| Subsequent Events - Additional Information (Detail) (USD $) | 3 Months Ended | 0 Months Ended | |
|---|---|---|---|
| Mar. 31, 2015 | Mar. 31, 2014 | Apr. 23, 2015 | |
| Subsequent Event [Line Items] | |||
| Dividends declared per share | $ 0.10us-gaap_CommonStockDividendsPerShareDeclared | $ 0.10us-gaap_CommonStockDividendsPerShareDeclared | |
| Dividends declared, date | Apr. 23, 2015 | ||
| Dividends declared, payable date | May 29, 2015 | ||
| Dividends declared, record date | May 15, 2015 | ||
| Subsequent Event [Member] | |||
| Subsequent Event [Line Items] | |||
| Dividends declared per share | $ 0.10us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember | ||
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- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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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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- Details 
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