USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT- Balance Sheet and Income Statement Location (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Balance sheet-related [Abstract]
Interest rate swap agreements at fair value, net assets (liability)		$ (29,283)	$ (34,893)
Income statement-related [Abstract]
Amount of loss reclassified from Accumulated other comprehensive income related to the effective portion of active positions		28,550	22,055	$ 16,914
Other Comprehensive Income (Loss) [Member]
Other comprehensive income related [Abstract]
Amount of gain (loss) recognized in Other comprehensive income (loss) (effective portion)		(21,675)	(41,059)	9,320
Interest Expense [Member]
Income statement-related [Abstract]
Amount of loss reclassified from Accumulated other comprehensive income related to the effective portion of active positions		(28,550)	(22,055)	(16,914)
Amount of gain (loss) recognized (ineffective portion)		(924)	(473)	24
Increase in interest expense and decrease in Net income as a result of the use of Derivatives	[1]	(29,474)	(22,528)	$ (16,890)
Other Liabilities [Member]
Balance sheet-related [Abstract]
Related net interest payable	[2]	(10,942)	(9,516)
Secured Borrowings [Member] | Other Assets [Member]
Balance sheet-related [Abstract]
Interest rate swap agreements in a gain position (an asset)	[3]	7,720	1,657
Secured Borrowings [Member] | Other Liabilities [Member]
Balance sheet-related [Abstract]
Interest rate swap agreements in a loss position (a liability)	[3]	(1,051)	(6,332)
Unsecured Borrowings [Member] | Other Liabilities [Member]
Balance sheet-related [Abstract]
Interest rate swap agreements in a loss position (a liability)	[3]	$ (25,010)	$ (20,702)

[1] Included in "Interest expense: Secured borrowings" on the face of the Statements of Income.

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

[3] 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 losses scheduled to be recognized in the Statements of Income over the next twelve months primarily in the form of fixed-rate swap payments in excess of current market rates totaled $5.6 million at December 31, 2015.