USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME (LOSS) BY COMPONENT - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 910,163	$ 1,073,733
Other comprehensive income	(6,575)	(19,677)
Ending Balance	903,693	843,624
Unrealized Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(43,667)
Other comprehensive income (loss) before reclassifications	13,292
Amounts reclassified from accumulated other comprehensive income (loss)	1,616
Other comprehensive income	14,908
Ending Balance	(28,759)
Unrealized Gains and Losses on Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	84,551
Other comprehensive income (loss) before reclassifications	(21,483)
Amounts reclassified from accumulated other comprehensive income (loss)	0
Other comprehensive income	(21,483)
Ending Balance	63,068
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	40,884	13,399
Other comprehensive income (loss) before reclassifications	(8,191)
Amounts reclassified from accumulated other comprehensive income (loss)	1,616
Other comprehensive income	(6,575)
Ending Balance	$ 34,309	$ (6,278)