CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Nov. 30, 2014	Nov. 30, 2013	Nov. 30, 2014	Nov. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 68.5us-gaap_NetIncomeLoss	$ 58.3us-gaap_NetIncomeLoss	$ 34.4us-gaap_NetIncomeLoss	$ 28.4us-gaap_NetIncomeLoss
Other comprehensive income (loss), net:
Foreign currency translation adjustments	(8.0)	3.0	(7.5)	(2.6)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	(2.0)	0.5	(1.5)	1.3
Total other comprehensive income (loss)	(10.0)	3.5	(9.0)	(1.3)
Comprehensive income (loss)	$ 58.5us-gaap_ComprehensiveIncomeNetOfTax	$ 61.8us-gaap_ComprehensiveIncomeNetOfTax	$ 25.4us-gaap_ComprehensiveIncomeNetOfTax	$ 27.1us-gaap_ComprehensiveIncomeNetOfTax

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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