Subsequent Event - Additional Information (Detail) (Subsequent Event, Repurchase of Equity Units [Member], USD $) In Millions, unless otherwise specified	1 Months Ended
Jul. 29, 2013
Subsequent Event \| Repurchase of Equity Units [Member]
Subsequent Event [Line Items]
Authorized repurchase of outstanding common stock	$ 20.0

Amount of a stock repurchase plan authorized by an entity's Board of Directors.

No definition available.

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