| Subsequent Events - Additional Information (Detail) (Dividend Declared, USD $) | 1 Months Ended | 
|---|---|
| Apr. 25, 2013 | |
| Dividend Declared | |
| Subsequent Event [Line Items] | |
| Dividends declared per share | $ 0.10 | 
| Dividends declared, date | Apr. 25, 2013 | 
| Dividends declared, payable date | May 27, 2013 | 
| Dividends declared, record date | May 13, 2013 | 
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- Definition Dividends Declared Amount Per Share No definition available. 
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- Definition Date the declared dividend will be paid, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Date the dividend to be paid was declared, in CCYY-MM-DD format. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format. No definition available. 
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- Details 
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