Restructuring Charges - Roll-Forward of Accrued Restructuring Expense (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2017	$ 1,210
Payments	(470)
Accrued at March 31, 2017	740
Severance expenses [Member]
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2017	901
Payments	(445)
Accrued at March 31, 2017	456
Write-downs and retirements of fixed assets [Member]
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2017	228
Payments	0
Accrued at March 31, 2017	228
Lease cancellations [Member]
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2017	81
Payments	(25)
Accrued at March 31, 2017	$ 56