Equity - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended		3 Months Ended		9 Months Ended				0 Months Ended													9 Months Ended	0 Months Ended
	Sep. 15, 2014	Mar. 31, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 15, 2014	Dec. 31, 2013	Jan. 17, 2014 Liberty Apartments [Member]	Aug. 15, 2014 Dimmock Square [Member]	Jul. 10, 2014 Common Stockholders [Member]	Apr. 10, 2014 Common Stockholders [Member]	Jan. 09, 2014 Common Stockholders [Member]	Oct. 09, 2014 Common Stockholders [Member] Subsequent Event [Member]	Jul. 10, 2014 Common Unitholders [Member]	Apr. 10, 2014 Common Unitholders [Member]	Jan. 09, 2014 Common Unitholders [Member]	Oct. 09, 2014 Common Unitholders [Member] Subsequent Event [Member]	Oct. 09, 2014 Common Stock [Member] Subsequent Event [Member]	Oct. 09, 2014 Capital Units [Member] Subsequent Event [Member]	Aug. 04, 2014 Dividend Declared [Member]	Sep. 30, 2014 Dividend Declared [Member]	Nov. 10, 2014 Dividend Declared [Member] Subsequent Event [Member]
Class of Stock [Line Items]
Shares issued through public offering	5,750,000
Per share value of stock issued							$ 9.05
Net proceeds from public offering	$ 49,300				$ 49,566	$ 203,245
Authorized capital shares of common stock			500,000,000		500,000,000			500,000,000
Authorized capital shares of preferred stock			100,000,000		100,000,000			100,000,000
Shares of common stock issued			25,018,733		25,018,733			19,163,413
Shares of common stock outstanding			25,018,733		25,018,733			19,163,413
Preferred stock issued			0		0			0
Preferred stock outstanding			0		0			0
Percentage of Operating Partnership held			62.90%		62.90%			59.50%
Acquisition, common units issued									695,652	990,952
Common units in exchange for all noncontrolling interests		30,000
Aggregate cash dividends and distributions, paid					$ 15,729	$ 2,578					$ 3,100	$ 3,100	$ 3,100	$ 4,000	$ 2,200	$ 2,200	$ 2,100	$ 2,400	$ 4,000	$ 2,400
Cash dividend/distribution, date declared																						Aug. 04, 2014	Nov. 10, 2014
Cash dividend/distribution per share, declared			$ 0.16	$ 0.16	$ 0.48	$ 0.24															$ 0.16		$ 0.16
Cash dividend/distribution, date payable																						Oct. 09, 2014	Jan. 08, 2015
Cash dividend/distribution, date of record																						Oct. 01, 2014	Dec. 30, 2014