Restructuring Charges - Roll-Forward of Accrued Restructuring Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2016			$ 1,062
Restructuring charges	$ 0	$ 1,642	0	$ 1,642
Payments			(157)
Accelerated depreciation			0
Accrued at June 30, 2016	905		905
Write-downs and retirements of fixed assets
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2016			228
Payments			0
Accelerated depreciation			0
Accrued at June 30, 2016	228		228
Lease cancellations
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2016			834
Payments			(157)
Accelerated depreciation			0
Accrued at June 30, 2016	$ 677		$ 677