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, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
2025	$ 167,225	$ 570,662
2024	472,852	1,495,356
2023	565,459	486,523
2022	1,476,302	1,284,963
2021	1,257,936	1,004,855
Prior	3,536,139	2,645,131
Revolving loans amortized cost basis	823,891	990,088
Revolving loans converted to term loans	63,828	58,854
Total	8,363,632	8,536,432
gross charge		300
Gross charge-offs Current year	40
Gross charge-off prior		3,609
Gross Charge Offs Revolving Loans Amortized Term Loans		1
Gross charge-offs Revolving loans converted to term loans		498
Gross charge-offs total	40	4,408
Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	119,579	310,235
2024	309,761	1,259,406
2023	411,168	1,097,229
2022	1,248,299	424,701
2021	1,077,577	860,687
Prior	3,074,917	2,308,579
Revolving loans amortized cost basis	206,182	207,624
Revolving loans converted to term loans	43,121	38,991
Total	6,490,604	6,507,452
Gross charge-off prior		2,258
Gross charge-offs total		2,258
Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	7,717
2024	7,020	8,050
2023	319	0
2022	8,367	315
2021	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	15,706	16,082
SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	6,795	33,531
2024	32,690	47,974
2023	15,905	49,147
2022	47,615	16,064
2021	47,810	28,449
Prior	121,029	97,848
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	271,844	273,013
Gross charge-offs Current year	19
Gross charge-off prior		165
Gross charge-offs total	19	165
SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	254
2022	0	0
2021	133	520
Prior	46	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	179	774
Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	34,204	101,284
2024	96,295	113,531
2023	115,341	69,886
2022	106,501	105,484
2021	64,520	69,505
Prior	181,670	122,244
Revolving loans amortized cost basis	328,762	328,280
Revolving loans converted to term loans	15,008	14,964
Total	942,301	925,178
gross charge		300
Gross charge-offs Current year	21
Gross charge-off prior		1,186
Gross charge-offs Revolving loans converted to term loans		495
Gross charge-offs total	21	1,981
Dairy And Livestock And Agribusiness [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	729	0
2023	0	3,713
2022	0	596
2021	597	786
Prior	953	201
Revolving loans amortized cost basis	248,080	412,145
Revolving loans converted to term loans	2,173	2,463
Total	252,532	419,904
Municipal Lease Finance Receivables [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	2,799	5,111
2023	0	2,540
2022	5,095	24,715
2021	24,714	5,140
Prior	32,595	28,608
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	65,203	66,114
SFR mortgage [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	5,894	20,261
2024	18,617	21,055
2023	19,979	59,763
2022	59,518	41,156
2021	40,891	39,626
Prior	124,318	87,027
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	276	284
Total	269,493	269,172
Consumer, Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	753	7,242
2024	4,941	3,043
2023	2,747	1,521
2022	907	1,980
2021	1,694	142
Prior	611	624
Revolving loans amortized cost basis	40,867	42,039
Revolving loans converted to term loans	3,250	2,152
Total	55,770	58,743
Gross Charge Offs Revolving Loans Amortized Term Loans		1
Gross charge-offs Revolving loans converted to term loans		3
Gross charge-offs total		4
Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	166,051	560,266
2024	457,904	1,448,946
2023	551,874	480,552
2022	1,423,815	1,250,781
2021	1,224,605	966,628
Prior	3,345,336	2,495,112
Revolving loans amortized cost basis	755,728	886,023
Revolving loans converted to term loans	45,276	45,785
Total	7,970,589	8,134,093
Pass [Member] \| Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	118,405	307,984
2024	298,954	1,216,126
2023	402,954	1,066,694
2022	1,199,575	419,547
2021	1,047,396	828,493
Prior	2,900,403	2,170,119
Revolving loans amortized cost basis	195,573	197,991
Revolving loans converted to term loans	36,343	37,704
Total	6,199,603	6,244,658
Pass [Member] \| Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	7,717
2024	7,020	8,050
2023	319	0
2022	8,367	315
2021	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	15,706	16,082
Pass [Member] \| SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	6,795	33,531
2024	29,325	46,393
2023	15,905	47,810
2022	46,045	16,064
2021	46,482	23,733
Prior	111,111	92,012
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	255,663	259,543
Pass [Member] \| SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	254
2022	0	0
2021	133	520
Prior	46	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	179	774
Pass [Member] \| Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	34,204	100,465
2024	95,519	111,982
2023	109,970	67,706
2022	104,308	100,242
2021	62,801	69,084
Prior	177,705	118,069
Revolving loans amortized cost basis	314,411	318,147
Revolving loans converted to term loans	5,974	6,213
Total	904,892	891,908
Pass [Member] \| Dairy And Livestock And Agribusiness [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	729	0
2023	0	812
2022	0	596
2021	597	786
Prior	893	141
Revolving loans amortized cost basis	204,881	327,850
Revolving loans converted to term loans	6	13
Total	207,106	330,198
Pass [Member] \| Municipal Lease Finance Receivables [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	2,799	5,111
2023	0	2,540
