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Defined Contribution Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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May 31, 2014 | May 31, 2013 | May 31, 2012
401(k) [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Required years of service for plan eligibility (years) | 1 year |  |
Total contributions to defined benefit plans | $ 33.7 | $ 28.4 | $ 26.0
Deferred Profit Sharing Plan (DPSP) [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total contributions to defined benefit plans | 1.6 | 1.4 | 1.3
Supplemental Executive Retirement Plan (SERP) [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total contributions to defined benefit plans | $ 6.0 | $ 4.7 | $ 5.7

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- Definition Defined Contribution Plan, Eligibility, Required Years of Service + References No definition available. + Details
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- Definition The increase in the fair value of plan assets from contributions made by the employer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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- Details
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