Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net periodic benefit cost [Abstract]
Total amount amortized out of accumulated other comprehensive income	$ 3,691	$ 5,788
Defined contribution plan expense	9,808	9,006
U.S. Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	3,478	3,915
Interest cost	5,762	5,791
Expected return on plan assets	(9,698)	(10,393)
Prior service cost (income)	183	224
Recognized actuarial (gain) loss	1,609	3,155
Transition obligation	0	0
Other	0	810
Net periodic benefit cost	1,334	3,502
Foreign Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	1,373	1,688
Interest cost	1,375	1,486
Expected return on plan assets	(1,948)	(2,019)
Prior service cost (income)	(99)	23
Recognized actuarial (gain) loss	665	675
Transition obligation	1	9
Other	0	2
Net periodic benefit cost	1,367	1,864
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	740	935
Interest cost	1,317	1,266
Prior service cost (income)	1,567	1,732
Recognized actuarial (gain) loss	(140)	71
Net periodic benefit cost	3,484	4,004
Post-Retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	13	41
Interest cost	105	128
Prior service cost (income)	(36)	(93)
Recognized actuarial (gain) loss	(59)	(8)
Net periodic benefit cost	$ 23	$ 68