Investments in Partially Owned Entities - Consolidated Variable Interest Entities ("VIEs") - Additional Information (Details) $ in Thousands	Mar. 31, 2020 USD ($) Property ApartmentUnit	Dec. 31, 2019 USD ($)
Variable Interest Entity [Line Items]
Properties | Property	306
Apartment units | ApartmentUnit	79,065
Total assets	$ 20,919,318	$ 21,172,769
Total liabilities	$ 9,795,290	10,164,843
Consolidated VIE [Member]
Variable Interest Entity [Line Items]
Properties | Property	16
Apartment units | ApartmentUnit	3,399
Total assets	$ 744,100	754,700
Total liabilities	$ 332,100	$ 323,100