Components of Interest Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Banking and Thrift [Abstract]
Interest on borrowings and related fees	$ 22,808us-gaap_InterestExpenseBorrowings	$ 23,140us-gaap_InterestExpenseBorrowings
Amortization of debt issuance costs	1,104us-gaap_AmortizationOfFinancingCosts	1,012us-gaap_AmortizationOfFinancingCosts
Capitalized interest	(1,899)us-gaap_InterestPaidCapitalized	(1,618)us-gaap_InterestPaidCapitalized
Interest expense	$ 22,013us-gaap_InterestExpense	$ 22,534us-gaap_InterestExpense

Amount of noncash expense included in interest expense to issue debt and obtain financing associated with the related debt instruments. Alternate captions include noncash interest expense.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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- Definition

Aggregate amount of interest expense on all borrowings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

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- Definition

The amount of cash paid during the current period for interest that is capitalized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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