Loans and Lease Finance Receivables and Allowance for Credit Losses - Summary of Components of Loans and Lease Finance Receivables, Including PCI Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	$ 12,122,015	$ 8,699,193
Total loans, at amortized cost	12,122,015	8,699,193
Less: Allowance for credit losses	(125,641)	(77,161)
Net loans and lease finance receivables	11,996,374	8,622,032
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	9,032,741	6,574,395
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	229,046	37,812
Construction	229,046	37,812
SBA Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	470,293	282,401
Commercial And Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	1,439,834	973,631
Dairy And Livestock And Agribusiness [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	341,801	431,577
Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	53,800	59,542
Total loans, at amortized cost	53,800	59,542
SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	338,394	281,766
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	$ 216,106	$ 58,069