Pension and Other Postretirement Benefits - Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Net actuarial loss (gain), beginning of year	$ 56,746
Amortization of actuarial gain (loss)	(2,930)
Actuarial loss	42,048
Asset gain	(16,113)
Settlement loss recognized	(3,153)		$ (1,300)
Divestitures and acquisitions	335
Currency impact	3,738
Net actuarial loss (gain), end of year	80,671	$ 56,746
Prior service cost, beginning of year	2,661
Amortization of prior service cost	(190)	(169)	42
Prior service cost occurring during the year	226
Currency impact	101
Prior service cost, end of year	2,798	2,661
Other Benefits
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Net actuarial loss (gain), beginning of year	(600)
Amortization of actuarial gain (loss)	59
Actuarial loss	110
Asset gain	0
Settlement loss recognized	0
Divestitures and acquisitions	0
Currency impact	(5)
Net actuarial loss (gain), end of year	(436)	(600)
Prior service cost, beginning of year	0
Amortization of prior service cost	0	0	$ 0
Prior service cost occurring during the year	0
Currency impact	0
Prior service cost, end of year	$ 0	$ 0