CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 34,259	$ 29,843	$ 63,667	$ 37,742
Other comprehensive income/(loss), before tax:
Foreign currency translation and other adjustments	(50)	(30,851)	(2,202)	(13,346)
Pension/postretirement curtailment		(518)		(518)
Amortization of pension liability adjustments:
Prior service credit	(1,105)	(1,113)	(2,210)	(2,227)
Net actuarial loss	1,118	1,291	2,239	2,588
Payments and amortization related to interest rate swaps included in earnings	(420)	54	(872)	234
Derivative valuation adjustment	(5,887)	2,211	(9,264)	7,926
Income taxes related to items of other comprehensive income/(loss):
Pension/postretirement curtailment		155		155
Amortization of pension liability adjustment	(4)	(53)	(9)	(108)
Payments related to interest rate swaps included in earnings	108	(13)	223	(56)
Derivative valuation adjustment	1,504	(530)	2,367	(1,902)
Comprehensive income	29,523	476	53,939	30,488
Comprehensive income /(loss) attributable to the noncontrolling interest	207	(48)	417	182
Comprehensive income attributable to the Company	$ 29,316	$ 524	$ 53,522	$ 30,306