Loans and Lease Finance Receivables and Allowance for Credit Losses - Summary of loans by type and origination year, according to our internal risk ratings (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
2024	$ 107,973	$ 651,552
2023	640,327	1,608,241
2022	1,580,443	1,402,964
2021	1,383,515	1,124,447
2020	1,093,100	668,632
Prior	3,022,358	2,453,629
Revolving loans amortized cost basis	891,029	943,285
Revolving loans converted to term loans	51,968	52,160
Total	8,770,713	8,904,910
gross charge	300
Gross charge-off prior	3,534	292
Gross Charge Offs Revolving Loans Amortized Term Loans	1
Gross charge-offs Revolving loans converted to term loans	432	113
Gross charge-offs total	4,267	405
Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	55,331	451,976
2023	446,821	1,327,587
2022	1,311,212	1,152,090
2021	1,142,193	938,359
2020	918,902	554,351
Prior	2,624,299	2,146,639
Revolving loans amortized cost basis	182,840	174,935
Revolving loans converted to term loans	38,940	38,568
Total	6,720,538	6,784,505
Gross charge-off prior	2,258
Gross charge-offs total	2,258
Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	3	1,274
2023	2,513	15,046
2022	12,277	24,418
2021	24,398	8,058
2020	8,066	0
Prior	0	0
Revolving loans amortized cost basis	11,549	17,938
Revolving loans converted to term loans	0	0
Total	58,806	66,734
SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	10,759	20,701
2023	19,621	49,839
2022	49,512	51,038
2021	50,594	34,090
2020	29,184	8,117
Prior	108,650	106,834
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	268,320	270,619
Gross charge-off prior	90	288
Gross charge-offs total	90	288
SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	591	699
2021	1,658	2,037
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	2,249	2,736
Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	28,523	148,909
2023	144,924	144,842
2022	137,716	100,804
2021	91,905	89,295
2020	83,323	72,555
Prior	159,382	99,309
Revolving loans amortized cost basis	307,006	302,555
Revolving loans converted to term loans	10,341	11,626
Total	963,120	969,895
gross charge	300
Gross charge-off prior	1,186
Gross charge-offs Revolving loans converted to term loans	431	109
Gross charge-offs total	1,917	109
Dairy And Livestock And Agribusiness [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	744
2023	432	0
2022	0	1,586
2021	2,020	931
2020	917	105
Prior	322	268
Revolving loans amortized cost basis	347,581	409,257
Revolving loans converted to term loans	352	0
Total	351,624	412,891
Municipal Lease Finance Receivables [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	193	0
2023	0	5,735
2022	5,719	25,803
2021	25,803	5,981
2020	5,733	4,267
Prior	34,584	31,804
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	72,032	73,590
SFR mortgage [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	11,528	23,037
2023	21,979	61,070
2022	60,524	43,573
2021	43,305	44,994
2020	44,745	28,593
Prior	94,086	68,277
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	308	324
Total	276,475	269,868
Consumer Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,636	4,911
2023	4,037	4,122
2022	3,483	2,953
2021	2,706	702
2020	572	644
Prior	1,035	498
Revolving loans amortized cost basis	42,053	38,600
Revolving loans converted to term loans	2,027	1,642
Total	57,549	54,072
Gross charge-off prior		4
Gross Charge Offs Revolving Loans Amortized Term Loans	1
Gross charge-offs Revolving loans converted to term loans	1	4
Gross charge-offs total	2	8
Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	107,295	638,501
2023	624,422	1,593,595
2022	1,565,492	1,381,084
2021	1,356,755	1,065,424
2020	1,034,523	605,169
Prior	2,840,039	2,337,278
Revolving loans amortized cost basis	795,716	854,820
Revolving loans converted to term loans	45,154	44,899
Total	8,369,396	8,520,770
Pass [Member] \| Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	54,653	447,991
2023	441,596	1,315,563
2022	1,299,240	1,133,331
2021	1,120,686	885,590
2020	866,833	497,541
Prior	2,457,881	2,041,329
Revolving loans amortized cost basis	179,725	171,223
Revolving loans converted to term loans	38,940	38,568
Total	6,459,554	6,531,136
Pass [Member] \| Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	3	1,274
2023	2,513	15,046
2022	12,277	22,288
2021	22,289	8,058
2020	8,066	0
Prior	0	0
Revolving loans amortized cost basis	11,549	17,938
Revolving loans converted to term loans	0	0
Total	56,697	64,604
Pass [Member] \| SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	10,759	20,701
2023	19,621	48,212
2022	47,896	51,038
2021	50,594	29,306
2020	24,417	6,236
Prior	102,067	101,856
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	255,354	257,349
Pass [Member] \| SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	591	699
2021	1,658	2,037
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	2,249	2,736
Pass [Member] \| Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	28,523	141,080
2023	135,426	143,847
2022	136,353	100,059
2021	90,310	88,743
2020	82,495	68,352
Prior	151,348	94,027
Revolving loans amortized cost basis	296,236	289,539
Revolving loans converted to term loans	4,688	5,460
Total	925,379	931,107
Pass [Member] \| Dairy And Livestock And Agribusiness [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	296
2023	0	0
2022	0	1,586
2021	685	931
2020	917	80
Prior	262	208
Revolving loans amortized cost basis	266,157	337,525
Revolving loans converted to term loans	270	0
Total	268,291	340,626
Pass [Member] \| Municipal Lease Finance Receivables [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	193	0
2023	0	5,735
2022	5,719	25,803
