Accumulated Other Comprehensive (Loss) Income - Activity in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 680,477	$ 641,987	$ 706,755	$ (186,924)
Other comprehensive loss	(3,493)	(4,021)	(4,462)	(4,959)
Ending balance	1,855,657	642,817	1,855,657	642,817
Accumulated other comprehensive loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(13,484)	(1,168)	(12,515)	(230)
Ending balance	(16,977)	(5,189)	(16,977)	(5,189)
Pension and other postretirement benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(7,503)	(6,627)	(8,027)	(7,126)
Other comprehensive loss	527	498	1,051	997
Ending balance	(6,976)	(6,129)	(6,976)	(6,129)
Pension and other postretirement benefits, gain (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive (loss) income, before reclassifications, before tax	518	491	1,034	979
Other comprehensive (loss) income, before reclassifications, tax	0	0	0	0
Other comprehensive (loss) income, before reclassifications	518	491	1,034	979
Pension and other postretirement benefits, prior service cost
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amount reclassified from AOCI to net income/loss	9	7	17	18
Less: Tax expense	0	0	0	0
Net amount reclassified from AOCI to net income	9	7	17	18
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,101)	6,845	(3,322)	8,318
Other comprehensive loss, before tax	(2,257)	(4,723)	(1,036)	(6,196)
Less: Tax expense	0	0	0	0
Other comprehensive loss	(2,257)	(4,723)	(1,036)	(6,196)
Ending balance	(4,358)	2,122	(4,358)	2,122
Cash flow hedge derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,880)	(1,386)	(1,166)	(1,422)
Other comprehensive (loss) income, before reclassifications, before tax	(1)	(74)	(3,985)	(388)
Other comprehensive (loss) income, before reclassifications, tax	0	30	0	46
Other comprehensive (loss) income, before reclassifications	(1)	(104)	(3,985)	(434)
Ending balance	(5,643)	(1,182)	(5,643)	(1,182)
Cash flow hedge derivatives | Interest expense
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Net amount reclassified from AOCI to net income	(2)	308	0	674
Cash flow hedge derivatives | Foreign currency exchange (loss) gain, net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Net amount reclassified from AOCI to net income	$ (1,760)	$ 0	$ (492)	$ 0