BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rental and other property expenses	$ (13,286)	$ (20,405)	$ (49,197)	$ (59,086)
Rental and other property income	17,306	36,606	73,306	109,575
Interest and other income	$ 4,175	3,286	$ 12,955	10,306
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Expense reimbursements		1,857		6,248
Non-lease component expense reimbursements		272		841
Rental and other property expenses		33		152
Interest and other income		272		841
Reclassified From Expense Reimbursements | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rental and other property income		1,857		6,248
Reclassified From Rental And Other Property Expenses | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rental and other property income		$ 33		$ 152