LOANS RECEIVABLE AND OTHER INVESTMENTS - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal balance	$ 62,676,000		$ 62,676,000		$ 65,320,000
Book value	54,628,000		54,628,000		58,899,000
Increase (decrease) in the allowance for loan losses	0	$ (100,000)	1,800,000	$ 700,000
Allowance for loan losses	$ 4,269,000		$ 4,269,000		$ 2,458,000
Nonperforming Financial Instruments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans receivable on nonaccrual status | loan	3		3		2
Book value of loans receivable on nonaccrual status	$ 0		$ 0		$ 0
Portfolio-Based Loans Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses					$ 2,500,000
Receivables Acquired with Deteriorated Credit Quality
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans receivable considered to be impaired | loan	4		4		4
Principal balance	$ 1,900,000		$ 1,900,000		$ 2,100,000
Book value	$ 300,000		$ 300,000		$ 500,000