REAL ESTATE AND RELATED LEASE INTANGIBLES, NET - Additional Information (Details)					1 Months Ended	3 Months Ended			12 Months Ended
	Jan. 01, 2020 loans	May 01, 2019 USD ($)	Feb. 06, 2019 USD ($)	Jan. 10, 2019 USD ($)	Feb. 28, 2021 USD ($)	Dec. 31, 2020 USD ($)		Mar. 31, 2019 USD ($)	Dec. 31, 2021 USD ($) loan		Dec. 31, 2020 USD ($) loan		Dec. 31, 2019 USD ($)	Jun. 30, 2020 USD ($)
Business Acquisition [Line Items]
Real estate held for sale						$ 0	[1]		$ 25,179,000	[1]	$ 0	[1]	$ 0
Accumulated depreciation and amortization						(230,925,000)			(229,271,000)		(230,925,000)
Foreclosed properties held in real estate						106,800,000			97,300,000		106,800,000
Unbilled rent receivables						500,000			400,000		500,000
Unencumbered real estates						75,900,000			85,900,000		75,900,000
Real estate operating income									8,800,000		5,600,000		2,600,000
Impairment of real estate								$ 1,400,000	0		0		1,350,000
Proceeds from lease prepayments				$ 10,000,000
Mortgage loan and financing related to property sales			$ 6,600,000
Gain (loss) on extinguishment of debt			$ (1,100,000)			22,250,000			0		22,250,000		(1,070,000)
Real estate operating income		$ 3,900,000				100,248,000			101,564,000		100,248,000		106,366,000
Loss on sale of real estate		3,500,000
Depreciation and amortization		400,000				39,079,000			37,801,000		39,079,000		38,511,000
Loss on sale of real estate		$ 20,000
Realized (gain) loss on disposition of loan									(26,000)		98,000		2,250,000
Provision for (release of) loan loss reserves						18,275,000			(8,713,000)		$ 18,275,000		$ 2,600,000
Net earnings (loss)									0
Loans that previously had asset-specific reserves	3										4
Disposal Group, Held-for-sale, Not Discontinued Operations
Business Acquisition [Line Items]
Undepreciated real estate and lease intangibles									32,500,000
Accumulated depreciation and amortization									$ (7,400,000)
Accounting Standards Update 2016-13
Business Acquisition [Line Items]
Loans that previously had asset-specific reserves | loan									3
Wayne, NJ
Business Acquisition [Line Items]
Property book value								5,600,000
Accumulated depreciation and amortization								$ 2,700,000
Hotel
Business Acquisition [Line Items]
Real estate acquired through foreclosure, net basis														$ 3,800,000
Hotel | Miami, FL
Business Acquisition [Line Items]
Realized (gain) loss on disposition of loan					$ (25,800)
Real estate acquired through foreclosure, net basis					$ 45,100,000
Provision for (release of) loan loss reserves						1,200,000
Land
Business Acquisition [Line Items]
Undepreciated real estate and lease intangibles						220,511,000			$ 186,940,000		$ 220,511,000
Land | Disposal Group, Held-for-sale, Not Discontinued Operations
Business Acquisition [Line Items]
Undepreciated real estate and lease intangibles									900,000
Building
Business Acquisition [Line Items]
Undepreciated real estate and lease intangibles						$ 838,542,000			765,690,000		$ 838,542,000
Building | Disposal Group, Held-for-sale, Not Discontinued Operations
Business Acquisition [Line Items]
Undepreciated real estate and lease intangibles									27,400,000
In-place leases and other intangibles | Disposal Group, Held-for-sale, Not Discontinued Operations
Business Acquisition [Line Items]
Undepreciated real estate and lease intangibles									$ 4,300,000

[1] Includes amounts relating to consolidated variable interest entities. Refer to Note 2 and Note 10.