SENIOR NOTES PAYABLE AND OTHER DEBT - Mortgages (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt instruments
Unamortized fair value adjustment	$ 17,975	$ 20,056
Mortgages
Debt instruments
Mortgage loans and other	$ 1,943,909	$ 1,996,969

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.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant