Fair Value Disclosures - Schedule of Estimated Fair Values and Carrying Values of All Financial Instruments (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
CASH AND DUE FROM BANKS	$ 293,286,000	$ 205,053,000
INTEREST-BEARING DEMAND DEPOSITS IN BANKS	37,392,000	323,535,000
Securities available-for-sale, at fair value	5,474,359,000	6,573,179,000
Loans held-for-investment, net of allowance for credit losses	6,366,034,000	5,325,507,000
Loans held-for-sale	11,965,000	37,810,000
Deposits with stated maturities	524,666,000
BORROWINGS	642,507,000	671,152,000
IRLCs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Asset Derivative Fair Value	400,000	1,279,000
Liability Derivative Fair Value	0	0
Forward Mortgage-Backed Securities Trades [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Asset Derivative Fair Value	85,000	0
Liability Derivative Fair Value	0	147,000
Level 1 Inputs [Member] | Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
CASH AND DUE FROM BANKS	293,286,000	205,053,000
INTEREST-BEARING DEMAND DEPOSITS IN BANKS	37,392,000	323,535,000
Deposits with no stated maturities	10,480,841,000	10,105,073,000
Level 1 Inputs [Member] | Estimated Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
CASH AND DUE FROM BANKS	293,286,000	205,053,000
INTEREST-BEARING DEMAND DEPOSITS IN BANKS	37,392,000	323,535,000
Deposits with no stated maturities	10,480,841,000	10,105,073,000
Levels 1 and 2 Inputs [Member] | Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Securities available-for-sale, at fair value	5,474,359,000	6,573,179,000
Levels 1 and 2 Inputs [Member] | Estimated Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Securities available-for-sale, at fair value	5,474,359,000	6,573,179,000
Level 3 Inputs [Member] | Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans held-for-investment, net of allowance for credit losses	6,366,034,000	5,325,507,000
Level 3 Inputs [Member] | Estimated Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans held-for-investment, net of allowance for credit losses	6,372,859,000	5,335,791,000
Level 2 Inputs [Member] | Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans held-for-sale	11,965,000	37,810,000
Accrued interest receivable	58,162,000	57,169,000
Deposits with stated maturities	524,666,000	461,415,000
BORROWINGS	642,507,000	671,152,000
Accrued interest payable	1,121,000	221,000
Level 2 Inputs [Member] | Carrying Value [Member] | IRLCs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Asset Derivative Fair Value	400,000	1,279,000
Level 2 Inputs [Member] | Carrying Value [Member] | Forward Mortgage-Backed Securities Trades [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liability Derivative Fair Value	85,000	(147,000)
Level 2 Inputs [Member] | Estimated Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans held-for-sale	11,965,000	37,844,000
Accrued interest receivable	58,162,000	57,169,000
Deposits with stated maturities	518,811,000	462,312,000
BORROWINGS	642,507,000	671,152,000
Accrued interest payable	1,121,000	221,000
Level 2 Inputs [Member] | Estimated Fair Value [Member] | IRLCs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Asset Derivative Fair Value	400,000	1,279,000
Level 2 Inputs [Member] | Estimated Fair Value [Member] | Forward Mortgage-Backed Securities Trades [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liability Derivative Fair Value	$ 85,000	$ (147,000)