FAIR VALUE OF FINANCIAL INSTRUMENTS - Estimates of Fair Value Differ from Carrying Amounts (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable, net	$ 0	$ 313,812
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Note receivable	94,430	44,430
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Note receivable, fair value	97,372	43,322
Unsecured notes payable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred financing costs, net	8,152	10,094
Unsecured notes payable \| Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unsecured notes payable	1,502,901	1,503,435
Deferred financing costs, net	7,200	8,700
Unsecured notes payable \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	1,607,310	1,591,830
Variable rate debt \| Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Variable rate debt	327,694	327,171
Deferred financing costs, net	900	1,400
Variable rate debt \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	308,838	309,947
Mortgage notes payable \| Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable, net	0	313,812
Deferred financing costs, net	0	200
Mortgage notes payable \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 0	$ 317,031

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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No definition available.

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Amount, before allowance and fees, of loans and leases receivable. Excludes loans and leases covered under loss sharing agreements.

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Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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