Summary of Disposition and Each Property's Contribution (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Real Estate Properties [Line Items]
Net income (loss) allocable to common shares	$ (7,580)	$ 18,956	$ (25,424)	$ 11,859
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations
Real Estate Properties [Line Items]
Sale Price			153,899
Gain (loss) on sale			37,865		$ 18
Net income (loss) allocable to common shares	546		$ 1,677
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | Multi family | Ventura
Real Estate Properties [Line Items]
Date of Sale			Mar. 30, 2016
Sale Price			$ 8,750
Gain (loss) on sale			119
Net income (loss) allocable to common shares			$ 36
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | Multi family | Desert Wind
Real Estate Properties [Line Items]
Date of Sale			May 18, 2016
Sale Price			$ 8,750
Gain (loss) on sale			(2,032)
Net income (loss) allocable to common shares	45		$ 50
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | Multi family | Las Vistas
Real Estate Properties [Line Items]
Date of Sale			May 18, 2016
Sale Price			$ 10,500
Gain (loss) on sale			(60)
Net income (loss) allocable to common shares	76		$ 113
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | Multi family | Penny Lane
Real Estate Properties [Line Items]
Date of Sale			May 18, 2016
Sale Price			$ 10,000
Gain (loss) on sale			3,248
Net income (loss) allocable to common shares	52		$ 90
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | Multi family | Sandal Ridge
Real Estate Properties [Line Items]
Date of Sale			May 18, 2016
Sale Price			$ 12,250
Gain (loss) on sale			3,482
Net income (loss) allocable to common shares	75		$ 133
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | Multi family | Silversmith
Real Estate Properties [Line Items]
Date of Sale			Jun. 03, 2016
Sale Price			$ 6,200
Gain (loss) on sale			1,227
Net income (loss) allocable to common shares	50		$ 98
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | Office | Mineral Or Lincoln
Real Estate Properties [Line Items]
Date of Sale			Mar. 25, 2016
Sale Price			$ 7,949
Gain (loss) on sale			(374)
Net income (loss) allocable to common shares			$ (1)
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | Land | Saxony
Real Estate Properties [Line Items]
Date of Sale			Apr. 06, 2016
Sale Price			$ 1,500
Gain (loss) on sale			(14)
Net income (loss) allocable to common shares			$ (4)
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | IRT | Multi family | Cumberland Glen
Real Estate Properties [Line Items]
Date of Sale			Feb. 18, 2016
Sale Price			$ 18,000
Gain (loss) on sale			2,454
Net income (loss) allocable to common shares			$ 99
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | IRT | Multi family | Belle Creek
Real Estate Properties [Line Items]
Date of Sale			Apr. 07, 2016
Sale Price			$ 23,000
Gain (loss) on sale			14,401
Net income (loss) allocable to common shares	31		$ 377
Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations | IRT | Multi family | Tresa
Real Estate Properties [Line Items]
Date of Sale			May 05, 2016
Sale Price			$ 47,000
Gain (loss) on sale			15,414
Net income (loss) allocable to common shares	$ 217		$ 686