Loans and Lease Finance Receivables and Allowance for Credit Losses - Summary of Loan, Including PCI Loans by Internal Risk Ratings (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	$ 8,904,910	$ 9,079,392
Commercial And Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	969,895	948,683
SBA Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	270,619	290,908
Total loans, at amortized cost	270,619	290,908
Commercial Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	2,433,252	2,485,110
SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	269,868	266,024
Total loans, at amortized cost	269,868	266,024
Dairy & Livestock and Agribusiness [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	412,891	433,564
Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	73,590	81,126
Total loans, at amortized cost	73,590	81,126
Consumer and Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	54,072	76,781
Total loans, at amortized cost	54,072	76,781
Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	8,520,770	8,788,580
Pass [Member] \| SBA Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	257,349	284,492
Pass [Member] \| SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	266,766	264,479
Pass [Member] \| Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	73,408	80,681
Pass [Member] \| Consumer and Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	53,038	74,640
Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	281,943	212,154
Special Mention [Member] \| SBA Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	9,303	4,679
Special Mention [Member] \| SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	2,578	943
Special Mention [Member] \| Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	182	262
Special Mention [Member] \| Consumer and Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	423	1,151
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	102,197	78,658
Substandard [Member] \| SBA Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	3,967	1,737
Substandard [Member] \| SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	524	602
Substandard [Member] \| Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost		183
Substandard [Member] \| Consumer and Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost	611	990
Doubtful & Loss [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost		0
Doubtful & Loss [Member] \| SBA Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost		0
Doubtful & Loss [Member] \| SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost		0
Doubtful & Loss [Member] \| Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost		0
Doubtful & Loss [Member] \| Consumer and Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, at amortized cost		$ 0