Retirement Benefits - Pretax Amounts Recognized in Accumulated Other Comprehensive Income Loss (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Pension Benefits | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Net gain (loss) in current year	$ 5,971
Prior service cost	(182)
Amortization of prior service cost (credit)	27
Amortization of net loss (gain)	2,046
Exchange rate effect on amounts in other comprehensive income	0
Total	7,862
Pension Benefits | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Net gain (loss) in current year	(4,829)
Prior service cost	2
Amortization of prior service cost (credit)	(22)
Amortization of net loss (gain)	1,367
Exchange rate effect on amounts in other comprehensive income	(1,758)
Total	(5,240)
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Net gain (loss) in current year	(3,241)
Prior service cost	2,905
Amortization of prior service cost (credit)	(37)
Amortization of net loss (gain)	(504)
Exchange rate effect on amounts in other comprehensive income	2
Total	$ (875)