Investments in Real Estate - Schedule of Details of Properties Acquired (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) Property
Real Estate Properties [Line Items]
Purchase Price | $	$ 1,520,603
Hotel [Member]
Real Estate Properties [Line Items]
Number of Properties	2
Multifamily [Member]
Real Estate Properties [Line Items]
Number of Properties	13
Industrial [Member]
Real Estate Properties [Line Items]
Number of Properties	39
Retail [Member]
Real Estate Properties [Line Items]
Number of Properties	1
CA [Member] | Hotel [Member] | Hyatt Place UC Davis [Member]
Real Estate Properties [Line Items]
Number of Properties	1
Acquisition Date	Jan. 31, 2017
Purchase Price | $	$ 32,687
CA [Member] | Hotel [Member] | Hyatt Place San Jose Downtown [Member]
Real Estate Properties [Line Items]
Number of Properties	1
Acquisition Date	Jun. 30, 2017
Purchase Price | $	$ 65,321
CA [Member] | Industrial [Member] | Stockton [Member]
Real Estate Properties [Line Items]
Number of Properties	1
Acquisition Date	Feb. 28, 2017
Purchase Price | $	$ 32,751
Mesa, AZ [Member] | Multifamily [Member] | Sonora Canyon [Member]
Real Estate Properties [Line Items]
Number of Properties	1
Acquisition Date	Feb. 28, 2017
Purchase Price | $	$ 40,983
Philadelphia, PA [Member] | Retail [Member] | Bakers Centre [Member]
Real Estate Properties [Line Items]
Number of Properties	1
Acquisition Date	Mar. 31, 2017
Purchase Price | $	$ 54,223
Various [Member] | Multifamily [Member] | TA Multifamily Portfolio [Member]
Real Estate Properties [Line Items]
Number of Properties	6
Acquisition Date	Apr. 30, 2017
Purchase Price | $	$ 432,593
Various [Member] | Industrial [Member] | HS Industrial Portfolio [Member]
Real Estate Properties [Line Items]
Number of Properties	38
Acquisition Date	Apr. 30, 2017
Purchase Price | $	$ 405,930
Atlanta, GA [Member] | Multifamily [Member] | Emory Point [Member]
Real Estate Properties [Line Items]
Number of Properties	1
Acquisition Date	May 31, 2017
Purchase Price | $	$ 201,578
NV [Member] | Multifamily [Member] | Nevada West [Member]
Real Estate Properties [Line Items]
Number of Properties	3
Acquisition Date	May 31, 2017
Purchase Price | $	$ 170,965
NV [Member] | Multifamily [Member] | Mountain Gate & Trails [Member]
Real Estate Properties [Line Items]
Number of Properties	2
Acquisition Date	Jun. 30, 2017
Purchase Price | $	$ 83,572