Condensed Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 46,270	$ (92,281)	$ 26,683	$ (55,848)
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(60,015)	1,024	(39,468)	5,395
Interest rate swaps – net change in deferred gain or loss	3,684	(2,130)	13,798	(4,698)
Pension plans – net change in deferred actuarial loss	55	49	111	97
Other comprehensive (loss) income, net of tax	(56,276)	(1,057)	(25,559)	794
Comprehensive (loss) income	$ (10,006)	$ (93,338)	$ 1,124	$ (55,054)