Subsequent Event - Additional Information (Detail) (Subsequent event [Member], USD $) In Thousands, unless otherwise specified	1 Months Ended
Apr. 25, 2013
Subsequent event [Member]
Subsequent Event [Line Items]
Authorized amount of common stock for repurchase	$ 20,000

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