Restructuring - Restructuring Reserve Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Restructuring Reserve [Roll Forward]
Beginning balance	$ 720	$ 0	$ 1,386	$ 0
Restructuring charges (recoveries)	6,893	104	6,602	104
Costs paid or otherwise settled	(2,965)	(33)	(3,340)	(33)
Ending balance	4,648	71	4,648	71
Facility related costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	720	0	1,386	0
Restructuring charges (recoveries)	6,454	0	6,163	0
Costs paid or otherwise settled	(2,965)	0	(3,340)	0
Ending balance	4,209	0	4,209	0
Personnel related costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	0	0	0	0
Restructuring charges (recoveries)	439	104	439	104
Costs paid or otherwise settled	0	(33)	0	(33)
Ending balance	$ 439	$ 71	$ 439	$ 71