Investments in Real Estate - Additional Information (Detail) $ / shares in Units, $ in Thousands				3 Months Ended		9 Months Ended
		Sep. 17, 2015 USD ($)	May. 01, 2015 USD ($) State	Sep. 30, 2015 USD ($) $ / shares	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) Property $ / shares shares	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Real Estate Properties [Line Items]
Investments in real estate	[1]			$ 2,259,750		$ 2,259,750		$ 1,671,971
Mortgages or other debt held by third parties				799,436		799,436		641,874
Mortgages held by consolidated securitizations				831,554		831,554		878,856
Gains (losses) on IRT merger with TSRE		$ 64,012		64,012		64,012
Investment contributed revenue				55,459	$ 41,806	164,321	$ 116,204
Net income allocable to common shares				(6,532)	$ (23,266)	5,327	$ (63,503)
Fair value of assets acquired						5,662
Business acquisitions purchase price allocation subsequent adjustments				72		$ 72
Number of parcels of land disposed | Property						2
Deferred gain on sale of real estate property						$ 3,111
Impairment of real estate asset				7,250
Multi-family real estate properties | Deconsolidated
Real Estate Properties [Line Items]
Carrying value of asset held for sale				23,897		$ 23,897
Multi-family real estate properties
Real Estate Properties [Line Items]
Number of real estate properties disposed | Property						3
Sales price of real estate properties						$ 88,537
Gain on sale of real estate property						$ 24,711
TSRE
Real Estate Properties [Line Items]
Number of real estate properties acquired | Property						19
Indebtedness		359,495
Series of Individually Immaterial Business Acquisitions
Real Estate Properties [Line Items]
Indebtedness				$ 359,495		$ 359,495
Investments in acquisition of real estate						288,382
Investment contributed revenue						3,811
Net income allocable to common shares						$ 1,696
Series of Individually Immaterial Business Acquisitions | Multi-family real estate properties
Real Estate Properties [Line Items]
Number of real estate properties acquired | Property						19
IRT
Real Estate Properties [Line Items]
Conversion of outstanding common stock to cash | $ / shares				$ 3.80		$ 3.80
Conversion of outstanding common stock to shares				41.08%		41.08%
Common stock issued in connection with merger | shares						15,100,000
Gains (losses) on IRT merger with TSRE						$ 34,000
Investments in acquisition of real estate			$ 25,250
IRT | Indiana
Real Estate Properties [Line Items]
Number of real estate properties acquired | State			236
IRT | Working Capital And Intangible Assets
Real Estate Properties [Line Items]
Investments in acquisition of real estate			$ 25,250
IRT | TSRE
Real Estate Properties [Line Items]
Common stock issued in connection with merger | shares						1,925,419
Gains (losses) on IRT merger with TSRE						$ 30,000
Indebtedness				$ 359,495		359,495
Business Combination Indebtedness Paid-off				237,610		237,610
Business Combination Outstanding Indebtedness				121,885		121,885
Acquisition Expenses						12,530
Extinguishing financing expenses						23,219
Employee separation expenses						4,289
Investments in acquisition of real estate		$ 263,636
Land
Real Estate Properties [Line Items]
Investments in real estate				404,565		404,565		338,057
Real estate and Improvements
Real Estate Properties [Line Items]
Investments in real estate				$ 2,043,766		$ 2,043,766		$ 1,502,394

[1] Investments in real estate includes one real estate asset held for sale by IRT as of September 30, 2015. This asset had a carrying amount of $3,283 and a fair value of $3,350.