SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION Reconciliation of Real Estate Properties (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance at beginning of year	$ 1,819,053us-gaap_RealEstateGrossAtCarryingValue	$ 1,287,198us-gaap_RealEstateGrossAtCarryingValue	$ 897,370us-gaap_RealEstateGrossAtCarryingValue
Other improvements	162,827us-gaap_RealEstateImprovements	112,622us-gaap_RealEstateImprovements	65,480us-gaap_RealEstateImprovements
Property acquisitions	299,793us-gaap_RealEstateOtherAcquisitions	272,661us-gaap_RealEstateOtherAcquisitions	324,348us-gaap_RealEstateOtherAcquisitions
Property dispositions	(73,078)us-gaap_RealEstateCostOfRealEstateSold	0us-gaap_RealEstateCostOfRealEstateSold	0us-gaap_RealEstateCostOfRealEstateSold
Consolidation of previously unconsolidated investments	0us-gaap_RealEstateOtherAdditions	146,572us-gaap_RealEstateOtherAdditions	0us-gaap_RealEstateOtherAdditions
Balance at end of year	$ 2,208,595us-gaap_RealEstateGrossAtCarryingValue	$ 1,819,053us-gaap_RealEstateGrossAtCarryingValue	$ 1,287,198us-gaap_RealEstateGrossAtCarryingValue

Amount of real estate investments sold for entities with a substantial portion of business acquiring and holding investment real estate.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule III)

-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 28

-Article 12

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph c

-Subparagraph Schedule III

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 970

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-28.4)

-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

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- Definition

Amount, before accumulated depreciation, of real estate investments for entities with a substantial portion of business acquiring and holding investment real estate.

+ References

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- Definition

Amount of increase in real estate investments related to improvements for entities with a substantial portion of business acquiring and holding investment real estate.

+ References

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase in real estate investments from acquisitions other than through foreclosure for entities with a substantial portion of business acquiring and holding investment real estate.

+ References

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Balance Type:	debit
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- Definition

Amount of other additions excluding acquisition or improvement to real estate investments for entities with a substantial portion of business acquiring and holding investment real estate.

+ References

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Balance Type:	na
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