Pension and Other Postretirement Benefits (Details 5) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Accrued liabilities	$ 6,318	$ 8,044
Accrued retirement benefits	98,171	93,358
Pensions [Member]
Defined Benefit Plan Disclosure [Line Items]
Other assets	15,604	12,454
Accrued liabilities	3,204	2,977
Accrued retirement benefits	67,426	64,626
Accumulated other non-owner changes to equity, net	(138,083)	(140,968)
Net actuarial loss	(136,096)	(139,098)
Prior service costs	(1,987)	(1,870)
Pensions [Member] | U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Other assets	5,698	2,212
Accrued liabilities	3,204	2,977
Accrued retirement benefits	49,892	49,618
Accumulated other non-owner changes to equity, net	(118,951)	(122,109)
Net actuarial loss	(117,409)	(119,908)
Prior service costs	(1,542)	(2,201)
Pensions [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other assets	9,906	10,242
Accrued liabilities	0	0
Accrued retirement benefits	17,534	15,008
Accumulated other non-owner changes to equity, net	(19,132)	(18,859)
Net actuarial loss	(18,687)	(19,190)
Prior service costs	(445)	331
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued liabilities	3,114	5,067
Accrued retirement benefits	29,990	28,172
Accumulated other non-owner changes to equity, net	(4,036)	(3,079)
Net actuarial loss	(3,979)	(2,981)
Prior service costs	$ (57)	$ (98)