Stockholders' Equity - Cash Dividends Declared to Stockholders (Parenthetical) (Detail) (USD $)	Jul. 30, 2012
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend distribution rate	$ 0.125
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend distribution rate	$ 0.250

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Name:	us-gaap_DividendsPayableAmountPerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant