| Subsequent Events - Monthly Distributions Declared by Company's Board of Directors (Detail) (USD $) | 1 Months Ended | 
|---|---|
| Oct. 08, 2013 | |
| Subsequent Event A [Member] | |
| Subsequent Event [Line Items] | |
| Record Date | Oct. 22, 2013 | 
| Payment Date | Oct. 31, 2013 | 
| Distribution per Common Share | $ 0.12 | 
| Subsequent Event B [Member] | |
| Subsequent Event [Line Items] | |
| Record Date | Nov. 14, 2013 | 
| Payment Date | Nov. 29, 2013 | 
| Distribution per Common Share | $ 0.12 | 
| Subsequent Event C [Member] | |
| Subsequent Event [Line Items] | |
| Record Date | Dec. 16, 2013 | 
| Payment Date | Dec. 31, 2013 | 
| Distribution per Common Share | $ 0.12 | 
| Subsequent Event [Member] | |
| Subsequent Event [Line Items] | |
| Distribution per Common Share | $ 0.36 | 
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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 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 
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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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