Investments in Real Estate - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2017 Investment Property
Real Estate Properties [Line Items]
Number of real estate investments | Investment	18
Number of real estate properties acquired	85
In-place Lease Intangibles [Member]
Real Estate Properties [Line Items]
Weighted-average acquired lease intangibles	3 years
Below-market Ground Lease Intangibles [Member]
Real Estate Properties [Line Items]
Weighted-average acquired lease intangibles	52 years
Above-market Lease Intangibles [Member]
Real Estate Properties [Line Items]
Weighted-average acquired lease intangibles	6 years
Below-market Lease Intangibles [Member]
Real Estate Properties [Line Items]
Weighted-average acquired lease intangibles	6 years
Prepaid Ground Lease Rent [Member]
Real Estate Properties [Line Items]
Weighted-average acquired lease intangibles	71 years
Other Intangibles {Member]
Real Estate Properties [Line Items]
Weighted-average acquired lease intangibles	4 years
Industrial [Member]
Real Estate Properties [Line Items]
Number of real estate properties acquired	50
Multifamily [Member]
Real Estate Properties [Line Items]
Number of real estate properties acquired	27
Retail [Member]
Real Estate Properties [Line Items]
Number of real estate properties acquired	1
Hotel [Member]
Real Estate Properties [Line Items]
Number of real estate properties acquired	7