Condensed Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (92,281)	$ 51,626	$ (55,848)	$ 96,614
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	1,024	3,335	5,395	5,403
Interest rate swaps – net change in deferred loss	(2,130)	(1,946)	(4,698)	(9,079)
Pension – net change in deferred actuarial loss	49	38	97	75
Other comprehensive (loss) income, net of tax	(1,057)	1,427	794	(3,601)
Comprehensive (loss) income	$ (93,338)	$ 53,053	$ (55,054)	$ 93,013