,713	16,698	19,095
Components of net periodic benefit cost:
Service cost	179	198	165
Interest cost	677	843	786
Amortization of transition obligation	62	62	62
Net amortization of actuarial losses	965	1,291	882
Net pension expense	$ 1,883	$ 2,394	$ 1,895