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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 903,693	$ 843,624	$ 910,163	$ 1,073,733
Other comprehensive income	(27,403)	65,030	(33,978)	45,353
Ending Balance	873,013	912,889	873,013	912,889
Unrealized Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(28,759)		(43,667)
Other comprehensive loss before reclassifications	(7,088)		6,204
Amounts reclassified from accumulated other comprehensive income	1,566		3,182
Other comprehensive income	(5,522)		9,386
Ending Balance	(34,281)		(34,281)
Unrealized Gains and Losses on Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	63,068		84,551
Other comprehensive loss before reclassifications	(21,881)		(43,364)
Amounts reclassified from accumulated other comprehensive income	0		0
Other comprehensive income	(21,881)		(43,364)
Ending Balance	41,187		41,187
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	34,309	(6,278)	40,884	13,399
Other comprehensive loss before reclassifications	(28,969)		(37,160)
Amounts reclassified from accumulated other comprehensive income	1,566		3,182
Other comprehensive income	(27,403)		(33,978)
Ending Balance	$ 6,906	$ 58,752	$ 6,906	$ 58,752