SECURITIES (Securities available for sale) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gains	$ 4,762	$ 401
Gross Unrealized Losses	(343,170)	(453,854)
Estimated Fair Value	880,341
Equity securities with a readily determinable fair value	22,117	21,056
Amortized Cost	4,395,743	5,100,344
Estimated Fair Value	4,057,335	4,646,891
Total debt securities
Debt Securities, Available-for-sale [Line Items]
Total debt securities	4,373,626	5,079,288
Gross Unrealized Gains	4,762	401
Gross Unrealized Losses	(343,170)	(453,854)
Estimated Fair Value	4,035,218	4,625,835
U.S. treasuries
Debt Securities, Available-for-sale [Line Items]
Total debt securities	7,999	32,459
Gross Unrealized Gains	12	0
Gross Unrealized Losses	(48)	(341)
Estimated Fair Value	7,963	32,118
U.S. agencies
Debt Securities, Available-for-sale [Line Items]
Total debt securities	11,540	14,724
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(100)	(194)
Estimated Fair Value	11,440	14,530
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Total debt securities	831,693	839,754
Gross Unrealized Gains	41	25
Gross Unrealized Losses	(91,110)	(98,534)
Estimated Fair Value	740,624	741,245
Mortgage-backed securities - agency
Debt Securities, Available-for-sale [Line Items]
Total debt securities	1,529,857	1,620,409
Gross Unrealized Gains	54	13
Gross Unrealized Losses	(184,934)	(226,793)
Estimated Fair Value	1,344,977	1,393,629
Mortgage-backed securities - non-agency
Debt Securities, Available-for-sale [Line Items]
Total debt securities	1,274,395	1,616,414
Gross Unrealized Gains	4,627	363
Gross Unrealized Losses	(42,326)	(87,649)
Estimated Fair Value	1,236,696	1,529,128
Commercial mortgage-backed securities - agency
Debt Securities, Available-for-sale [Line Items]
Total debt securities	71,504	76,076
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(8,971)	(11,288)
Estimated Fair Value	62,533	64,788
Commercial mortgage-backed securities - non-agency
Debt Securities, Available-for-sale [Line Items]
Total debt securities	394,298	526,974
Gross Unrealized Gains	28	0
Gross Unrealized Losses	(6,385)	(12,116)
Estimated Fair Value	387,941	514,858
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Total debt securities	129,896	232,140
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(7,166)	(14,770)
Estimated Fair Value	122,730	217,370
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Total debt securities	122,444	120,338
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2,130)	(2,169)
Estimated Fair Value	$ 120,314	$ 118,169