Organization and Basis of Presentation - Accumulated Other Comprehensive Loss - Partnership (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	$ 6,403,504
Balance at period end	6,352,881
Essex Portfolio, L.P. | Accumulated Other Comprehensive Loss, Net
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(10,432)
Other comprehensive loss before reclassification	(1,222)
Amounts reclassified from accumulated other comprehensive loss	(3,769)
Other comprehensive loss	(4,991)
Balance at period end	(15,423)
Essex Portfolio, L.P. | Change in fair value and amortization of swap settlements
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(10,536)
Other comprehensive loss before reclassification	(952)
Amounts reclassified from accumulated other comprehensive loss	(3,769)
Other comprehensive loss	(4,721)
Balance at period end	(15,257)
Essex Portfolio, L.P. | Unrealized gain/(loss) on available for sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	104
Other comprehensive loss before reclassification	(270)
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive loss	(270)
Balance at period end	$ (166)