USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT, Balance Sheet and Income Statement Location (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Balance sheet-related [Abstract]
Swap agreements in a gain position (an asset) related to borrowings		$ 24		$ 24		$ 7,720
Swap agreements in a loss position (a liability) related to borrowings		(62,003)		(62,003)		(26,061)
Interest rate swap agreements at fair value, net assets (liability)		(76,299)		(76,299)		(29,283)
Income statement-related [Abstract]
Amount of loss reclassified from Accumulated other comprehensive income related to the effective portion of active positions		5,826	$ 6,863	11,180	$ 13,311
Other Comprehensive Income (Loss) [Member]
Other comprehensive income related [Abstract]
Amount of gain (loss) recognized in Other comprehensive income (loss) (effective portion)		(22,145)	3,400	(54,272)	(14,991)
Interest Expense [Member]
Income statement-related [Abstract]
Amount of loss reclassified from Accumulated other comprehensive income related to the effective portion of active positions		(5,826)	(6,863)	(11,180)	(13,311)
Amount of gain (loss) recognized (ineffective portion)		(239)	3	(887)	(306)
Increase in interest expense and decrease in Net income as a result of the use of Derivatives	[1]	(6,065)	$ (6,860)	(12,067)	$ (13,617)
Other Assets [Member] | Interest Rate Swap Agreements [Member] | Secured Borrowings [Member]
Balance sheet-related [Abstract]
Swap agreements in a gain position (an asset) related to borrowings	[2]	24		24		7,720
Other Liabilities [Member]
Balance sheet-related [Abstract]
Related net interest payable	[3]	(14,320)		(14,320)		(10,942)
Other Liabilities [Member] | Interest Rate Swap Agreements [Member] | Secured Borrowings [Member]
Balance sheet-related [Abstract]
Swap agreements in a loss position (a liability) related to borrowings	[2]	(20,963)		(20,963)		(1,051)
Other Liabilities [Member] | Interest Rate Swap Agreements [Member] | Unsecured Borrowings [Member]
Balance sheet-related [Abstract]
Swap agreements in a loss position (a liability) related to borrowings	[2]	$ (41,040)		$ (41,040)		$ (25,010)

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

[2] 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 net 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 $19.9 million at June 30, 2016.

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