Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Effective tax rates	(370.00%)	20.00%	(3.00%)	25.00%
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 29.3		$ 29.3			$ 19.7
Reduction in provision for income taxes due to impact of effective tax rate	25.8		25.8
Deferred tax assets classified as other non-current assets	318.2		318.2			$ 227.2
Deferred tax assets, valuation allowance	21.9		21.9
Other Noncurrent Liabilities
Income Tax Contingency [Line Items]
Increase in unrecognized tax benefits is reasonably possible	8.9		8.9
Other Noncurrent Assets
Income Tax Contingency [Line Items]
Unrecognized tax benefits	20.4		20.4
Accounting Standards Update 2016-09
Income Tax Contingency [Line Items]
Increase to deferred tax assets	43.6		43.6
Effective income tax rate reconciliation, share-based compensation, excess tax benefit	$ 32.8		$ 68.8
Retained Earnings | Accounting Standards Update 2016-09
Income Tax Contingency [Line Items]
Cumulative effect adjustment to retained earnings					$ 43.6