Subsequent Events - Additional Information (Detail) (Subsequent Event [Member], USD $) In Millions, unless otherwise specified	1 Months Ended
Oct. 01, 2012
Subsequent Event [Line Items]
Increase of expenditure limit for the Company's Stock Repurchase Program	$ 25.0
Before Amendment
Subsequent Event [Line Items]
Stock Repurchase Program limit	275.0
After Amendment
Subsequent Event [Line Items]
Stock Repurchase Program limit	$ 300.0

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

No definition available.

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