Subsequent Events - Additional Information (Detail) (July 2013 Program, USD $) In Millions, unless otherwise specified		1 Months Ended
Jun. 30, 2013	Jul. 22, 2013 Subsequent Event
Subsequent Event [Line Items]
Shares authorized for repurchase		$ 300
Shares repurchase program end date	Jul. 22, 2016

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