FAIR VALUE DISCLOSURES OF FINANCIAL ASSETS AND LIABILITIES - Schedule of Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	$ 3,734,229	$ 3,846,537
Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets, fair value	168,554	153,647
Liabilities measured at fair value on a recurring basis:
Other liabilities	169,669	151,642
Assets measured at fair value on a nonrecurring basis:
Total assets measured at fair value	3,902,783	4,000,184
Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	1,210	1,569
Total assets measured at fair value	42,782	46,043
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, fair value	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, fair value	168,510	153,569
Liabilities measured at fair value on a recurring basis:
Other liabilities	156,243	137,616
Assets measured at fair value on a nonrecurring basis:
Total assets measured at fair value	3,902,739	4,000,106
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	26,858	29,268
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets, fair value	44	78
Liabilities measured at fair value on a recurring basis:
Other liabilities	13,426	14,026
Assets measured at fair value on a nonrecurring basis:
Total assets measured at fair value	44	78
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	1,210	1,569
Total assets measured at fair value	15,924	16,775
Other investments | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other investments	14,714	15,206
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	14,714	15,206
Loans held for sale | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Loans held for sale	26,858	29,268
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	26,858	29,268
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	451,891	464,619
Collateralized mortgage obligation (CMO) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	451,891	464,619
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	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	451,891	464,619
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	0	0
Fannie Mae (FNMA) mortgage-backed securities (MBS)
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	2,947,349	3,042,350
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	2,947,349	3,042,350
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	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	2,947,349	3,042,350
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	0	0
Freddie Mac (FHLMC) MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	111,751	115,532
Freddie Mac (FHLMC) MBS | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	111,751	115,532
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	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	111,751	115,532
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	0	0
Ginnie Mae (GNMA) MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	43,940	43,340
Ginnie Mae (GNMA) MBS | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	43,940	43,340
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	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	43,940	43,340
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	0	0
Government-sponsored enterprises (GSE) agency notes
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	179,298	180,696
Government-sponsored enterprises (GSE) agency notes | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	179,298	180,696
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	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	179,298	180,696
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	$ 0	$ 0