Individually Significant Dispositions - Additional Information (Details) $ in Thousands		9 Months Ended		12 Months Ended
	Oct. 23, 2015 USD ($) Property	Sep. 30, 2017 USD ($) Property ApartmentUnit	Sep. 30, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposed Properties | Property		4
Disposed Units | ApartmentUnit		1,024
Proceeds From Sale Of Property | $		$ 353,150
Starwood Portfolio [Member] | Disposal Group, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposed Properties | Property	72
Disposed Units	23,262
Proceeds From Sale Of Property | $	$ 5,365,000
Percentage of consolidated NOI			1.60%	15.70%