Stock Repurchase Program - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	6 Months Ended
Dec. 03, 2013	Apr. 30, 2014
Stock Repurchase Program [Line Items]
Stock repurchase program authorized amount	$ 500.0	$ 500.0
Remaining amount available for further repurchases		$ 420.3

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

No definition available.

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