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	Jun. 30, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	$ 8,358,501	$ 8,536,432
Construction	17,658	16,082
Total loans, at amortized cost	8,358,501	8,536,432
Less: Allowance for credit losses	(78,003)	(80,122)
Net loans and lease finance receivables	8,280,498	8,456,310
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	6,517,415	6,507,452
SBA [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	271,735	273,013
SBA - Paycheck Protection Program (PPP) [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	85	774
Total loans, at amortized cost	85	774
Commercial And Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	912,427	925,178
Dairy And Livestock And Agribusiness [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	233,772	419,904
Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	63,652	66,114
Total loans, at amortized cost	63,652	66,114
SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	288,435	269,172
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	$ 53,322	$ 58,743