Pension and Other Postretirement Benefits - Information About Accumulated and Projected Benefit Obligations In Excess of Plan Assets (Details) - Pension Plans, Defined Benefit [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract]
Projected Benefit Obligation	$ 130,549	$ 170,745
Accumulated Benefit Obligation	125,525	167,139
Fair Value of Plan Assets	98,622	136,041
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets [Abstract]
Projected Benefit Obligation	130,549	170,745
Fair Value of Plan Assets	98,622	136,041
Domestic [Member]
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract]
Projected Benefit Obligation	12,197	67,254
Accumulated Benefit Obligation	11,456	66,676
Fair Value of Plan Assets	0	49,197
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets [Abstract]
Projected Benefit Obligation	12,197	67,254
Fair Value of Plan Assets	0	49,197
Foreign [Member]
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract]
Projected Benefit Obligation	118,352	103,491
Accumulated Benefit Obligation	114,069	100,463
Fair Value of Plan Assets	98,622	86,844
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets [Abstract]
Projected Benefit Obligation	118,352	103,491
Fair Value of Plan Assets	$ 98,622	$ 86,844