Income Taxes (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Operating Loss Carryforwards [Line Items]
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Liability, Provisional Income Tax Benefit	$ 4.6
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Elimination Of Alternative Minimum Tax, Provisional Income Tax Benefit	6.7
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense	6.5
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 136.5