2021	25,803	5,981
2020	5,733	4,267
Prior	34,402	31,622
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	71,850	73,408
Pass [Member] \| SFR mortgage [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	11,528	22,248
2023	21,229	61,070
2022	60,524	43,573
2021	43,305	44,076
2020	43,832	28,049
Prior	93,044	67,750
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	273,462	266,766
Pass [Member] \| Consumer Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,636	4,911
2023	4,037	4,122
2022	3,483	2,707
2021	2,492	702
2020	572	644
Prior	1,035	486
Revolving loans amortized cost basis	42,049	38,595
Revolving loans converted to term loans	1,256	871
Total	56,560	53,038
Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	678	12,307
2023	15,236	6,262
2022	6,607	18,989
2021	21,760	25,622
2020	25,625	49,639
Prior	133,332	80,928
Revolving loans amortized cost basis	89,547	82,676
Revolving loans converted to term loans	5,452	5,520
Total	298,237	281,943
Special Mention [Member] \| Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	678	3,241
2023	4,556	3,897
2022	3,867	15,868
2021	18,616	19,368
2020	19,117	43,824
Prior	121,713	74,673
Revolving loans amortized cost basis	2,366	2,911
Revolving loans converted to term loans	0	0
Total	170,913	163,782
Special Mention [Member] \| Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	2,130
2021	0	0
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	0	2,130
Special Mention [Member] \| SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	1,627
2022	1,616	0
2021	0	4,784
2020	4,767	1,132
Prior	3,010	1,760
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	9,393	9,303
Special Mention [Member] \| SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	0	0
Special Mention [Member] \| Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	7,829
2023	9,498	738
2022	1,124	745
2021	1,595	552
2020	828	4,114
Prior	7,989	3,986
Revolving loans amortized cost basis	8,133	10,529
Revolving loans converted to term loans	5,279	5,347
Total	34,446	33,840
Special Mention [Member] \| Dairy And Livestock And Agribusiness [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	448
2023	432	0
2022	0	0
2021	1,335	0
2020		25
Prior		0
Revolving loans amortized cost basis	79,044	69,232
Revolving loans converted to term loans		0
Total	80,811	69,705
Special Mention [Member] \| Municipal Lease Finance Receivables [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	182	182
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	182	182
Special Mention [Member] \| SFR mortgage [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	789
2023	750	0
2022	0	246
2021	0	0
2020	913	0
Prior	438	0
Revolving loans amortized cost basis	0	4
Revolving loans converted to term loans	0	173
Total	2,101	423
Special Mention [Member] \| Consumer Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	214	918
2020	0	544
Prior	0	327
Revolving loans amortized cost basis	4	0
Revolving loans converted to term loans	173	0
Total	391	2,578
Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	744
2023	669	8,384
2022	8,344	2,891
2021	5,000	33,401
2020	32,952	13,824
Prior	48,987	35,423
Revolving loans amortized cost basis	5,766	5,789
Revolving loans converted to term loans	1,362	1,741
Total	103,080	102,197
Substandard [Member] \| Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	744
2023	669	8,127
2022	8,105	2,891
2021	2,891	33,401
2020	32,952	12,986
Prior	44,705	30,637
Revolving loans amortized cost basis	749	801
Revolving loans converted to term loans	0	0
Total	90,071	89,587
Substandard [Member] \| Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	2,109	0
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	2,109	0
Substandard [Member] \| SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	749
Prior	3,573	3,218
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	3,573	3,967
Substandard [Member] \| SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	0	0
Substandard [Member] \| Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	257
2022	239	0
2021	0	0
2020	0	89
Prior	45	1,296
Revolving loans amortized cost basis	2,637	2,487
Revolving loans converted to term loans	374	819
Total	3,295	4,948
Substandard [Member] \| Dairy And Livestock And Agribusiness [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023		0
2022	0
2021
2020
Prior	60
Revolving loans amortized cost basis	2,380
Revolving loans converted to term loans	82
Total	2,522
Substandard [Member] \| Municipal Lease Finance Receivables [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	0	60
Revolving loans amortized cost basis	0	2,500
Revolving loans converted to term loans	0	0
Total	0	2,560
Substandard [Member] \| SFR mortgage [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	604	200
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	308	324
Total	912	524
Substandard [Member] \| Consumer Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	0	12
Revolving loans amortized cost basis	0	1
Revolving loans converted to term loans	598	598
Total	598	611
Doubtful [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	0	0
Doubtful [Member] \| Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	0	0
Doubtful [Member] \| Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	0	0
Doubtful [Member] \| SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	0
2020	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0

Loans and Lease Finance Receivables and Allowance for Credit Losses - Summary of loans by type and origination year, according to our internal risk ratings (Detail) - USD ($)
$ in Thousands