FAIR VALUE DISCLOSURES OF FINANCIAL ASSETS AND LIABILITIES - Schedule of Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	$ 4,093,060	$ 5,205,311
Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets	156,993	5,153
Liabilities measured at fair value on a recurring basis:
Other liabilities	173,622	23,291
Assets measured at fair value on a nonrecurring basis:
Total assets measured at fair value	4,250,053	5,210,464
Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	833	2,320
Total assets measured at fair value	69,938	126,187
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets	0	0
Liabilities measured at fair value on a recurring basis:
Other liabilities	0	0
Assets measured at fair value on a nonrecurring basis:
Total assets measured at fair value	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	0	0
Total assets measured at fair value	0	0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets	156,912	5,153
Liabilities measured at fair value on a recurring basis:
Other liabilities	156,520	3,039
Assets measured at fair value on a nonrecurring basis:
Total assets measured at fair value	4,249,972	5,210,464
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	0	0
Total assets measured at fair value	42,985	113,349
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets	81	0
Liabilities measured at fair value on a recurring basis:
Other liabilities	17,102	20,252
Assets measured at fair value on a nonrecurring basis:
Total assets measured at fair value	81	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	833	2,320
Total assets measured at fair value	26,953	12,838
Other investments | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other investments	26,120	10,518
Other investments | Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other investments	0	0
Other investments | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other investments	0	0
Other investments | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other investments	26,120	10,518
Loans held for sale | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Loans held for sale	42,985	113,349
Loans held for sale | Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Loans held for sale	0	0
Loans held for sale | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Loans held for sale	42,985	113,349
Loans held for sale | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Loans held for sale	0	0
Collateralized mortgage obligation (CMO)
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	506,380	575,766
Collateralized mortgage obligation (CMO) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	506,380	575,766
Collateralized mortgage obligation (CMO) | Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Collateralized mortgage obligation (CMO) | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	506,380	575,766
Collateralized mortgage obligation (CMO) | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Fannie Mae (FNMA) mortgage-backed securities (MBS)
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	3,250,258	4,245,684
Fannie Mae (FNMA) mortgage-backed securities (MBS) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	3,250,258	4,245,684
Fannie Mae (FNMA) mortgage-backed securities (MBS) | Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Fannie Mae (FNMA) mortgage-backed securities (MBS) | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	3,250,258	4,245,684
Fannie Mae (FNMA) mortgage-backed securities (MBS) | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Freddie Mac (FHLMC) MBS
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	121,999	145,528
Freddie Mac (FHLMC) MBS | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	121,999	145,528
Freddie Mac (FHLMC) MBS | Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Freddie Mac (FHLMC) MBS | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	121,999	145,528
Freddie Mac (FHLMC) MBS | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Ginnie Mae (GNMA) MBS
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	36,138	17,936
Ginnie Mae (GNMA) MBS | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	36,138	17,936
Ginnie Mae (GNMA) MBS | Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Ginnie Mae (GNMA) MBS | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	36,138	17,936
Ginnie Mae (GNMA) MBS | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Government-sponsored enterprises (GSE) agency notes
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	178,285	220,397
Government-sponsored enterprises (GSE) agency notes | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	178,285	220,397
Government-sponsored enterprises (GSE) agency notes | Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	0	0
Government-sponsored enterprises (GSE) agency notes | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	178,285	220,397
Government-sponsored enterprises (GSE) agency notes | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities, available for sale (amortized cost of $4,834,550 at December 31, 2022 and $5,249,882 at December 31, 2021)	$ 0	$ 0