Benefit Plans and Other Postretirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Benefits
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	$ 565,358	$ 488,609
Service cost	10,454	9,175
Interest cost	20,899	22,021	22,684
Acquisitions	16,371
Plan amendments	5,639	271
Actuarial (gain) loss	(33,700)	66,617
Foreign exchange translation	2,609	4,604
Benefits paid	(27,560)	(25,939)
Projected benefit obligation at end of year	560,070	565,358	488,609
Change in plan assets:
Fair value of plan assets at the beginning of the year	334,423	295,054
Actual return on plan assets	50,694	38,022
Employer contributions	23,338	21,830	22,800
Acquisitions	12,266
Foreign exchange translation	(623)	1,982
Benefits paid	(27,560)	(22,465)
Fair value of plan assets at the end of the year	392,538	334,423	295,054
Funded status	(167,532)	(230,935)
Accumulated benefit obligation	539,383	541,093
Components of net periodic benefit cost:
Service cost	8,502	7,714	7,073
Interest cost	20,899	22,021	22,684
Expected return on plan assets	(24,828)	(24,951)	(25,226)
Net amortization of actuarial losses	25,500	20,454	14,528
Net pension expense	30,073	25,238	19,059
International Plans
Change in projected benefit obligation:
Projected benefit obligation at end of year	74,000	70,000
Contribution required to be made during 2014, included in other accrued expenses	4,000
Other Postretirement Benefits
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	15,713	16,698
Service cost	160	179
Interest cost	511	677	843
Actuarial (gain) loss	(3,374)	(700)
Benefits paid	(1,080)	(1,141)
Projected benefit obligation at end of year	11,930	15,713	16,698
Components of net periodic benefit cost:
Service cost	160	179	198
Interest cost	511	677	843
Amortization of transition obligation		62	62
Net amortization of actuarial losses	773	965	1,291
Net pension expense	$ 1,444	$ 1,883	$ 2,394