DEBT - Narrative (Details)	3 Months Ended
	Mar. 31, 2019 USD ($) property loan extension	Dec. 31, 2018 USD ($)
Line of Credit Facility [Line Items]
Number of real estate properties | property	88
Number of real estate properties, unencumbered by mortgages | property	40
Number of real estate properties, unencumbered used to provide credit support | property	30
Maximum borrowing capacity	$ 6,000,000
Revolving lines of credit	118,677,000	$ 57,500,000
Line of Credit
Line of Credit Facility [Line Items]
Revolving lines of credit	4,500,000	$ 0
Line of Credit | BMO Line of Credit
Line of Credit Facility [Line Items]
Current borrowing capacity	204,400,000
Remaining borrowing capacity	85,700,000
Revolving lines of credit	118,700,000
Line of Credit | BMO Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 250,000,000
Number of extensions | extension	1
Extension term	12 months
Minimum | London Interbank Offered Rate (LIBOR) | Line of Credit
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.35%
Minimum | Base Rate | Line of Credit
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.35%
Maximum | London Interbank Offered Rate (LIBOR) | Line of Credit
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.90%
Maximum | Base Rate | Line of Credit
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.85%
Mortgages
Line of Credit Facility [Line Items]
Number of real estate properties, serving as collateral for mortgage loans | property	48
Number of material defaults or instances of noncompliance | loan	0
Line of Credit
Line of Credit Facility [Line Items]
Term	1 year
Unsecured Debt | Term Loan Maturing 2024
Line of Credit Facility [Line Items]
Debt instrument face amount	$ 70,000,000
Unsecured Debt | Term Loan Maturing 2025
Line of Credit Facility [Line Items]
Debt instrument face amount	$ 75,000,000.0