Condensed Consolidated Statement of Other Comprehensive Income Parenthetical (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Net gain (loss) on derivative instruments - tax effect:	$ 0	$ 0.3	$ 0.2	$ 0.3
Change in net unrealized gain on available-for-sale securities - tax effect:	(0.1)	(2.0)	0.1	(2.6)
Net change in cumulative foreign currency translation (loss) gain - tax effect:	$ 0.5	$ (0.2)	$ 1.8	$ 1.8