DEBT - Agreements (Detail)	1 Months Ended
	May. 31, 2015 USD ($)	Sep. 30, 2014 USD ($) item	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Nov. 02, 2015 USD ($)
Debt
Accrued interest and unused commitment fee payable			$ 1,865,000	$ 1,688,000
Principal payments on, and estimated amortization of debt
2016 (Nine Months Ending December 31, 2016)			110,286,000
2017			4,642,000
2018			24,300,000
2019			1,519,000
2020			1,596,000
Thereafter			520,450,000
Total Debt			662,793,000
Mortgages Payable
Principal payments on, and estimated amortization of debt
2016 (Nine Months Ending December 31, 2016)			3,286,000
2017			4,642,000
2018			24,300,000
2019			1,519,000
2020			1,596,000
Thereafter			108,380,000
Total Debt			143,723,000
Other debt
Principal payments on, and estimated amortization of debt
2016 (Nine Months Ending December 31, 2016)			107,000,000
Thereafter			412,070,000
Total Debt			519,070,000
Unsecured credit facility entered into in September 2014
Debt
Maximum borrowing capacity		$ 850,000,000
Upsized borrowing capacity		$ 1,150,000,000
Number of extension | item		2
Period of extension option		1 year
Amount outstanding under the facility			107,000,000	107,000,000
Amount available for future borrowings			$ 450,000,000	$ 450,000,000
Interest rate (as a percent)			1.58%	1.57%
Unsecured credit facility entered into in September 2014, revolver
Debt
Maximum borrowing capacity		$ 450,000,000
Unused commitment fee dependent upon amount of aggregate unused commitments, one (as a percent)		0.15%
Unused commitment fee dependent upon amount of aggregate unused commitments, two (as a percent)		0.25%
Amount outstanding under the facility			$ 0	$ 0
Unsecured credit facility entered into in September 2014, revolver | Base rate | Minimum
Debt
Interest rate margin (as a percent)		0.20%
Unsecured credit facility entered into in September 2014, revolver | Base rate | Maximum
Debt
Interest rate margin (as a percent)		1.00%
Unsecured credit facility entered into in September 2014, revolver | LIBOR | Minimum
Debt
Interest rate margin (as a percent)		1.20%
Unsecured credit facility entered into in September 2014, revolver | LIBOR | Maximum
Debt
Interest rate margin (as a percent)		2.00%
Unsecured credit facility entered into in September 2014, term loan
Debt
Maximum borrowing capacity		$ 325,000,000
Amount outstanding under the facility			107,000,000	107,000,000
Unsecured credit facility entered into in September 2014, term loan | Base rate | Minimum
Debt
Interest rate margin (as a percent)		0.15%
Unsecured credit facility entered into in September 2014, term loan | Base rate | Maximum
Debt
Interest rate margin (as a percent)		0.95%
Unsecured credit facility entered into in September 2014, term loan | LIBOR | Minimum
Debt
Interest rate margin (as a percent)		1.15%
Unsecured credit facility entered into in September 2014, term loan | LIBOR | Maximum
Debt
Interest rate margin (as a percent)		1.95%
Unsecured credit facility entered into in September 2014, delayed-draw term loan
Debt
Maximum borrowing capacity		$ 75,000,000
Unused line fee (as a percent)		0.25%
Unsecured term facility entered into in May 2015
Debt
Maximum borrowing capacity	$ 385,000,000
Unused line fee (as a percent)	0.20%
Amount outstanding under the facility			$ 385,000,000	$ 385,000,000
Interest rate (as a percent)			2.04%	1.84%
Prepayment fee	2.00%
Amount drawn under term loan					$ 385,000,000
Effective interest rate			3.16%
Unsecured term facility entered into in May 2015 | Base rate | Minimum
Debt
Interest rate margin (as a percent)	0.60%
Unsecured term facility entered into in May 2015 | Base rate | Maximum
Debt
Interest rate margin (as a percent)	1.25%
Unsecured term facility entered into in May 2015 | LIBOR | Minimum
Debt
Interest rate margin (as a percent)	1.60%
Unsecured term facility entered into in May 2015 | LIBOR | Maximum
Debt
Interest rate margin (as a percent)	2.25%