Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 133,383	$ 83,019	$ 32,585
Other comprehensive income/(loss), before tax:
Foreign currency translation adjustments	(8,747)	(27,383)	44,162
Pension/postretirement settlements and curtailments	450	1,494
Pension/postretirement plan remeasurement	(1,796)	851	2,955
Amortization of pension liability adjustments:
Prior service credit	(4,420)	(4,454)	(4,453)
Net actuarial loss	4,480	5,175	5,439
Payments and amortization related to interest rate swaps included in earnings	(1,011)	(146)	1,490
Derivative valuation adjustment	(9,512)	3,832	325
Income taxes related to items of other comprehensive income/(loss):
Pension/postretirement settlements and curtailments	(74)	(348)
Pension/postretirement plan remeasurement	359	(408)	(918)
Amortization of pension liability adjustments	(13)	(158)	(22)
Payments and amortization related to interest rate swaps included in earnings	259	37	(566)
Derivative valuation adjustment	2,432	(979)	(124)
Comprehensive income	115,790	60,532	80,873
Comprehensive income/(loss) attributable to the noncontrolling interest	975	111	(520)
Comprehensive income attributable to the Company	$ 114,815	$ 60,421	$ 81,393