Accumulated Other Comprehensive Income (Loss) - Reclassification out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Less: Tax effect	$ (34.6)	$ (43.1)	$ 3.3	$ (19.2)
Net income (loss)	57.1	67.9	(6.6)	28.3
Amount reclassified from Accumulated other comprehensive income (loss) \| Retirement benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of unrecognized gain (loss) included in net periodic benefit (cost)	0.6	1.1	1.2	2.1
Settlement charge	(15.4)	0.0	(15.4)	0.0
Less: Tax effect	(6.3)	(0.4)	(6.4)	(0.7)
Net income (loss)	$ 9.7	$ 0.7	$ 10.2	$ 1.4

Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax

No definition available.

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- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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