Pension (Pre-tax Amounts Recognized in Accumulated Other Comprehensive Loss) (Details) - Pension Plan - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 110,606	$ 116,907
Prior service cost (credit)	(2,635)	(2,467)
Total cost (credit)	107,971	114,440
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	98,228	105,830
Prior service cost (credit)	1	237
Total cost (credit)	98,229	106,067
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	12,378	11,077
Prior service cost (credit)	(2,636)	(2,704)
Total cost (credit)	$ 9,742	$ 8,373