Share Repurchase Plan - Additional Information (Detail) (USD $) In Millions, unless otherwise specified		1 Months Ended
Sep. 30, 2012	Jun. 18, 2012 Maximum [Member]
Share repurchase plan		$ 100
Shares repurchased	0

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