Repurchase of Common Stock - Additional Information (Detail)	Jun. 30, 2011
Equity, Class of Treasury Stock [Line Items]
Repurchase of common stock, additional authorized shares	6,590,301

Name:

us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased

Namespace Prefix:

us-gaap

Data Type:

xbrli:sharesItemType

Balance Type:

na

Period Type:

instant