Derivative Financial Instruments - Schedule of Derivatives (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Derivative [Line Items]
Notional Amount	$ 231,053,000invest_DerivativeNotionalAmount		$ 181,119,000invest_DerivativeNotionalAmount
Fair Value Asset	114,000		260,000
Fair Value Liability	(798,000)		(11,000)
Changes in fair value of derivatives	(147,000)us-gaap_UnrealizedGainLossOnDerivatives	93,000us-gaap_UnrealizedGainLossOnDerivatives
Changes in fair value of derivatives	(933,000)	93,000
Changes in fair value of derivatives	(933,000)	93,000
Unrealized Loss on Cash Flow Hedge [Member]
Derivative [Line Items]
Changes in fair value of derivatives	(786,000)
Other (Loss) Income [Member]
Derivative [Line Items]
Changes in fair value of derivatives	(147,000)	93,000
Interest Rate Swaps [Member]
Derivative [Line Items]
Notional Amount	50,680,000		685,000
Fair Value Liability	(798,000)		(11,000)
Changes in fair value of derivatives	(787,000)	2,000
Interest Rate Caps [Member]
Derivative [Line Items]
Notional Amount	180,373,000		180,434,000
Fair Value Asset	114,000		260,000
Changes in fair value of derivatives	$ (146,000)	$ 91,000

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226000-175313

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5618551-113959

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (a),(c),(d),(e)

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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