Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net periodic benefit cost [Abstract]
Total amount amortized out of accumulated other comprehensive income	$ 3,001	$ 3,691
Defined contribution plan expense	11,358	9,808
U.S. Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	3,021	3,478
Interest cost	5,429	5,762
Expected return on plan assets	(9,953)	(9,698)
Prior service cost (credit)	107	183
Recognized actuarial gain	1,396	1,609
Transition obligation	0	0
Net periodic expense	0	1,334
Foreign Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	1,317	1,373
Interest cost	1,264	1,375
Expected return on plan assets	(1,804)	(1,948)
Prior service cost (credit)	(110)	(99)
Recognized actuarial gain	841	665
Transition obligation	1	1
Net periodic expense	1,509	1,367
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	618	740
Interest cost	1,019	1,317
Prior service cost (credit)	1,102	1,567
Recognized actuarial gain	(298)	(140)
Net periodic expense	2,441	3,484
Post-Retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	8	13
Interest cost	73	105
Prior service cost (credit)	2	(36)
Recognized actuarial gain	(40)	(59)
Net periodic expense	$ 43	$ 23