Organization and Basis of Presentation - Accumulated Other Comprehensive Loss - Partnership (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	$ 6,337,023
Balance at period end	6,183,902
Essex Portfolio, L.P. [Member] | AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(39,598)
Other comprehensive (loss) income before reclassification	(3,399)
Amounts reclassified from accumulated other comprehensive loss	5,380
Other comprehensive income (loss)	1,981
Balance at period end	(37,617)
Essex Portfolio, L.P. [Member] | Change in fair value and amortization of swap settlements
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(46,087)
Other comprehensive (loss) income before reclassification	(4,775)
Amounts reclassified from accumulated other comprehensive loss	8,256
Other comprehensive income (loss)	3,481
Balance at period end	(42,606)
Essex Portfolio, L.P. [Member] | Unrealized gains on available for sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	6,489
Other comprehensive (loss) income before reclassification	1,376
Amounts reclassified from accumulated other comprehensive loss	(2,876)
Other comprehensive income (loss)	(1,500)
Balance at period end	$ 4,989