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, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	$ 9,073,571
Total loans	9,079,392	$ 7,887,713
Commercial And Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	948,683	813,063
SBA [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	290,908	288,600
Total loans	290,908	288,600
Commercial Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	2,482,471
Total loans	2,485,110	2,131,800
SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	266,024	240,654
Total loans	266,024	240,654
Dairy & Livestock and Agribusiness [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	433,564	386,219
Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	81,126	45,933
Total loans	81,126	45,933
Consumer and other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	76,781	74,665
Total loans	76,781	74,665
Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	8,788,580	7,639,436
Pass [Member] \| SBA [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	284,492	271,625
Pass [Member] \| SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	264,479	238,189
Pass [Member] \| Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	80,681	45,594
Pass [Member] \| Consumer and other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	74,640	72,411
Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	212,154	192,175
Special Mention [Member] \| SBA [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	4,679	6,756
Special Mention [Member] \| SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	943	8
Special Mention [Member] \| Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	262	339
Special Mention [Member] \| Consumer and other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,151	1,983
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	78,658	56,102
Substandard [Member] \| SBA [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,737	10,219
Substandard [Member] \| SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	602	2,457
Substandard [Member] \| Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	183
Substandard [Member] \| Consumer and other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	990	271
Doubtful & Loss [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans
Doubtful & Loss [Member] \| SBA [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans
Doubtful & Loss [Member] \| SFR mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans
Doubtful & Loss [Member] \| Municipal Lease Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans
Doubtful & Loss [Member] \| Consumer and other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans