Average Share Price

No definition available.

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- Definition

Equity Method Investment Ownership Percentage By Partners, Increase During Period

+ References

No definition available.

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- Definition

Number of units acquired.

+ References

No definition available.

+ Details

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- Definition

The number of units sold by the entity during the period.

+ References

No definition available.

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- Definition

Number of units to be developed by the joint venture in the future.

+ References

No definition available.

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- Definition

Real Estate, Number Of Floors To Be Developed

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No definition available.

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- Definition

Sale of Stock, Average Sales Price Per Share

+ References

No definition available.

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- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

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- Details

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- Definition

In a business combination achieved in stages, this element represents the amount of gain recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination.

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-Publisher FASB

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-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)(2)

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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-Subparagraph (SX 210.5-02.22(a)(1))

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

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- Definition

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2443-110228

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

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- Definition

The cash outflow from the acquisition of a piece of land, anything permanently fixed to it, including buildings, structures on it and so forth; includes real estate intended to generate income for the owner; excludes real estate acquired for use by the owner.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

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Balance Type:	credit
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- Definition

The cash inflow from the additional capital contribution to the entity.

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

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-Publisher FASB

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-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

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Balance Type:	debit
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- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

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- Definition

Cash received for the sale of real estate that is not part of an investing activity during the current period.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (c)

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- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (b)

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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- Definition

Number of new stock issued during the period.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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-Subparagraph (SX 210.3-04)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

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- Definition

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

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Significant Transactions During the First Quarter of 2015 and Subsequent Events (Details) (USD $)	3 Months Ended		1 Months Ended			0 Months Ended	1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jan. 31, 2015 unit	Feb. 28, 2015	Mar. 31, 2015 unit sqft	Mar. 31, 2015	May 08, 2015 apartment	May 04, 2015
Acquisitions [Abstract]
Acquisitions of real estate	$ 199,190,000us-gaap_PaymentsToAcquireRealEstate	$ 33,825,000us-gaap_PaymentsToAcquireRealEstate
Borrowings under debt agreements	756,562,000	233,780,000
Repayment of debt	536,830,000us-gaap_RepaymentsOfLongTermDebt	312,585,000us-gaap_RepaymentsOfLongTermDebt
Proceeds from Issuance of Common Stock	174,592,000	157,596,000
Sale of common stock	184,158,000
Common Stock [Member]
Acquisitions [Abstract]
Sale of common stock (in shares)	822,071
Average share price (in dollars per share)	$ 225.51
Proceeds from Issuance of Common Stock	184,200,000
Pinnacle South Mountain [Member]
Acquisitions [Abstract]
Number of units sold			552
Sales of real estate			63,800,000
Gain on sale of property			4,700,000
Equity Method Investments [Member] \| Folsom 500 [Member]
Acquisitions [Abstract]
Acquisitions of real estate				43,600,000
Equity Method Investments [Member] \| Eighth And Hope [Member]
Acquisitions [Abstract]
Acquisitions of real estate				200,000,000
Area of real estate property				4,000
Number of units acquired				290
Equity Method Investments [Member] \| Station Park Green [Member]
Acquisitions [Abstract]
Acquisitions of real estate					67,000,000
Number of units to be developed	599				599	599
Area of real estate property	35,000				35,000	35,000
Equity Method Investments [Member] \| The Huxley And The Dylan [Member]
Acquisitions [Abstract]
Additional interest acquired					50.00%
Cash consideration for BRE merger					100,100,000
Gain on remeasurement of co-investment						21,400,000
Equity Method Investments [Member] \| Wesco I Reveal [Member] \| Subsequent Event [Member]
Acquisitions [Abstract]
Number of units acquired							438
Cash consideration for BRE merger							73,000,000
Percentage of voting interests acquired							49.50%
Equity Method Investments [Member] \| San Francisco, CA [Member] \| Folsom 500 [Member]
Acquisitions [Abstract]
Number of floors to be developed				42
Number of units to be developed				545
Area of real estate property				5,900
Ownership percentage (in hundredths)	50.00%				50.00%	50.00%
Unsecured Debt [Member] \| Senior Unsecured Notes Maturing April 1, 2025 [Member]
Acquisitions [Abstract]
Borrowings under debt agreements					500,000,000
Interest rate, stated percentage	3.50%				3.50%	3.50%
Unsecured Line of Credit [Member]
Acquisitions [Abstract]
Repayment of debt					1,000,000,000
Line of Credit Working Capital [Member]
Acquisitions [Abstract]
Repayment of debt					25,000,000
Common Stock [Member]
Acquisitions [Abstract]
Sale of common stock (in shares)	822,000
Common Stock [Member] \| Subsequent Event [Member]
Acquisitions [Abstract]
Sale of common stock (in shares)								34,125
Sale of common stock								$ 7,800,000
Shares issued, price per share								$ 229.50