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Derivative Instruments - Additional Information (Detail) (USD $)
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12 Months Ended | ||
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Dec. 31, 2013
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Dec. 31, 2012
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Dec. 31, 2011
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| Derivative [Line Items] | |||
| Interest rate swaps unrealized gains (losses) | $ (8,363,000) | $ (1,580,000) | $ (11,238,000) |
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Interest rate swaps [Member]
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| Derivative [Line Items] | |||
| Interest rate swaps realized losses | 9,900,000 | 9,600,000 | 39,000,000 |
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Interest rate swaps [Member] | Not Designated as Hedging Instrument [Member]
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| Derivative [Line Items] | |||
| Interest rate swaps unrealized gains (losses) | $ 8,363,000 | $ 1,580,000 | $ 11,238,000 |