Other Income Tax - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Internal Revenue Service (IRS)
Income Tax - Additional Information
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Benefit			$ 31.5
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Deferred Tax Liability, Provisional Income Tax Benefit			97.9
Tax Cuts and Jobs Act of 2017, Accounting Complete		false
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense		$ 11.5	$ 66.4
Tax Year 2017
Income Tax - Additional Information
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	$ 266.5