State or Country Name where an entity is incorporated

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- Definition

Accounting Policies [Line Items]

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- Definition

Excess Tax Benefit From Share Based Compensation Within Income Taxes Rather Than APIC

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- Definition

Maximum Individual Claims Liability Health Insurance

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- Definition

Maximum individual claims liability workers compensation insurance.

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- Definition

The aggregate of amounts due from customers or clients, within one year of the balance sheet date (or one operating cycle, if longer), for goods or services that have been delivered or sold in the normal course of business and an amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date within one year of the balance sheet, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection and net of any write-downs taken for collection uncertainty on the part of the holder, respectively.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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- Definition

Amount of the effect of a change in accounting principle on diluted earnings per share.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Glossary Retrospective Application
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- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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Description of Business, Basis of Presentation, and Significant Accounting Policies (Narrative) (Details) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 30, 2016 USD ($)	Nov. 30, 2015 USD ($)	Nov. 30, 2016 USD ($) segment $ / shares	Nov. 30, 2015 USD ($)	May 31, 2016 USD ($)	May 31, 2015 USD ($)
Accounting Policies [Line Items]
State of incorporation			Delaware
Number of reportable segments \| segment			1
Allowance for doubtful accounts	$ 6.0		$ 6.0		$ 4.2
Accounts receivable, net of allowance for doubtful accounts	528.9		528.9		408.6
Maximum individual workers' compensation claims liability			1.3		1.3
Maximum individual health insurance claims liability			0.3			$ 0.3
Stock-based compensation costs recognized	8.5	$ 8.7	17.6	$ 17.5
Excess tax benefit in income tax expense			$ 14.1
Diluted earnings per share increase \| $ / shares			$ 0.04
Trade Receivables [Member]
Accounting Policies [Line Items]
Accounts receivable, net of allowance for doubtful accounts	295.0		$ 295.0		221.6
Purchased Receivables [Member]
Accounting Policies [Line Items]
Accounts receivable, net of allowance for doubtful accounts	$ 233.9		$ 233.9		$ 187.0
Germany [Member] \| Total Revenue [Member] \| Geographic Concentration Risk [Member]
Accounting Policies [Line Items]
Percentage of total revenue less than one percent			1.00%	1.00%