Restructuring - Summary of Restructuring Activity (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Restructuring Cost And Reserve [Line Items]
Balance at January 1, 2018	$ 1,188
Charges to expense	119
Cash payments	(1,055)
Non-cash utilization	(16)
Balance at June 30, 2018	236
Employee Reduction [Member]
Restructuring Cost And Reserve [Line Items]
Balance at January 1, 2018	1,098
Charges to expense	31
Cash payments	(893)
Balance at June 30, 2018	236
Accelerated Depreciation [Member]
Restructuring Cost And Reserve [Line Items]
Charges to expense	16
Non-cash utilization	(16)
Other Exit Costs [Member]
Restructuring Cost And Reserve [Line Items]
Balance at January 1, 2018	90
Charges to expense	72
Cash payments	$ (162)