Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Taxes [Line Items]
Provision for income taxes	$ 13.2	$ 24.3	$ 19.0	$ 31.7
Number of years federal income tax returns are subject to examination			3 years
Period In Which Significant Changes In Unrecognized Tax Benefits Are Not Expected			next twelve months
U.S. Federal
Income Taxes [Line Items]
Income tax examination, start year			2013
Income tax examination, end year			2016
State and Local
Income Taxes [Line Items]
Income tax examination, start year			2012
Income tax examination, end year			2016
Foreign
Income Taxes [Line Items]
Income tax examination, start year			2009
Income tax examination, end year			2016