Pensions and Other Postretirement Benefit Plans (Schedule of Plan Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning of year	$ 211,755	$ 178,942
Actual return on plan assets, net of expenses	28,477	32,367
Employer contributions	3,219	4,670
Plan participants' contributions	198	243
Benefits paid	(8,123)	(8,404)
Settlements	(737)	(260)
Foreign currency changes	4,262	4,197
Fair value of plan assets, end of year	239,051	211,755
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets, net of expenses	0	0
Employer contributions	3,555	3,782
Plan participants' contributions	0	0
Benefits paid	(3,555)	(3,782)
Settlements	0	0
Foreign currency changes	0	0
Fair value of plan assets, end of year	$ 0	$ 0