Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax expense (benefit)	$ 2.9	$ 17.0	$ 5.1	$ 23.9
Cash and Cash Equivalents, at Carrying Value	$ 226.6	$ 202.7	226.6	$ 202.7	$ 203.0	$ 274.6
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount			$ 3.5
Effective tax rate	7.10%	28.60%	5.10%	27.40%
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax expense (benefit)	$ (9.6)		$ (25.5)
Non-US [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 65.0		$ 65.0