SECURED FINANCING - Mortgage Loans Payable (Details) - Commercial Mortgage Loans - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Mortgage Carrying Value	$ 484,762,000	$ 485,005,000
Mortgage Principal	489,820,000	490,631,000
Joint Ventures
Debt Instrument [Line Items]
Mortgage Carrying Value	316,597,000	316,566,000
Mortgage Principal	$ 318,497,000	$ 318,562,000
Joint Ventures \| Minimum
Debt Instrument [Line Items]
Interest Rate	4.03%	4.03%
Joint Ventures \| Maximum
Debt Instrument [Line Items]
Interest Rate	4.96%	4.96%
Joint Ventures \| LIBOR
Debt Instrument [Line Items]
Mortgage Carrying Value	$ 16,471,000	$ 16,029,000
Mortgage Principal	$ 16,325,000	$ 16,325,000
Variable interest rate	2.15%	2.15%
Virginia
Debt Instrument [Line Items]
Mortgage Carrying Value	$ 82,461,000	$ 82,940,000
Mortgage Principal	$ 84,206,000	$ 84,702,000
Virginia \| Minimum
Debt Instrument [Line Items]
Interest Rate	2.34%	2.34%
Virginia \| Maximum
Debt Instrument [Line Items]
Interest Rate	4.55%	4.55%
Texas
Debt Instrument [Line Items]
Mortgage Carrying Value	$ 31,535,000	$ 31,667,000
Mortgage Principal	$ 33,023,000	$ 33,167,000
Interest Rate	3.28%	3.28%
Utah
Debt Instrument [Line Items]
Mortgage Carrying Value	$ 7,051,000	$ 7,077,000
Mortgage Principal	$ 7,069,000	$ 7,096,000
Interest Rate	3.69%	3.69%
Utah \| LIBOR
Debt Instrument [Line Items]
Mortgage Carrying Value	$ 9,706,000	$ 9,706,000
Mortgage Principal	$ 9,706,000	$ 9,706,000
Variable interest rate	2.75%	3.50%
Minnesota
Debt Instrument [Line Items]
Mortgage Carrying Value	$ 13,193,000	$ 13,243,000
Mortgage Principal	$ 13,226,000	$ 13,276,000
Interest Rate	3.69%	3.69%
Wisconsin
Debt Instrument [Line Items]
Mortgage Carrying Value	$ 7,748,000	$ 7,777,000
Mortgage Principal	$ 7,768,000	$ 7,797,000
Interest Rate	3.69%	3.69%

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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-Name Accounting Standards Codification
-Topic 942
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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