USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Components of Balance Sheet (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Balance sheet-related [Abstract]
Swap agreements in a loss position (a liability) related to borrowings		$ (13,012)	$ (23,772)
Interest rate swap agreements at fair value, net assets (liability)		(13,928)	(24,256)
Interest Rate Swap Agreements at Fair Value [Member] | Unsecured Borrowings [Member]
Balance sheet-related [Abstract]
Swap agreements in a loss position (a liability) related to borrowings	[1]	(13,012)	(23,772)
Accounts Payable and Accrued Liabilities [Member]
Balance sheet-related [Abstract]
Related net interest payable	[2]	$ (916)	$ (484)

[1] The fair value of Derivatives with unrealized gains are aggregated and recorded as an asset on the face of the Balance Sheets separately from the fair value of Derivatives with unrealized losses that are recorded as a liability. The amount of unrealized gains, net of unrealized losses, scheduled to be recognized in the Statements of Income over the next twelve months primarily in the form of current market rates in excess of fixed-rate swap payments totaled $37.0 million at September 30, 2018.

[2] Included in “Accounts payable and accrued expenses” on the face of the Balance Sheets.