Aggregate number of apartment units owned as of the balance sheet date.

No definition available.

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- Definition

This element represents a description of the nature of common ownership or management control relationships with other entities, regardless of there being transactions between the entities, when the existence of that control could result in operating results or financial position of the reporting entity significantly different from that which would have been obtained if the entities' were autonomous.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Management And Other Fees From Affiliates

+ References

No definition available.

+ Details

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Namespace Prefix:	ess_
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Balance Type:	credit
Period Type:	duration

- Definition

Number of property units acquired during the period.

+ References

No definition available.

+ Details

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- Definition

The Preferred equity interest investment in a related party entity.

+ References

No definition available.

+ Details

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- Definition

Related Party Transaction, Revenues from Development and Redevelopment Fees

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Amount of gain (loss) on sale or disposal of an equity method investment.

+ References

No definition available.

+ Details

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- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35755396&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of cash paid for brokerage fees during the current period. This element is intended to represent the brokerage fees paid by and between financial industry participants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

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

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3213-108585

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Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3213-108585

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Balance Type:	credit
Period Type:	duration

- Definition

The percentage rate used to calculate dividend payments on preferred stock.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Amount of transactions with related party during the financial reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864

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-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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Related Party Transactions (Details) $ in Thousands	1 Months Ended					12 Months Ended
Related Party Transactions (Details) $ in Thousands	Aug. 31, 2015 USD ($) unit	Jun. 30, 2015 USD ($) apartment	Mar. 31, 2015 USD ($)	Jul. 31, 2014 USD ($) unit	Jan. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) apartment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2010 USD ($)
Related Party Transaction [Line Items]
Management and other fees from affiliates						$ 15,600	$ 16,500	$ 11,500
Revenues from development and redevelopment fees						6,700	7,200	4,400
Payments to acquire equity method investments			$ 1,300			127,879	246,006	162,578
Company's share of gain on the sales of co-investments						$ (469)	(6,558)	(41,252)
Apartment units owned \| apartment						59,160
Cash consideration for BRE merger						$ 0	555,826	0
Short term bridge loan						3,100	8,100
Gain on disposal of equity method investment	$ 1,500					$ (31,556)	$ (13,900)	0
Related party transaction, amount of transaction										$ 4,000
Limited partnership interest in partnership investments										3.00%
Anaheim, CA Multifamily Property [Member]
Related Party Transaction [Line Items]
Equity method investments			13,700
Company's share of gain on the sales of co-investments			$ 13,700
Cumulative dividend rate (in hundredths)			9.00%
MMI [Member]
Related Party Transaction [Line Items]
Payments for brokerage fees								$ 600	$ 400
Limited Liability Company [Member] \| Greentree Apartments [Member]
Related Party Transaction [Line Items]
Payments to acquire equity method investments		$ 10,000
Cumulative dividend rate (in hundredths)		9.50%
Apartment units owned \| apartment		220
Limited Liability Company [Member] \| Sterling Cove [Member]
Related Party Transaction [Line Items]
Payments to acquire equity method investments		$ 5,000
Cumulative dividend rate (in hundredths)		9.50%
Apartment units owned \| apartment		218
Limited Liability Company [Member] \| Alta Vista Apartments [Member]
Related Party Transaction [Line Items]
Payments to acquire equity method investments	$ 5,000
Cumulative dividend rate (in hundredths)	9.50%
Number of units in real estate property \| unit	92
Paragon Apartments [Member]
Related Party Transaction [Line Items]
Number of properties contributed \| unit				301
Cash consideration for BRE merger				$ 111,000
Marcus and Millichamp Company TMMC Affiliate [Member]
Related Party Transaction [Line Items]
Preferred equity interest investment in a related party entity					$ 8,600
Gain on disposal of equity method investment			$ 500