Goodwill and Other Intangibles - Schedule of activity in goodwill (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Nov. 30, 2018	Nov. 30, 2017	May 31, 2018	May 31, 2017
Goodwill [Roll Forward]
Gross goodwill			$ 158.8	$ 158.5
Accumulated impairment	$ (39.6)	$ (39.6)	(39.6)	$ (39.6)
Beginning balance	119.2	118.9	118.9
Foreign currency translation	(0.1)	0.2	0.2
Other	0.0	0.0	0.1
Ending balance	$ 119.1	$ 119.1	$ 119.2

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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Amount of increase (decrease), classified as other, of an asset representing the future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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