2022	5,095	24,715
2021	24,714	5,140
Prior	32,496	28,510
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	65,104	66,016
Pass [Member] \| SFR mortgage [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	5,894	20,261
2024	18,617	21,055
2023	19,979	59,763
2022	59,518	41,156
2021	40,891	38,730
Prior	122,071	85,637
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	266,970	266,602
Pass [Member] \| Consumer, Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	753	7,242
2024	4,941	3,043
2023	2,747	1,521
2022	907	1,850
2021	1,591	142
Prior	611	624
Revolving loans amortized cost basis	40,863	42,035
Revolving loans converted to term loans	2,953	1,855
Total	55,366	58,312
Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	7,123
2024	13,774	37,531
2023	9,831	4,795
2022	43,717	25,114
2021	24,112	23,089
Prior	139,627	110,715
Revolving loans amortized cost basis	54,108	96,372
Revolving loans converted to term loans	13,705	8,051
Total	298,874	312,790
Special Mention [Member] \| Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	1,075
2024	9,633	36,505
2023	7,534	21,478
2022	41,993	4,910
2021	21,203	17,056
Prior	127,980	104,201
Revolving loans amortized cost basis	4,826	3,937
Revolving loans converted to term loans	6,778	1,287
Total	219,947	190,449
Special Mention [Member] \| Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	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] \| SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	3,365	0
2023	0	1,337
2022	0	0
2021	1,328	4,716
Prior	6,293	1,830
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	10,986	7,883
Special Mention [Member] \| SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	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]
2025	0	819
2024	776	1,026
2023	2,297	2,169
2022	1,724	2,213
2021	1,478	421
Prior	3,965	4,175
Revolving loans amortized cost basis	12,604	8,136
Revolving loans converted to term loans	5,284	4,830
Total	28,128	23,789
Special Mention [Member] \| Dairy And Livestock And Agribusiness [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	2,901
2022	0	0
2021	0	0
Prior	0	0
Revolving loans amortized cost basis	36,674	84,295
Revolving loans converted to term loans	1,367	1,650
Total	38,041	88,846
Special Mention [Member] \| Municipal Lease Finance Receivables [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	0	0
Prior	99	98
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	99	98
Special Mention [Member] \| SFR mortgage [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	0	896
Prior	1,290	411
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	276	284
Total	1,566	1,591
Special Mention [Member] \| Consumer, Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	130
2021	103	0
Prior	0	0
Revolving loans amortized cost basis	4	4
Revolving loans converted to term loans	0	0
Total	107	134
Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	1,174	3,273
2024	1,174	8,879
2023	3,754	1,176
2022	8,770	9,068
2021	9,219	15,138
Prior	51,176	39,304
Revolving loans amortized cost basis	14,055	7,693
Revolving loans converted to term loans	4,847	5,018
Total	94,169	89,549
Substandard [Member] \| Commercial real estate loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	1,174	1,176
2024	1,174	6,775
2023	680	9,057
2022	6,731	244
2021	8,978	15,138
Prior	46,534	34,259
Revolving loans amortized cost basis	5,783	5,696
Revolving loans converted to term loans	0	0
Total	71,054	72,345
Substandard [Member] \| Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	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] \| SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	523
2023	0	11
2022	1,570	3,029
2021	0	0
Prior	3,625	0
Revolving loans amortized cost basis	0	1,997
Revolving loans converted to term loans	0	3,921
Total	5,195	9,481
Substandard [Member] \| SBA - Paycheck Protection Program (PPP) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	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]
2025	0	0
2024	0	1,581
2023	3,074	0
2022	469	0
2021	241	0
Prior	0	4,006
Revolving loans amortized cost basis	1,747	0
Revolving loans converted to term loans	3,750	0
Total	9,281	5,587
Substandard [Member] \| Dairy And Livestock And Agribusiness [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	0	0
Prior	60	60
Revolving loans amortized cost basis	6,525	0
Revolving loans converted to term loans	800	800
Total	7,385	860
Substandard [Member] \| Municipal Lease Finance Receivables [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0
2022	0
2021	0
Prior	0
Revolving loans amortized cost basis	0
Revolving loans converted to term loans	0
Total	0
Substandard [Member] \| SFR mortgage [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	0	0
Prior	957	979
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	0	0
Total	957	979
Substandard [Member] \| Consumer, Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term loans	297	297
Total	297	297
Doubtful [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	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]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	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]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	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]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	0	0
Prior	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