Real Estate Investments Real Estate Investments - Acquisitions And Sales Of Real Estate (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2018 USD ($) community unit	Dec. 31, 2017 USD ($) community unit
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit		166
Purchase Price		$ 35,400
Investment in real estate	$ 13,366,101	13,366,101
Encumbrance	$ 1,806,626	1,806,626
Land and Land Improvements [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price		20,500
Building and Improvements [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price		47,800
Prepaid Expenses and Other Assets [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price		2,700
Marquis [Member]
Schedule of Equity Method Investments [Line Items]
Limited partnership interest in partnership investments	49.90%
Cash payments to acquire membership interests	$ 4,700
Consideration transferred, equity instruments	7,900
Investment in real estate	71,000	71,000
Encumbrance	$ 45,800	$ 45,800
Apartment Building [Member]
Schedule of Equity Method Investments [Line Items]
Number of communities acquired | community		1	2
Number of units acquired | unit		166	1,328
Purchase Price		$ 35,400	$ 273,000
Apartment Building [Member] | Marquis [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit		166
Purchase Price		$ 35,400
Essex Ownership Percentage	100.00%	100.00%