SHAREHOLDERS’ EQUITY AND COMPENSATION PLANS - Pre-tax and After-tax Changes in the Components of 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
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, after Tax [Abstract]
Change in unrealized gain on available-for-sale debt securities, before tax	$ 3,795	$ 14,587	$ (10,746)	$ 28,616
Change in unrealized gain on available-for-sale debt securities, tax	945	3,603	(2,676)	7,068
Change in unrealized gain on available-for-sale debt securities, after tax	2,850	10,984	(8,070)	21,548
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract]
Reclassification adjustment for realized (gain) loss on sale of available-for-sale debt securities, before tax			0	(4)
Reclassification adjustment for realized (gain) loss on sale of available-for-sale debt securities, tax			0	(1)
Reclassification adjustment for realized (gain) loss on sale of available-for-sale debt securities, after tax	0	0	0	3
Other Comprehensive Loss, Held-to-maturity Security, OTTI, after Tax and Adjustments [Abstract]
Reclassification of (gain) loss on held-to-maturity securities, before tax	(1,115)	(437)	(2,644)	(644)
Reclassification of (gain) loss on held-to-maturity securities, tax	(278)	(108)	(658)	(159)
Reclassification of (gain) loss on held-to-maturity securities, after tax	(837)	(329)	(1,986)	(485)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent [Abstract]
Change in unrealized loss on cash flow hedges arising during the period, before tax	(273)	(1,563)	855	(8,442)
Change in unrealized loss on cash flow hedges arising during the period, tax	(68)	(386)	213	(2,085)
Change in unrealized loss on cash flow hedges arising during the period, after tax	(205)	(1,177)	642	(6,357)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Reclassification of loss on cash flow hedges, before tax	382	311	754	474
Reclassification of loss on cash flow hedges, tax	95	77	188	117
Reclassification of loss on cash flow hedges, after tax	(287)	(234)	(566)	(357)
OCI, Net of Tax [Abstract]
Total other comprehensive income, before tax	2,789	12,898	(11,781)	20,000
Total other comprehensive income, tax	694	3,186	(2,933)	4,940
Total other comprehensive income (loss), after-tax	$ 2,095	$ 9,712	$ (8,848)	$ 15,060