Subsequent Event (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	1 Months Ended
Dec. 31, 2012	Jan. 28, 2013 Share Repurchase
Subsequent Event [Line Items]
Authorized repurchase of outstanding common stock		$ 10.0
Remaining under previous share repurchase authorization	$ 0.3

The remaining repurchase amount authorized by an entity's Board of Directors under a stock repurchase plan.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration