Interest and Other Expense, net (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Interest and Other Income, net [Abstract]
Interest and investment expense, net	$ (29.7)	$ (33.9)	$ (13.2)
Loss on foreign currency	(3.3)	0.0	(3.9)
Gain (loss) on strategic investments	0.3	3.8	(23.3)
Other income	8.5	8.5	2.7
Interest and other expense, net	$ (24.2)	$ (21.6)	$ (37.7)