LOANS HELD FOR INVESTMENT - Corporation's Aging of Loans Held for Investment Portfolio (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Loans held for investment	$ 12,311,448	$ 12,185,483
Nonaccrual Loans with No ACL	11,662	6,953
Loans Past Due 90 days or more and Still Accruing	57,515	59,452
Financing Receivable, Nonaccrual	92,965	83,707
Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	12,027,302	11,891,511
30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	80,710	89,185
60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	52,956	61,628
Residential Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,801,587	2,821,726
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,701,932	2,721,490
Nonaccrual Loans with No ACL	1,700	1,742
Loans Past Due 90 days or more and Still Accruing	10,304	11,029
Financing Receivable, Nonaccrual	32,685	32,239
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,628,748	2,644,344
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	30,195	33,878
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	99,655	100,236
Nonaccrual Loans with No ACL	0	0
Loans Past Due 90 days or more and Still Accruing	28,265	29,312
Financing Receivable, Nonaccrual	0	0
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	69,170	68,332
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,220	2,592
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,230,995	3,174,232
Nonaccrual Loans with No ACL	1,644	1,687
Loans Past Due 90 days or more and Still Accruing	7,829	8,455
Financing Receivable, Nonaccrual	25,067	15,250
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,194,816	3,148,254
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,134	1,130
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	149	1,143
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,361,731	2,317,083
Nonaccrual Loans with No ACL	6,865	2,536
Loans Past Due 90 days or more and Still Accruing	939	1,108
Financing Receivable, Nonaccrual	11,976	12,205
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,347,395	2,303,753
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	708	17
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	713	0
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	237,288	214,777
Nonaccrual Loans with No ACL	971	972
Loans Past Due 90 days or more and Still Accruing	2,284	2,297
Financing Receivable, Nonaccrual	1,498	1,569
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	233,506	210,911
Commercial Portfolio Segment [Member] | Construction Loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Commercial Portfolio Segment [Member] | Construction Loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,679,847	3,657,665
Consumer Portfolio Segment [Member] | Auto loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	1,954,076	1,936,256
Nonaccrual Loans with No ACL	388	4
Loans Past Due 90 days or more and Still Accruing	0	0
Financing Receivable, Nonaccrual	15,132	15,568
Consumer Portfolio Segment [Member] | Auto loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	1,880,077	1,846,652
Consumer Portfolio Segment [Member] | Auto loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	49,811	60,283
Consumer Portfolio Segment [Member] | Auto loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	9,056	13,753
Consumer Portfolio Segment [Member] | Finance Leases [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	871,927	856,815
Nonaccrual Loans with No ACL	87	12
Loans Past Due 90 days or more and Still Accruing	0	0
Financing Receivable, Nonaccrual	2,744	3,287
Consumer Portfolio Segment [Member] | Finance Leases [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	852,320	837,881
Consumer Portfolio Segment [Member] | Finance Leases [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	14,312	13,786
Consumer Portfolio Segment [Member] | Finance Leases [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,551	1,861
Consumer Portfolio Segment [Member] | Personal Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	379,525	381,275
Nonaccrual Loans with No ACL	0	0
Loans Past Due 90 days or more and Still Accruing	0	0
Financing Receivable, Nonaccrual	2,030	1,841
Consumer Portfolio Segment [Member] | Personal Loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	368,984	370,746
Consumer Portfolio Segment [Member] | Personal Loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	5,624	5,873
Consumer Portfolio Segment [Member] | Personal Loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,887	2,815
Consumer Portfolio Segment [Member] | Credit Card Receivables [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	323,062	329,212
Nonaccrual Loans with No ACL	0	0
Loans Past Due 90 days or more and Still Accruing	7,894	7,251
Financing Receivable, Nonaccrual	0	0
Consumer Portfolio Segment [Member] | Credit Card Receivables [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	306,767	313,360
Consumer Portfolio Segment [Member] | Credit Card Receivables [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	4,760	5,012
Consumer Portfolio Segment [Member] | Credit Card Receivables [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,641	3,589
Consumer Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	151,257	154,107
Nonaccrual Loans with No ACL	7	0
Loans Past Due 90 days or more and Still Accruing	0	0
Financing Receivable, Nonaccrual	1,833	1,748
Consumer Portfolio Segment [Member] | Other Loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	145,519	147,278
Consumer Portfolio Segment [Member] | Other Loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,361	3,084
Consumer Portfolio Segment [Member] | Other Loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment	$ 1,544	$ 1,997