Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (258,601)
Ending balance	(168,079)
Loss on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,298)
Other comprehensive income before reclassification	0
Amounts reclassified from accumulated other comprehensive loss	646
Net current period other comprehensive income	646
Ending balance	(1,652)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,401)
Other comprehensive income before reclassification	(1,264)
Amounts reclassified from accumulated other comprehensive loss	0
Net current period other comprehensive income	(1,264)
Ending balance	(3,665)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(4,699)
Other comprehensive income before reclassification	(1,264)
Amounts reclassified from accumulated other comprehensive loss	646
Net current period other comprehensive income	(618)
Ending balance	$ (5,317)