Summary of Investments in Real Estate (Parenthetical) (Detail) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Real Estate Properties [Line Items]
Investments in real estate, Book Value		$ 2,409,139	$ 2,517,645
Accumulated depreciation and amortization	[1]	209,096	198,326
IRT
Real Estate Properties [Line Items]
Investments in real estate, Book Value		1,314,115	1,372,015
Accumulated depreciation and amortization		$ 45,059	$ 39,638

[1] As of June 30, 2016, includes properties owned by Independence Realty Trust, Inc., or IRT, with a book value of $1,314,115 and accumulated depreciation of $45,059. As of December 31, 2015, includes properties owned by IRT, with a book value of $1,372,015 and accumulated depreciation of $39,638.