Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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New Accounting Pronouncements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Nov. 30, 2016	Nov. 30, 2016	May 31, 2016
New Accounting Pronouncement, Early Adoption, Effect \| Accounting Standards Update 2016-09
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in income taxes	$ 2.4	$ 19.6
Stock based compensation expense	1.3	3.0
New Accounting Pronouncement, Early Adoption, Effect \| Accounting Standards Update 2016-09 \| Additional Paid-in Capital
New Accounting Pronouncement, Early Adoption [Line Items]
Cumulative effect adjustment	(26.7)	(26.7)
New Accounting Pronouncement, Early Adoption, Effect \| Accounting Standards Update 2016-09 \| Retained Earnings
New Accounting Pronouncement, Early Adoption [Line Items]
Cumulative effect adjustment	$ 26.7	$ 26.7
Other Assets \| Accounting Standards Update 2015-03
New Accounting Pronouncement, Early Adoption [Line Items]
Debt issuance costs			$ 5.6
Long Term Liabilities \| Accounting Standards Update 2015-03
New Accounting Pronouncement, Early Adoption [Line Items]
Debt issuance costs			$ (5.6)