Equity - Noncontrolling Interests Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) entity shares	Dec. 31, 2019 USD ($)
Noncontrolling Interest [Line Items]
Non-managing member unitholders	$ 199,158	$ 204,355
Noncontrolling Interests
Noncontrolling Interest [Line Items]
Non-managing members DownREIT units outstanding (in shares) | shares	5,000,000
Conversion of DownREIT units (in shares) | shares	7,000,000
Number of DownREIT LLCs (in entities) | entity	7
Non-managing member unitholders	$ 199,000
DownREIT unit, fair value	$ 221,000