DERIVATIVES (Gains (Losses) on All Derivatives) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Pay fixed-receive variable interest rate swaps | Interest expense on borrowings | Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	$ (7,497)	$ 13,842	$ (8,321)	$ 26,782
Pay variable receive-fixed interest rate swap | Interest income on loans | Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	26,079	(11,250)	22,924	(22,698)
Forward commitments to sell loans | Miscellaneous income, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	7,741	(819)	(3,090)	834
Interest rate lock commitments | Miscellaneous income, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	1,395	1,495	13,392	1,794
Mortgage servicing | Miscellaneous income, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	2,727	12,947	32,113	21,301
Customer-related derivatives | Miscellaneous income, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	23,739	(2,291)	8,120	(16,350)
Foreign exchange | Miscellaneous income, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	1,783	6,044	12,805	29,977
Interest rate swaps, caps, and options | Miscellaneous income, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	(1,028)	5,421	(10,686)	7,866
Other | Miscellaneous income, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized on derivatives	$ (4,149)	$ 843	$ (3,919)	$ (368)