EQUITY AND MEZZANINE EQUITY - Additional Information (Details) - USD ($)			3 Months Ended
	Dec. 05, 2019	Feb. 26, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Nov. 30, 2019	Dec. 31, 2018
Equity
Noncontrolling interests - operating partnership (in shares)			1,043,000		1,100,000		1,058,000
Common stock outstanding (in shares)			12,163,000		12,100,000		12,098,000
Sale of common shares, net			$ 3,352,000
Repurchase period	1 year
Remaining authorized repurchase amount			$ 46,900,000
Preferred shares of beneficial interest, shares outstanding (in shares)			4,000,000.0		4,100,000
Preferred shares, liquidation preference (in dollars per share)			$ 25.00
Preferred shares, annual distribution accrual rate (in dollars per share)			$ 1.65625
Preferred shares, dividend rate			6.625%
Preferred shares liquidation preference			$ 99,600,000
Partnership units, converted (in shares)		1.37931
Conversion price (in dollars per share)		$ 72.50
Series D Preferred Units
Equity
Preferred units, shares issued (in shares)		165,600	166,000				166,000
Preferred units, par value (in dollars per share)		$ 100	$ 100				$ 100
Distribution rate		3.862%
Share Repurchase Program
Equity
Aggregate gross sales price of common share of beneficial interest allowed to be repurchased	$ 50,000,000
At-The-Market Offering
Equity
Aggregate gross sales price of common shares			$ 124,300,000			$ 150,000,000.0
Common Shares of Beneficial interest, shares issued (in shares)			50,000
Average per share price of common shares issued (in dollars per share)			$ 68.04
Net consideration for common shares			$ 3,400,000
2015 Incentive Plan
Equity
Equity awards issued (in shares)			1,193	207
Sale of common shares, net			$ 125,000	$ 10,000