Fair Value Measurements - Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	$ 10,748,961	$ 3,955,804
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account	117,847	49,545
Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account		200
U.S. Treasury and Federal Agencies [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	7,670,960	678,690
Commercial Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	574,299
Residential Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	2,330,118	3,155,312
Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	173,584	121,802
Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account	117,847	49,745
Debt Securities, Available-for-Sale	10,748,961	3,955,804
Equity Securities, FV-NI, Current	151,458	77,640
Real estate loans held for sale	162,393	899,282
Other assets	435,969	442,453
Total assets	11,616,628	5,424,924
Other liabilities	1,355,326	93,843
Total liabilities	1,355,326	93,843
Fair Value Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account	117,847	49,545
Equity Securities, FV-NI, Current	145,289	68,850
Total assets	263,136	118,395
Fair Value Measurements, Recurring [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account		200
Debt Securities, Available-for-Sale	10,748,961	3,955,804
Equity Securities, FV-NI, Current	6,169	8,790
Real estate loans held for sale	162,393	899,282
Other assets	435,517	430,725
Total assets	11,353,040	5,294,801
Other liabilities	1,309,301	88,555
Total liabilities	1,309,301	88,555
Fair Value Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	452	11,728
Total assets	452	11,728
Other liabilities	46,025	5,288
Total liabilities	46,025	5,288
Fair Value Measurements, Recurring [Member] | U.S. Treasury and Federal Agencies [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	7,670,960	678,690
Fair Value Measurements, Recurring [Member] | U.S. Treasury and Federal Agencies [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	7,670,960	678,690
Fair Value Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	574,299
Fair Value Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	574,299
Fair Value Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	2,330,118	3,155,312
Fair Value Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	2,330,118	3,155,312
Fair Value Measurements, Recurring [Member] | Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	173,584	121,802
Fair Value Measurements, Recurring [Member] | Other Debt Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	$ 173,584	$ 121,802