REVENUE RECOGNITION - Timing of Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues
Revenue from contract with customer, including assessed tax	$ 1,248	$ 7	$ 3,141	$ 88
Over Lease Term	11,519
Total Revenues	14,283	13,010	28,995	25,848
Asset/Good Transferred at a Point in Time
Revenues
Revenue from contract with customer, including assessed tax	1,248	7	3,141	88
Services Transferred Over Time
Revenues
Revenue from contract with customer, including assessed tax	807	859	1,509	1,648
Income Properties
Revenues
Over Lease Term	11,519	11,309	22,935	22,225
Total Revenues	11,574	11,473	23,023	22,476
Income Properties | Services Transferred Over Time
Revenues
Revenue from contract with customer, including assessed tax	55	164	88	251
Management Fee Income
Revenues
Total Revenues	752	695	1,421	1,397
Management Fee Income | Services Transferred Over Time
Revenues
Revenue from contract with customer, including assessed tax	752	695	1,421	1,397
Interest Income from Commercial Loan and Master Lease Investments
Revenues
Commercial Loan Investment Related Revenue	709	835	1,410	1,887
Total Revenues	709	835	1,410	1,887
Real Estate Operations
Revenues
Total Revenues	1,248	7	3,141	88
Real Estate Operations | Asset/Good Transferred at a Point in Time
Revenues
Revenue from contract with customer, including assessed tax	$ 1,248	$ 7	$ 3,141	$ 88