Consolidated Statements of Shareholders' Equity (Parenthetical) (USD $) In Thousands	12 Months Ended
May 31, 2011	May 31, 2010	May 31, 2009
Consolidated Statements of Shareholders' Equity
Change in fair value of derivatives, tax expense (benefit)	$ 3,813	$ (260)	$ 94
Change in fair value of available-for-sale securities, tax expense (benefit)	$ 0	$ (14)	$ 50

Total tax effect of the change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges after taxes. The change includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 25

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