Noncontrolling Interest (Details) (Operating Partnership, Noncontrolling Interest - Unit holders in Operating Partnership)	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common Units
Noncontrolling interest
Ownership interest held by noncontrolling owners (as a percent)	5.07%	3.64%	13.35%
Noncontrolling interest
Balance, beginning of period (in shares)	2,431,849	6,898,650
Redemptions from Common Units to Common Stock		(5,105,584)
Issuance/grant	1,035,745	719,572
Redemption of Common Units for cash	(2,400)	(80,789)
Balance, end of period (in shares)	3,465,194	2,431,849
Other Noncontrolling Common Units
Noncontrolling interest
Balance, beginning of period (in shares)	1,124,813	6,299,186
Conversions from LTIP units to Common Units		12,000
Redemptions from Common Units to Common Stock		(5,105,584)
Issuance/grant	812,676
Redemption of Common Units for cash	(2,400)	(80,789)
Balance, end of period (in shares)	1,935,089	1,124,813
LTIP Units
Noncontrolling interest
Balance, beginning of period (in shares)	1,307,036	599,464
Conversions from LTIP units to Common Units		(12,000)
Issuance/grant	223,069	719,572
Balance, end of period (in shares)	1,530,105	1,307,036

Represents the number of noncontrolling common units redeemed for cash.

No definition available.

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- Definition

Number of new units issued during the period. Also includes units issued under share-based compensation awards.

+ References

No definition available.

+ Details

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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- Definition

Number of shares issued which are neither cancelled nor held in the treasury.

+ References

No definition available.

+ Details

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- Definition

Number of shares issued during the period as a result of the conversion of convertible securities.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29-30)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Number of stock bought back by the entity at the exercise price or redemption price.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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