CAPITAL RATIOS AND SHAREHOLDERS' EQUITY - Amounts Reclassified Out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Amounts reclassified out of each component of accumulated other comprehensive income
Non-interest income	$ 19,963	$ 21,406	$ 42,980	$ 60,640
Tax expense	68	(4,007)	18,194	(16,042)
Income/(loss) available to common shareholders	21,167	22,376	(548,339)	70,979
Amount Reclassified From Accumulated Other Comprehensive Income (loss)
Amounts reclassified out of each component of accumulated other comprehensive income
Income/(loss) available to common shareholders	4	4	4	7
Realized gains on AFS securities | Amount Reclassified From Accumulated Other Comprehensive Income (loss)
Amounts reclassified out of each component of accumulated other comprehensive income
Non-interest income	6	5	5	9
Tax expense	(2)	(1)	(1)	(2)
Income/(loss) available to common shareholders	$ 4	$ 4	$ 4	$ 7