Stock Repurchase Program - Additional Information (Detail) In Millions, unless otherwise specified	3 Months Ended
Aug. 31, 2013
Stock Repurchase Programs [Line Items]
Authorization of stock repurchase program	Jan. 08, 2008
Shares repurchased	0
Minimum
Stock Repurchase Programs [Line Items]
Shares authorized to be repurchased, per year	1
Maximum
Stock Repurchase Programs [Line Items]
Shares authorized to be repurchased, per year	2

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

No definition available.

Name:	us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant