BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rental and other property expenses	$ (15,658)	$ (20,765)	$ (35,911)	$ (38,681)
Rental and other property income	22,419	37,825	56,000	72,969
Interest and other income	$ 4,888	3,559	$ 8,780	7,020
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Expense reimbursements		2,940		4,391
Non-lease component expense reimbursements		411		569
Rental and other property expenses		15		119
Interest and other income		411		569
Reclassified From Expense Reimbursements | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rental and other property income		2,940		4,391
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		$ 15		$ 119