Subsequent Event (Details)	Apr. 29, 2019 USD ($)	Apr. 02, 2019 USD ($) properties unit	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Subsequent Event [Line Items]
Contract purchase price			$ 2,889,077,000	$ 2,886,585,000
Bridge Loan
Subsequent Event [Line Items]
Other Commitment	$ 0
Subsequent Event | Bridge Loan
Subsequent Event [Line Items]
Other Commitment		$ 450,000,000
Subsequent Event | Multifamily Properties | April 2019 Agreement of Sale Portfolio
Subsequent Event [Line Items]
Number of properties in portfolio to be acquired | properties		7
Number of units in portfolio to be acquired | unit		2,113
Contract purchase price		$ 461,000,000