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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Amount expected to be recognized in earnings for the specified restructuring cost.

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Discloses the amount charged against the accrued restructuring reserves, or earnings if not previously accrued, during the period for the specified type of restructuring cost.

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

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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 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 Expenses (Details) $ in Millions		3 Months Ended
Restructuring Expenses (Details) $ in Millions	Feb. 15, 2017 Employee	Mar. 31, 2017 USD ($)	Mar. 31, 2018 USD ($)	Mar. 02, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring expected cost				$ 1.5
Number of positions eliminated \| Employee	100
Employee severance
Restructuring Cost and Reserve [Line Items]
Restructuring expected cost		$ 3.8
Restructuring expenses paid		2.1
Facility-related cost
Restructuring Cost and Reserve [Line Items]
Facility-related costs incurred		0.0
Accrued severance and related expenses \| Employee severance
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, unpaid balance in accrued compensation		$ 1.7	$ 1.4