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

Stock Repurchase Program - Additional Information (Detail) - shares	Oct. 31, 2016	Apr. 30, 2014
Stock Repurchase Program [Line Items]
Stock Repurchase Program Number Of Shares Authorized To Be Repurchased	0
Board Of Directors
Stock Repurchase Program [Line Items]
Stock Repurchase Program Number Of Shares Authorized To Be Repurchased		500,000