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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The number of positions eliminated during the period as a result of restructuring activities.

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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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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Carrying amount as of the balance sheet date of known and estimated obligations associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid in the next twelve months or in the normal operating cycle if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

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Restructuring Restructuring Plan (Details) $ in Thousands	3 Months Ended								12 Months Ended
Restructuring Restructuring Plan (Details) $ in Thousands	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) employee	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0	$ 0	$ 0	$ 0	$ 286	$ 0	$ 0	$ 0	$ 0	$ 286
Restructuring Reserve, Current	185				273				$ 185	273
2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of Positions Eliminated (in employee) \| employee									7
Restructuring Reserve					273					273	$ 0
Restructuring charges									$ 0	300
Payments for Restructuring									(88)	(13)
Restructuring Reserve, Current	$ 185				$ 273				$ 185	$ 273