Restructuring (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring accrual and changes
Charges	$ 1,108	$ 2,998
Accrued expenses
Restructuring accrual and changes
Balance at December 31, 2017	498
Charges	1,108
Payments	(616)
Other Adjustments1	990
Employment termination costs | Accrued expenses
Restructuring accrual and changes
Balance at December 31, 2017	474
Charges	1,108
Payments	(612)
Other Adjustments1	970
Facilities consolidation | Accrued expenses
Restructuring accrual and changes
Balance at December 31, 2017	24
Charges	0
Payments	(4)
Other Adjustments1	$ 20