Commitments and Contingencies (Details) $ in Millions	3 Months Ended
Mar. 31, 2018 USD ($) executive
Other Commitments [Line Items]
Unemployment benefits, possible liability with a change in control	$ 32.4
Unemployment benefits, possible liability without a change in control	13.0
Accrued severance benefits	$ 0.4
Number of executives \| executive	2
Minimum
Other Commitments [Line Items]
Period for providing minimum compensation salary and continuation of certain benefits to executives under employment agreements	6 months
Severance payment as a percentage of annual salary	100.00%
Severance payment as a percentage of annual bonus	50.00%
Maximum
Other Commitments [Line Items]
Period for providing minimum compensation salary and continuation of certain benefits to executives under employment agreements	3 years
Severance payment as a percentage of annual salary	300.00%
Severance payment as a percentage of annual bonus	300.00%

Employment Agreement, Severance, Percentage of Annual Bonus

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Employment Agreement, Severance, Percentage of Annual Salary

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Period for continuation of minimum compensation and benefits under certain executive employee agreements.

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Supplemental Unemployment Benefits, Number Of Executives

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Supplemental unemployment benefits for employees under contract that are terminated without good cause or the employee resigns for good reason following a change in control.

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Supplemental unemployment benefits for employees under contract that are terminated without good cause or the employee resigns for good reason in the absence of a change in control.

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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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Liability for amount due employees, in addition to wages and any other money that employers owe employees, when their employment ends through a layoff or other termination. For example, a company may provide involuntarily terminated employees with a lump sum payment equal to one week's salary for every year of employment.

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