| 
           Employee Benefit Plans  (Details) (USD $) 
        In Millions, unless otherwise specified  | 
        12 Months Ended | 13 Months Ended | 16 Months Ended | ||
|---|---|---|---|---|---|
| 
           May 31, 2013 
         | 
        
           May 31, 2012 
         | 
        
           May 31, 2011 
         | 
        
           Feb. 01, 2012 
         | 
        
           May 31, 2013 
         | 
      |
| Employee Benefit Plans (Textual) [Abstract] | |||||
| Maximum percentage of salary deferral under 401(k) plan | 50.00% | ||||
| Company contributions to the plan | $ 13.1 | $ 10.3 | $ 3.5 | ||
| Amounts accrued under deferred compensation plans | $ 10.7 | $ 9.2 | $ 10.7 | ||
| Percentage of eligible pay that is matched by the employer | 50.00% | ||||
| Percentage of employee pay eligible for employer matching contribution | 4.00% | 6.00% | |||
| Percentage of annual base salary that eligible employees can defer under Deferred Compensation Plan | 50.00% | ||||
| Percentage of board cash compensation that may be deferred under Deferred Compensation Plan | 100.00% | ||||
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- Definition 
          Defined contribution plan employee contribution percentage maximum. No definition available. 
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- Definition 
          Percentage of the employee's match-eligible pay that is matched by the employer. No definition available. 
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- Details 
          
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- Definition 
          Employees deferred compensation plans deferred percentage maximum. No definition available. 
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- Definition 
          Outside directors deferred compensation plans deferred percentage maximum. No definition available. 
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- Definition 
          The carrying amount of the liability as of the balance sheet date to an individual under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          The amount of the cost recognized during the period for defined contribution plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. No definition available. 
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