Organization and Basis of Presentation - Accumulated Other Comprehensive Loss (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	$ 6,183,192
Balance at period end	6,131,899
Accumulated Other Comprehensive Loss, Net
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(14,729)
Other comprehensive income before reclassification	5,750
Amounts reclassified from accumulated other comprehensive loss	11
Other comprehensive income	5,761
Balance at period end	(8,968)
Change in fair value and amortization of swap settlements
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(14,771)
Other comprehensive income before reclassification	5,406
Amounts reclassified from accumulated other comprehensive loss	11
Other comprehensive income	5,417
Balance at period end	(9,354)
Unrealized gain on available for sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	42
Other comprehensive income before reclassification	344
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive income	344
Balance at period end	386
Essex Portfolio, L.P. | Accumulated Other Comprehensive Loss, Net
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(11,303)
Other comprehensive income before reclassification	5,951
Amounts reclassified from accumulated other comprehensive loss	12
Other comprehensive income	5,963
Balance at period end	(5,340)
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	(11,346)
Other comprehensive income before reclassification	5,595
Amounts reclassified from accumulated other comprehensive loss	12
Other comprehensive income	5,607
Balance at period end	(5,739)
Essex Portfolio, L.P. | Unrealized gain on available for sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	43
Other comprehensive income before reclassification	356
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive income	356
Balance at period end	$ 399