Consolidated Statements of Capital (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				12 Months Ended
	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income	$ 36,903	$ 29,702	$ 49,640	$ 27,239	$ 172,055	$ 139,590	$ 57,516
Reversal of unrealized gains upon the sale of marketable securities					(1,767)	(1,082)	(4,286)
Changes in fair value of cash flow hedges and amortization of gain on settlement of swap					12,614	3,402	7,707
Changes in fair value of marketable securities					(1,556)	1,411	1,330
Issuance of common stock under:
Sale of common stock					138,366	357,720	323,931
Issuance of Series H Preferred							71,209
Redemptions of Series F Preferred							(25,000)
Redemptions of Series B Preferred							(78,800)
Distributions to noncontrolling interests					(18,488)	(16,691)	(16,963)
Essex Portfolio, L.P. [Member]
Balances		1,880,116		1,553,728	1,880,116	1,553,728	1,355,014
Net income	36,903	29,702	49,640	27,239	172,055	139,590	57,516
Reversal of unrealized gains upon the sale of marketable securities					(1,767)	(1,082)	(4,286)
Changes in fair value of cash flow hedges and amortization of gain on settlement of swap					12,614	3,402	7,707
Changes in fair value of marketable securities					(1,556)	1,411	1,330
Issuance of common stock under:
Stock and unit based compensation plans					7,244	4,675	8,412
Sale of common stock					138,366	357,720	323,931
Stock and unit based compensation costs					1,608	1,801	873
Issuance of Series H Preferred							71,209
Capital contributions						4,232
Redemptions of Series F Preferred							(25,000)
Redemptions of Series B Preferred							(78,800)
Redemptions					(5,711)	(6,986)	(5,387)
Distributions to noncontrolling interests					(8,016)	(6,957)	(6,052)
Distributions declared					(196,715)	(171,418)	(152,739)
Balances	1,998,238		1,880,116		1,998,238	1,880,116	1,553,728
Essex Portfolio, L.P. [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Balances		(68,231)		(71,962)	(68,231)	(71,962)	(76,713)
Net income					0	0	0
Reversal of unrealized gains upon the sale of marketable securities					(1,767)	(1,082)	(4,286)
Changes in fair value of cash flow hedges and amortization of gain on settlement of swap					12,614	3,402	7,707
Changes in fair value of marketable securities					(1,556)	1,411	1,330
Issuance of common stock under:
Stock and unit based compensation plans					0	0	0
Sale of common stock					0	0	0
Stock and unit based compensation costs					0	0	0
Issuance of Series H Preferred							0
Capital contributions						0
Redemptions of Series F Preferred							0
Redemptions of Series B Preferred							0
Redemptions					0	0	0
Distributions to noncontrolling interests					0	0	0
Distributions declared					0	0	0
Balances	(58,940)		(68,231)		(58,940)	(68,231)	(71,962)
Essex Portfolio, L.P. [Member] | Noncontrolling Interest [Member]
Balances		68,689		66,814	68,689	66,814	70,499
Net income					6,834	6,347	5,571
Reversal of unrealized gains upon the sale of marketable securities					0	0	0
Changes in fair value of cash flow hedges and amortization of gain on settlement of swap					0
Changes in fair value of marketable securities					0	0	0
Issuance of common stock under:
Stock and unit based compensation plans					0	0	0
Sale of common stock					0	0	0
Stock and unit based compensation costs					0	0	0
Issuance of Series H Preferred							0
Capital contributions						4,232
Redemptions of Series F Preferred							0
Redemptions of Series B Preferred							0
Redemptions					(1,377)	(1,747)	(3,204)
Distributions to noncontrolling interests					(8,016)	(6,957)	(6,052)
Distributions declared					0	0	0
Balances	66,130		68,689		66,130	68,689	66,814
Essex Portfolio, L.P. [Member] | General Partner [Member] | Common Equity [Member]
Balances		1,762,856		1,439,089	1,762,856	1,439,089	1,202,751
Balances (in shares)		36,443,000		33,888,000	36,443,000	33,888,000	31,325,000
Net income					150,811	119,812	42,317
Reversal of unrealized gains upon the sale of marketable securities					0	0	0
Changes in fair value of cash flow hedges and amortization of gain on settlement of swap					0	0	0
Changes in fair value of marketable securities					0	0	0
