Pension and Other Postretirement Benefits (Details 5) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Accrued liabilities	$ 8,618	$ 8,294
Accrued retirement benefits	104,302	89,000
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other assets	7,705	15,287
Accrued liabilities	3,204	3,230
Accrued retirement benefits	75,920	55,729
Accumulated other non-owner changes to equity, net	(135,974)	(98,006)
Net actuarial loss	(133,238)	(95,973)
Prior service costs	(2,736)	(2,033)
Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other assets	0	4,242
Accrued liabilities	2,826	2,823
Accrued retirement benefits	62,893	41,410
Accumulated other non-owner changes to equity, net	(121,927)	(84,990)
Net actuarial loss	(119,601)	(82,736)
Prior service costs	(2,326)	(2,254)
Pension Plan [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other assets	7,705	11,045
Accrued liabilities	378	407
Accrued retirement benefits	13,027	14,319
Accumulated other non-owner changes to equity, net	(14,047)	(13,016)
Net actuarial loss	(13,637)	(13,237)
Prior service costs	(410)	221
Other postretirement benefit plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued liabilities	5,414	5,064
Accrued retirement benefits	27,662	32,506
Accumulated other non-owner changes to equity, net	(2,716)	(5,838)
Net actuarial loss	(2,618)	(5,746)
Prior service costs	$ (98)	$ (92)