INVESTMENT SECURITIES - Investment securities in a continuous unrealized loss position (Details) $ in Thousands	Dec. 31, 2022 USD ($) position	Dec. 31, 2021 USD ($) position
Number of positions
Less than 12 months | position	1,149	240
12 months or longer | position	430	66
Total | position	1,579	306
Fair Value
Less than 12 months	$ 1,955,294	$ 1,395,578
12 months or longer	2,106,692	967,788
Total	4,061,986	2,363,366
Gross Unrealized Losses
Less than 12 months	188,107	17,505
12 months or longer	336,081	93,774
Total	524,188	111,279
Available-for-sale, allowance for credit losses	$ 0	$ 0
Number of positions
Less than 12 Months | position	23
12 Months or Longer | position	0
Total | position	23
Fair Value
Less than 12 Months	$ 1,034,795
12 Months or Longer	0
Total	1,034,795
Gross Unrealized Losses
Less than 12 Months	44,900
12 Months or Longer	0
Total	$ 44,900
U.S. Treasury and agency securities
Number of positions
Less than 12 months | position	41	47
12 months or longer | position	61	13
Total | position	102	60
Fair Value
Less than 12 months	$ 1,384,075	$ 1,224,101
12 months or longer	1,859,462	900,462
Total	3,243,537	2,124,563
Gross Unrealized Losses
Less than 12 months	132,511	14,873
12 months or longer	284,498	91,184
Total	$ 417,009	$ 106,057
Number of positions
Less than 12 Months | position	23
12 Months or Longer | position	0
Total | position	23
Fair Value
Less than 12 Months	$ 1,034,795
12 Months or Longer	0
Total	1,034,795
Gross Unrealized Losses
Less than 12 Months	44,900
12 Months or Longer	0
Total	$ 44,900
Obligations of state and political subdivisions
Number of positions
Less than 12 months | position	582	27
12 months or longer | position	76	0
Total | position	658	27
Fair Value
Less than 12 months	$ 370,524	$ 23,966
12 months or longer	47,923	0
Total	418,447	23,966
Gross Unrealized Losses
Less than 12 months	35,488	56
12 months or longer	9,839	0
Total	$ 45,327	$ 56
Government agency mortgage-backed securities
Number of positions
Less than 12 months | position	497	147
12 months or longer | position	274	52
Total | position	771	199
Fair Value
Less than 12 months	$ 190,727	$ 139,442
12 months or longer	189,919	67,273
Total	380,646	206,715
Gross Unrealized Losses
Less than 12 months	19,508	2,475
12 months or longer	40,606	2,590
Total	$ 60,114	$ 5,065
Corporate debt securities
Number of positions
Less than 12 months | position	0	1
12 months or longer | position	2	0
Total | position	2	1
Fair Value
Less than 12 months	$ 0	$ 4,923
12 months or longer	7,114	0
Total	7,114	4,923
Gross Unrealized Losses
Less than 12 months	0	77
12 months or longer	886	0
Total	$ 886	$ 77
Government agency collateralized mortgage obligations
Number of positions
Less than 12 months | position	29	18
12 months or longer | position	17	1
Total | position	46	19
Fair Value
Less than 12 months	$ 9,968	$ 3,146
12 months or longer	2,274	53
Total	12,242	3,199
Gross Unrealized Losses
Less than 12 months	600	24
12 months or longer	252	0
Total	$ 852	$ 24