INVESTMENTS - Gross Unrealized Losses and Fair Value by Length of Time of Available-For-Sale Securities (Detail) $ in Thousands	Dec. 31, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Number of Securities | security	454	464
Fair Value
Less Than 12 Months	$ 26,893	$ 779,965
12 Months or More	1,050,289	400,181
Total	1,077,182	1,180,146
Unrealized Losses
Less Than 12 Months	190	79,408
12 Months or More	118,130	72,974
Total	$ 118,320	$ 152,382
U.S. treasuries and government agencies
Debt Securities, Available-for-sale [Line Items]
Number of Securities | security	10	10
Fair Value
Less Than 12 Months	$ 0	$ 53,139
12 Months or More	96,927	40,483
Total	96,927	93,622
Unrealized Losses
Less Than 12 Months	0	3,653
12 Months or More	4,751	3,651
Total	$ 4,751	$ 7,304
State and municipal
Debt Securities, Available-for-sale [Line Items]
Number of Securities | security	123	130
Fair Value
Less Than 12 Months	$ 4,162	$ 200,439
12 Months or More	262,081	62,482
Total	266,243	262,921
Unrealized Losses
Less Than 12 Months	84	30,803
12 Months or More	43,208	25,723
Total	$ 43,292	$ 56,526
Mortgage-backed and asset-backed
Debt Securities, Available-for-sale [Line Items]
Number of Securities | security	321	324
Fair Value
Less Than 12 Months	$ 22,731	$ 526,387
12 Months or More	691,281	297,216
Total	714,012	823,603
Unrealized Losses
Less Than 12 Months	106	44,952
12 Months or More	70,171	43,600
Total	$ 70,277	$ 88,552