Pension and Other Postretirement Benefits (Details 3) - Pensions [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 404,543	$ 381,064
Fair value of plan assets	333,913	313,461
U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	352,062	334,808
Fair value of plan assets	298,966	282,213
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	52,481	46,256
Fair value of plan assets	$ 34,947	$ 31,248