Loans and Lease Finance Receivables and Allowance for Credit Losses - Schedule of Balance and Activity Related to Allowance for Loan Losses for Held-for-Investment Loans by Type (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	$ 85,117	$ 65,019
Charge-offs	405	(197)	$ 3,371
Recoveries	130	1,090	198
Initial ACL for PCD Loans at Acquisition		8,605
Provision Recorded at Acquisition		4,932
Provision for (recapture of) credit losses	2,000	(5,668)	25,500
Ending Balance	86,842	85,117	65,019
Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			93,692
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	64,806	50,950
Charge-offs	0	0	0
Recoveries	0	0	0
Initial ACL for PCD Loans at Acquisition		5,086
Provision Recorded at Acquisition		4,127
Provision for (recapture of) credit losses	4,660	(4,643)	24,489
Ending Balance	69,466	64,806	50,950
Commercial Real Estate [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			75,439
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	1,702	765
Charge-offs	0	0	0
Recoveries	12	12	58
Initial ACL for PCD Loans at Acquisition		122
Provision Recorded at Acquisition		58
Provision for (recapture of) credit losses	(437)	(745)	1,227
Ending Balance	1,277	1,702	765
Construction [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			1,934
Small Business Administration [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	2,809	2,668
Charge-offs	288	(127)	223
Recoveries	73	107	23
Initial ACL for PCD Loans at Acquisition		62
Provision Recorded at Acquisition		64
Provision for (recapture of) credit losses	85	(35)	124
Ending Balance	2,679	2,809	2,668
Small Business Administration [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			2,992
SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	0	0
Charge-offs	0		0
Recoveries	0		0
Initial ACL for PCD Loans at Acquisition		0
Provision Recorded at Acquisition		0
Provision for (recapture of) credit losses	0		0
Ending Balance	0	0	0
SBA - Paycheck Protection Program (PPP) [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			0
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	10,206	6,669
Charge-offs	109	(66)	3,019
Recoveries	14	503	12
Initial ACL for PCD Loans at Acquisition		500
Provision Recorded at Acquisition		508
Provision for (recapture of) credit losses	(995)	2,092	2,534
Ending Balance	9,116	10,206	6,669
Commercial and Industrial [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			7,142
Dairy & Livestock and Agribusiness [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	4,400	3,066
Charge-offs	0	0	118
Recoveries	31	468	0
Initial ACL for PCD Loans at Acquisition		2,832
Provision Recorded at Acquisition		149
Provision for (recapture of) credit losses	(1,333)	(2,115)	(765)
Ending Balance	3,098	4,400	3,066
Dairy & Livestock and Agribusiness [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			3,949
Municipal Lease Finance Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	296	100
Charge-offs	0	0	0
Recoveries	0	0	0
Initial ACL for PCD Loans at Acquisition		3
Provision Recorded at Acquisition		26
Provision for (recapture of) credit losses	(86)	167	(26)
Ending Balance	210	296	100
Municipal Lease Finance Receivables [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			74
SFR Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	366	188
Charge-offs	0	0	0
Recoveries	0	0	79
Initial ACL for PCD Loans at Acquisition		0
Provision Recorded at Acquisition		0
Provision for (recapture of) credit losses	169	(178)	(258)
Ending Balance	535	366	188
SFR Mortgage [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			367
Consumer and Other Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	532	613
Charge-offs	8	(4)	11
Recoveries	0	0	26
Initial ACL for PCD Loans at Acquisition		0
Provision Recorded at Acquisition		0
Provision for (recapture of) credit losses	(63)	(77)	1,197
Ending Balance	$ 461	$ 532	613
Consumer and Other Loans [Member] | Impact of ASU 2016-13 Adoption [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance			$ 1,795