USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT, Changes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ 1,298,324
Other comprehensive income (loss) before reclassifications	$ (6,597)		(31,469)
Amounts reclassified from accumulated other comprehensive income	4,927		16,107
Other comprehensive income (loss)	(1,670)	$ (25,182)	(15,362)	$ (39,502)
Ending Balance	1,270,110		1,270,110
Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	122,403		136,095
Ending Balance	120,733		120,733
Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(61,526)		(18,434)
Other comprehensive income (loss) before reclassifications	12,558		(41,714)
Amounts reclassified from accumulated other comprehensive income	4,927		16,107
Other comprehensive income (loss)	17,485		(25,607)
Ending Balance	(44,041)		(44,041)
Unrealized Gains and Losses on Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	183,929		154,529
Other comprehensive income (loss) before reclassifications	(19,155)		10,245
Amounts reclassified from accumulated other comprehensive income	0		0
Other comprehensive income (loss)	(19,155)		10,245
Ending Balance	$ 164,774		$ 164,774