Basic and Diluted Earnings Per Share (Details Textual) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2012	Nov. 30, 2011
Basic And Diluted Earnings Per Share (Textual)
Common stock issued related to exercises or vesting of stock-based awards	0.3	0	1.1	0.3

Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

No definition available.

Name:	us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration