INVESTMENT IN REAL ESTATE PROPERTIES - Net Investment in Sales-Type Lease Narrative (Details) - Skilled nursing transitional care facility $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) property	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) property	Jun. 30, 2020 USD ($)
Real Estate Properties [Line Items]
Net investment in sales type lease	$ 25,100		$ 25,100
Properties in sales-type | property	1		1
Total rental payments	$ 4,000		$ 4,000
Estimated purchase price	25,600		25,600
Unearned lease income			4,200
Allowance for credit losses related to sales-type lease	300		300
Lease income	600	$ 700	1,200	$ 1,300
Reduction in the allowance for credit losses related to sales-type lease	(21)	$ 21	(100)	$ 37
Future minimum lease payments contractually due under the direct financing lease for the remainder of this year	1,200		1,200
Future minimum lease payments contractually due under the direct financing lease due for next year	2,400		2,400
Future minimum lease payments contractually due under the direct financing lease due for year two	$ 800		800
Sales-Type Lease
Real Estate Properties [Line Items]
Aggregate net gain (loss) on sale of real estate			$ 1,000