Equity - Components of Accumulated Other Comprehensive (Loss) Income, Net of Tax (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive gains before reclassifications	$ 20.8
Amount reclassified from accumulated other comprehensive loss	0.0
Other comprehensive gains, net	20.8
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 31, 2016	(37.3)
Balance as of June 30, 2017	(16.5)
Unrealized Gains (Losses) on Available-for- Sale Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 31, 2016	16.6
Other comprehensive gains before reclassifications	1.6
Amount reclassified from accumulated other comprehensive loss	(0.1)
Other comprehensive gains, net	1.5
Balance as of June 30, 2017	18.1
Unrealized Gains (Losses) on Cash Flow Hedges [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 31, 2016	(4.5)
Other comprehensive gains before reclassifications	8.3
Amount reclassified from accumulated other comprehensive loss	0.1
Other comprehensive gains, net	8.4
Balance as of June 30, 2017	3.9
Foreign Currency Translation Adjustments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 31, 2016	(49.4)
Other comprehensive gains before reclassifications	10.9
Amount reclassified from accumulated other comprehensive loss	0.0
Other comprehensive gains, net	10.9
Balance as of June 30, 2017	$ (38.5)