Restructuring - Schedule of Restructuring Accruals Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Beginning balance	$ 3,893	$ 6,636
Restructuring expenses	8,455	3,674	$ 11,239
Payments, utilization and other	(8,168)	(6,417)
Ending balance	$ 4,180	$ 3,893	$ 6,636