USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Components of Income Statement and Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income statement-related [Abstract]
Amount of gain (loss) reclassified from Accumulated other comprehensive income		$ (9,971)	$ (655)	$ (14,614)	$ 1,006
Other comprehensive income (loss)-related [Abstract]
Amount of gain recognized in Other comprehensive income		7,873	(6,487)	38,805	1,609
Interest Expense [Member]
Income statement-related [Abstract]
Decrease (increase) in interest expense and increase(decrease) in Net income as a result of the use of Derivatives		9,971	(453)	14,614	(2,507)
Interest Expense [Member] | Secured Borrowings [Member]
Income statement-related [Abstract]
Amount of gain (loss) reclassified from Accumulated other comprehensive income		10,445	1,387	15,692	500
Amount of loss recognized in income			(1,108)		(1,501)
Decrease (increase) in interest expense and increase(decrease) in Net income as a result of the use of Derivatives	[1]	10,445	279	15,692	(1,001)
Interest Expense [Member] | Unsecured Borrowings [Member]
Income statement-related [Abstract]
Amount of gain (loss) reclassified from Accumulated other comprehensive income	[2]	$ (474)	$ (732)	$ (1,078)	$ (1,506)

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

[2] Included in “Interest expense: Unsecured borrowings” on the face of the Statements of Income