Issuance of common stock under:
Stock and unit based compensation plans					7,244	4,675	8,412
Stock and unit based compensation plan (in shares)					65,000	151,000	103,000
Sale of common stock					138,366	357,720	323,931
Sale of common stock (in shares)					913,000	2,404,000	2,460,000
Stock and unit based compensation costs					(907)	(430)	(725)
Stock and unit based compensation costs (in shares)					0	0	0
Issuance of Series H Preferred							0
Issuance of Series H Preferred (in shares)							0
Capital contributions						0
Redemptions of Series F Preferred							(588)
Redemptions of Series F Preferred (in shares)							0
Redemptions of Series B Preferred							1,200
Redemption of Series B Preferred (in shares)							0
Redemptions					(3,717)	(1,798)	(1,134)
Distributions to noncontrolling interests					0	0	0
Distributions declared					(180,771)	(156,212)	(137,075)
Balances	1,873,882		1,762,856		1,873,882	1,762,856	1,439,089
Balances (in shares)	37,421,000		36,443,000		37,421,000	36,443,000	33,888,000
Essex Portfolio, L.P. [Member] | General Partner [Member] | Preferred Equity [Member]
Balances		71,209		71,209	71,209	71,209	24,412
Net income					5,472	5,472	4,753
Reversal of unrealized gains upon the sale of marketable securities					0	0	0
Changes in fair value of cash flow hedges and amortization of gain on settlement of swap					0	0	0
Changes in fair value of marketable securities					0	0	0
Issuance of common stock under:
Stock and unit based compensation plans					0	0	0
Sale of common stock					0	0	0
Stock and unit based compensation costs					0	0	0
Issuance of Series H Preferred							71,209
Capital contributions						0
Redemptions of Series F Preferred							(24,412)
Redemptions of Series B Preferred							0
Redemptions					0	0	0
Distributions to noncontrolling interests					0	0	0
Distributions declared					(5,472)	(5,472)	(4,753)
Balances	71,209		71,209		71,209	71,209	71,209
Essex Portfolio, L.P. [Member] | Limited Partners [Member] | Common Equity [Member]
Balances		45,593		48,578	45,593	48,578	54,065
Balances (in shares)		2,122,000		2,229,000	2,122,000	2,229,000	2,201,000
Net income					8,938	7,959	3,225
Reversal of unrealized gains upon the sale of marketable securities					0	0	0
Changes in fair value of cash flow hedges and amortization of gain on settlement of swap					0	0	0
Changes in fair value of marketable securities					0	0	0
Issuance of common stock under:
Stock and unit based compensation plans					0	0	0
Stock and unit based compensation plan (in shares)					0	0	0
Sale of common stock					0	0	0
Sale of common stock (in shares)					0	0	0
Stock and unit based compensation costs					2,515	2,231	1,598
Stock and unit based compensation costs (in shares)					28,000	(107,000)	28,000
Issuance of Series H Preferred							0
Issuance of Series H Preferred (in shares)							0
Capital contributions						0
Redemptions of Series F Preferred							0
Redemptions of Series F Preferred (in shares)							0
Redemptions of Series B Preferred							0
Redemption of Series B Preferred (in shares)							0
Redemptions					(617)	(3,441)	(1,049)
Distributions to noncontrolling interests					0	0	0
Distributions declared					(10,472)	(9,734)	(9,261)
Balances	45,957		45,593		45,957	45,593	48,578
Balances (in shares)	2,150,000		2,122,000		2,150,000	2,122,000	2,229,000
Essex Portfolio, L.P. [Member] | Limited Partners [Member] | Preferred Equity [Member]
Balances		0		0	0	0	80,000
Net income					0	0	1,650
Reversal of unrealized gains upon the sale of marketable securities					0	0	0
Changes in fair value of cash flow hedges and amortization of gain on settlement of swap					0
Changes in fair value of marketable securities					0	0	0
Issuance of common stock under:
Stock and unit based compensation plans					0	0	0
Sale of common stock					0	0	0
Stock and unit based compensation costs					0	0	0
Issuance of Series H Preferred							0
Capital contributions						0
Redemptions of Series F Preferred							0
Redemptions of Series B Preferred							(80,000)
Redemptions					0	0	0
Distributions to noncontrolling interests					0	0	0
Distributions declared					0	0	(1,650)
Balances	$ 0		$ 0		$ 0	$ 0	$ 0