Commitments and Contingencies - Lease Exit Liability (Details) - Facility Closing - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment		$ (100)
Restructuring Reserve [Roll Forward]
Beginning balance	$ 1,354
Cash Payments	(419)
Ending balance	935
Expense	$ 5,200

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

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