Investments (Details) - Schedule of cost and equity method investments (USD $) In Millions, unless otherwise specified	Aug. 31, 2013	May 31, 2013	Aug. 31, 2012
Cost method investments:
Cost method investments	$ 4.7	$ 5.0	$ 5.5
Equity method investments:
Equity method investments	17.2	14.6	15.7
Total	21.9	19.6	21.2
UK Non-controlling [Member]
Cost method investments:
Cost method investments	4.7	5.0	5.5
UK Equity-method [Member]
Equity method investments:
Equity method investments	16.2	14.6	15.7
Software Development Business [Member]
Equity method investments:
Equity method investments	$ 1.0