Significant Transactions - Summary of Apartment Community Dispositions (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) Property apartment_home Community	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) Property apartment_home Community	Sep. 30, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on dispositions of real estate | $	$ 1,146	$ 626,232	$ 356,929	$ 679,738
Wholly And Partially Owned Consolidated Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Apartment communities sold | Property	124		124
Apartment homes sold | apartment_home	33,682		33,682
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Wholly And Partially Owned Consolidated Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Apartment communities sold | Property	8		8
Apartment homes sold | apartment_home	2,605		2,605
Gain on dispositions of real estate | $			$ 356,929
Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Apartment communities sold | Community	0		0