EQUITY AND MEZZANINE EQUITY - Additional Information (Details) - USD ($)			3 Months Ended		6 Months Ended
	Feb. 26, 2019	Dec. 14, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Equity
Noncontrolling interests - operating partnership (in shares)			1,224,000		1,224,000		1,368,000
Common stock outstanding (in shares)			11,656,000		11,656,000		11,942,000
Repurchase period		1 year
Remaining authorized repurchase amount			$ 17,700,000		$ 17,700,000
Preferred shares of beneficial interest, shares outstanding (in shares)			4,118,000		4,118,000		4,118,000
Preferred shares, liquidation preference (in dollars per share)			$ 25		$ 25		$ 25
Preferred shares, annual distribution accrual rate (in dollars per share)					$ 1.65625
Preferred shares, dividend rate					6.625%
Preferred shares liquidation preference			$ 102,971,000		$ 102,971,000		$ 102,971,000
Partnership units, converted (in shares)	1.37931
Conversion price (in dollars per share)	$ 72.50
Payments for acquisition of noncontrolling interests					$ 1,260,000	$ 0
Commons and Landing at Southgate Partnership
Equity
Noncontrolling interest acquired			34.50%		34.50%
Series D Preferred Units
Equity
Preferred units, shares issued (in shares)	165,600		166,000		166,000		0
Preferred units, par value (in dollars per share)	$ 100		$ 100		$ 100		$ 100
Distribution rate	3.862%
2015 Incentive Plan
Equity
Equity awards issued (in shares)			6,511	5,142	6,718	6,226
Total grant-date value shares issued			$ 447,000	$ 350,000	$ 457,000	$ 412,000
Share Repurchase Program
Equity
Aggregate gross sales price of common share of beneficial interest allowed to be repurchased		$ 50,000,000	$ 50,000,000		$ 50,000,000