Summary of Investments in Real Estate (Parenthetical) (Detail) $ in Thousands	Jun. 30, 2017 USD ($) Property	Dec. 31, 2016 USD ($) Property
Multifamily properties
Real Estate Properties [Line Items]
Carrying value of asset held for sale | $	$ 5,932	$ 62,428
Number of real estate properties held for sale | Property	1	3
Parcels of land
Real Estate Properties [Line Items]
Carrying value of asset held for sale | $	$ 14,586	$ 14,233
Number of real estate properties held for sale | Property	2	2