Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 97,243	$ 133,383	$ 83,019
Other comprehensive income/(loss), before tax:
Foreign currency translation and other adjustments	38,927	(8,747)	(27,383)
Pension settlements and curtailments	411	450	1,494
Pension/postretirement plan remeasurement	13,407	(1,796)	851
Amortization of pension and postretirement liability adjustments:
Prior service credit	(4,474)	(4,420)	(4,454)
Net actuarial loss	5,004	4,480	5,175
Payments and amortization related to interest rate swaps included in earnings	3,982	(1,011)	(146)
Derivative valuation adjustment	(12,622)	(9,512)	3,832
Income taxes related to items of other comprehensive income/(loss):
Pension settlements and curtailments	(128)	(74)	(348)
Pension/postretirement plan remeasurement	(3,017)	359	(408)
Amortization of pension and postretirement liability adjustments	(148)	(13)	(158)
Payments and amortization related to interest rate swaps included in earnings	(1,028)	259	37
Derivative valuation adjustment	3,259	2,432	(979)
Comprehensive income	140,816	115,790	60,532
Comprehensive income/(loss) attributable to the noncontrolling interest	(207)	975	111
Comprehensive income attributable to the Company	$ 141,023	$ 114,815	$ 60,421