Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax rate at which the deferred tax assets and liabilities are expected to reverse					21.00%
Tax Cuts And Jobs Act Of 2017, incomplete accounting, change in tax rate, deferred tax asset, provisional income tax expense					$ 41.1
Tax Cuts And Jobs Act Of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional tax			$ 290.0
Effective income tax rate, percent	30.60%	41.10%	114.50%	86.20%
Increase in effective foreign income tax rate			2.50%