CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 15,220	$ 13,409	$ 27,427	$ 36,826
Other comprehensive income/(loss), before tax:
Foreign currency translation adjustments	11,974	36	39,348	2,651
Pension/postretirement plan remeasurement				(170)
Amortization of pension liability adjustments:
Prior service credit	(1,113)	(1,113)	(3,339)	(3,338)
Net actuarial loss	1,350	1,296	4,050	3,870
Expense related to interest rate swaps included in earnings	295	1,100	1,238	1,686
Derivative valuation adjustment	(96)	497	(1,094)	(6,936)
Income taxes related to items of other comprehensive income/(loss):
Pension/postretirement plan remeasurement				65
Amortization of pension liability adjustment	(71)	(55)	(213)	(160)
Expense related to interest rate swaps included in earnings	(112)	(418)	(470)	(641)
Derivative valuation adjustment	36	(189)	415	2,636
Comprehensive income	27,483	14,563	67,362	36,489
Comprehensive income/(loss) attributable to the noncontrolling interest	(43)	340	221	(112)
Comprehensive income attributable to the Company	$ 27,526	$ 14,223	$ 67,141	$ 36,601