BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reclassifications (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rental and other property operating	$ (62,928,000)	$ (79,917,000)	$ (101,268,000)
Other assets	9,222,000	18,469,000
Increase to net cash provided by (used in) operating activities	$ 40,985,000	61,456,000	(2,724,000)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tenant reimbursements		9,039,000	9,264,000
Tenant reimbursements, non-lease		984,000	7,382,000
Rental and other property operating		254,000	317,000
Interest expense to loss on early extinguishment of debt		808,000	1,854,000
Accounting Standards Update 2016-15
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gain on sale of real estate to loss on early extinguishment of debt			6,361,000
Other assets		272,000	1,579,000
Increase to net cash provided by (used in) operating activities		$ 1,307,000	$ 1,579,000