USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT- Changes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	$ 136,095
Other comprehensive income (loss) before reclassifications	(19,644)
Amounts reclassified from accumulated other comprehensive income	5,354
Other comprehensive income (loss)	(14,290)	$ (5,836)
Ending Balance	121,805
Gains and Losses on Cash Flow Hedges [Member]
Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(18,434)
Other comprehensive income (loss) before reclassifications	(32,127)
Amounts reclassified from accumulated other comprehensive income	5,354
Other comprehensive income (loss)	(26,773)
Ending Balance	(45,207)
Unrealized Gains and Losses on Available-for-sale Securities [Member]
Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	154,529
Other comprehensive income (loss) before reclassifications	12,483
Amounts reclassified from accumulated other comprehensive income	0
Other comprehensive income (loss)	12,483
Ending Balance	$ 167,012