SECURITIES - Summary of Available-For-Sale Securities With Unrealized and Unrecognized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Fair value, less than 12 months	$ 36,440	$ 475,479
Fair value, 12 months or longer	1,089,053	752,306
Fair value, total	1,125,493	1,227,785
Unrealized losses, less than 12 months	3,225	43,854
Unrealized losses, 12 months or longer	181,919	118,054
Unrealized losses, total	185,144	161,908
Fair value, held-to-maturity, less than 12 months	120,974	530,503
Fair value, held-to-maturity, 12 months or longer	450,059	15,303
Fair value, held-to-maturity, total	571,033	545,806
Unrealized losses, held-to-maturity, less than 12 months	10,973	53,803
Unrealized losses, held-to-maturity, 12 months or longer	65,055	116
Unrealized losses, held-to-maturity, total	76,028	53,919
U.S. Treasury
Debt and Equity Securities, FV-NI [Line Items]
Fair value, less than 12 months	0	4,563
Fair value, 12 months or longer	124,694	119,292
Fair value, total	124,694	123,855
Unrealized losses, less than 12 months	0	419
Unrealized losses, 12 months or longer	10,954	11,479
Unrealized losses, total	10,954	11,898
Fair value, held-to-maturity, less than 12 months	0	104,457
Fair value, held-to-maturity, 12 months or longer	85,431	0
Fair value, held-to-maturity, total	85,431	104,457
Unrealized losses, held-to-maturity, less than 12 months	0	5,175
Unrealized losses, held-to-maturity, 12 months or longer	4,256	0
Unrealized losses, held-to-maturity, total	4,256	5,175
Obligations of U.S. government agencies and sponsored entities
Debt and Equity Securities, FV-NI [Line Items]
Fair value, less than 12 months	187	34,254
Fair value, 12 months or longer	124,848	109,431
Fair value, total	125,035	143,685
Unrealized losses, less than 12 months	0	2,293
Unrealized losses, 12 months or longer	21,984	16,395
Unrealized losses, total	21,984	18,688
Fair value, held-to-maturity, less than 12 months	708	31,636
Fair value, held-to-maturity, 12 months or longer	30,166	0
Fair value, held-to-maturity, total	30,874	31,636
Unrealized losses, held-to-maturity, less than 12 months	36	2,153
Unrealized losses, held-to-maturity, 12 months or longer	2,745	0
Unrealized losses, held-to-maturity, total	2,781	2,153
Tax-exempt and taxable obligations of states and municipal subdivisions
Debt and Equity Securities, FV-NI [Line Items]
Fair value, less than 12 months	35,198	275,202
Fair value, 12 months or longer	373,596	159,508
Fair value, total	408,794	434,710
Unrealized losses, less than 12 months	3,215	31,152
Unrealized losses, 12 months or longer	71,609	30,779
Unrealized losses, total	74,824	61,931
Fair value, held-to-maturity, less than 12 months	119,396	127,628
Fair value, held-to-maturity, 12 months or longer	87,466	15,303
Fair value, held-to-maturity, total	206,862	142,931
Unrealized losses, held-to-maturity, less than 12 months	10,885	13,583
Unrealized losses, held-to-maturity, 12 months or longer	17,403	116
Unrealized losses, held-to-maturity, total	28,288	13,699
Mortgage-backed securities - residential
Debt and Equity Securities, FV-NI [Line Items]
Fair value, less than 12 months	749	76,125
Fair value, 12 months or longer	259,613	222,274
Fair value, total	260,362	298,399
Unrealized losses, less than 12 months	10	4,970
Unrealized losses, 12 months or longer	46,904	37,071
Unrealized losses, total	46,914	42,041
Fair value, held-to-maturity, less than 12 months	0	138,639
Fair value, held-to-maturity, 12 months or longer	123,020	0
Fair value, held-to-maturity, total	123,020	138,639
Unrealized losses, held-to-maturity, less than 12 months	0	17,479
Unrealized losses, held-to-maturity, 12 months or longer	21,971	0
Unrealized losses, held-to-maturity, total	21,971	17,479
Mortgage-backed securities - commercial
Debt and Equity Securities, FV-NI [Line Items]
Fair value, less than 12 months	306	50,193
Fair value, 12 months or longer	169,023	136,062
Fair value, total	169,329	186,255
Unrealized losses, less than 12 months	0	3,025
Unrealized losses, 12 months or longer	26,114	21,338
Unrealized losses, total	26,114	24,363
Fair value, held-to-maturity, less than 12 months	870	119,758
Fair value, held-to-maturity, 12 months or longer	115,680	0
Fair value, held-to-maturity, total	116,550	119,758
Unrealized losses, held-to-maturity, less than 12 months	52	13,798
Unrealized losses, held-to-maturity, 12 months or longer	16,976	0
Unrealized losses, held-to-maturity, total	17,028	13,798
Corporate obligations
Debt and Equity Securities, FV-NI [Line Items]
Fair value, less than 12 months	0	35,142
Fair value, 12 months or longer	37,279	5,739
Fair value, total	37,279	40,881
Unrealized losses, less than 12 months	0	1,995
Unrealized losses, 12 months or longer	4,354	992
Unrealized losses, total	4,354	2,987
Fair value, held-to-maturity, less than 12 months	0	8,385
Fair value, held-to-maturity, 12 months or longer	8,296	0
Fair value, held-to-maturity, total	8,296	8,385
Unrealized losses, held-to-maturity, less than 12 months	0	1,615
Unrealized losses, held-to-maturity, 12 months or longer	1,704	0
Unrealized losses, held-to-maturity, total	$ 1,704	$ 1,615