Loans and the Allowance for Credit Losses - Summary of Amortized Cost Basis Loan Balances by Year of Origination and Credit Quality Indicator (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 11,873,167	$ 11,638,461
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	15,226	15,152
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,605	9,729
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	24,957	25,302
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	11,894	12,828
Amortized Cost Basis by Origination Year 2023	1,752	1,959
Amortized Cost Basis by Origination Year 2022	2,366	1,568
Amortized Cost Basis by Origination Year 2021	1,316	2,449
Amortized Cost Basis by Origination Year 2020	2,568	1,964
Amortized Cost Basis by Origination Year, Prior to 2019	25,455	26,482
Revolving Loans	693,305	685,163
Revolving Loans Converted to Term	2,317	1,806
Total loans	740,973	734,219
Home Equity [Member] | Current [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	11,894	12,675
Amortized Cost Basis by Origination Year 2023	993	1,235
Amortized Cost Basis by Origination Year 2022	1,676	1,467
Amortized Cost Basis by Origination Year 2021	1,059	1,571
Amortized Cost Basis by Origination Year 2020	1,840	1,614
Amortized Cost Basis by Origination Year, Prior to 2019	21,352	22,484
Revolving Loans	689,877	681,848
Revolving Loans Converted to Term	1,830	1,399
Total loans	730,521	724,293
Home Equity [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		34
Amortized Cost Basis by Origination Year 2023	59	193
Amortized Cost Basis by Origination Year 2022	251	85
Amortized Cost Basis by Origination Year 2021	80	73
Amortized Cost Basis by Origination Year 2020	57	44
Amortized Cost Basis by Origination Year, Prior to 2019	841	947
Revolving Loans	3,425	3,315
Revolving Loans Converted to Term	156
Total loans	4,869	4,691
Home Equity [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		119
Amortized Cost Basis by Origination Year 2023	700	318
Amortized Cost Basis by Origination Year 2022	217	16
Amortized Cost Basis by Origination Year 2021		68
Amortized Cost Basis by Origination Year 2020	14	76
Amortized Cost Basis by Origination Year, Prior to 2019	1,308	524
Revolving Loans	3
Revolving Loans Converted to Term	7	77
Total loans	2,249	1,198
Home Equity [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2023		213
Amortized Cost Basis by Origination Year 2022	222
Amortized Cost Basis by Origination Year 2021	177	737
Amortized Cost Basis by Origination Year 2020	657	230
Amortized Cost Basis by Origination Year, Prior to 2019	1,954	2,527
Revolving Loans Converted to Term	324	330
Total loans	3,334	4,037
Home Equity [Member] | Current-period gross charge-offs [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2023	20	139
Amortized Cost Basis by Origination Year 2022	62	57
Amortized Cost Basis by Origination Year 2021		29
Amortized Cost Basis by Origination Year 2020	35	79
Amortized Cost Basis by Origination Year, Prior to 2019	72	615
Revolving Loans	20	6
Revolving Loans Converted to Term	7
Total loans	216	925
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,754,933	6,565,448
Commercial Real Estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,852	4,416
Commercial Real Estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,226	3,627
Commercial Real Estate [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	11,859	10,594
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	34,392	277,790
Amortized Cost Basis by Origination Year 2023	278,392	430,634
Amortized Cost Basis by Origination Year 2022	394,217	445,356
Amortized Cost Basis by Origination Year 2021	435,317	185,480
Amortized Cost Basis by Origination Year 2020	182,605	86,412
Amortized Cost Basis by Origination Year, Prior to 2019	535,684	464,727
Revolving Loans Converted to Term	608,750	548,175
Total loans	2,469,357	2,438,574
Residential Real Estate [Member] | Current [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	34,392	277,790
Amortized Cost Basis by Origination Year 2023	278,392	429,835
Amortized Cost Basis by Origination Year 2022	393,426	445,322
Amortized Cost Basis by Origination Year 2021	435,283	185,139
Amortized Cost Basis by Origination Year 2020	182,098	86,149
Amortized Cost Basis by Origination Year, Prior to 2019	527,391	456,818
Revolving Loans Converted to Term	607,421	548,147
Total loans	2,458,403	2,429,200
Residential Real Estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2020	339
Amortized Cost Basis by Origination Year, Prior to 2019	2,728	1,572
Revolving Loans Converted to Term	93
Total loans	3,160	1,572
Residential Real Estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2021		341
Amortized Cost Basis by Origination Year, Prior to 2019	478	2,130
Total loans	478	2,471
Residential Real Estate [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2023		799
Amortized Cost Basis by Origination Year 2022	791	34
Amortized Cost Basis by Origination Year 2021	34
Amortized Cost Basis by Origination Year 2020	168	263
Amortized Cost Basis by Origination Year, Prior to 2019	5,087	4,207
Revolving Loans Converted to Term	1,236	28
Total loans	7,316	5,331
Residential Real Estate [Member] | Current-period gross charge-offs [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2020		5
Amortized Cost Basis by Origination Year, Prior to 2019	77	387
Revolving Loans Converted to Term	58
Total loans	135	392
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	19,105	85,480
Amortized Cost Basis by Origination Year 2023	77,189	60,006
Amortized Cost Basis by Origination Year 2022	54,114	22,853
Amortized Cost Basis by Origination Year 2021	20,016	13,707
Amortized Cost Basis by Origination Year 2020	11,288	11,134
Amortized Cost Basis by Origination Year, Prior to 2019	19,076	12,429
Revolving Loans	23,944	23,948
Revolving Loans Converted to Term		4
Total loans	224,732	229,561
Consumer [Member] | Current [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	19,019	84,526
Amortized Cost Basis by Origination Year 2023	76,043	57,661
Amortized Cost Basis by Origination Year 2022	52,536	21,592
Amortized Cost Basis by Origination Year 2021	19,109	13,189
Amortized Cost Basis by Origination Year 2020	10,962	10,958
Amortized Cost Basis by Origination Year, Prior to 2019	18,694	12,143
Revolving Loans	23,939	23,916
Revolving Loans Converted to Term		4
Total loans	220,302	223,989
Consumer [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	86	699
Amortized Cost Basis by Origination Year 2023	709	1,526
Amortized Cost Basis by Origination Year 2022	950	952
Amortized Cost Basis by Origination Year 2021	779	343
Amortized Cost Basis by Origination Year 2020	183	162
Amortized Cost Basis by Origination Year, Prior to 2019	193	119
Revolving Loans	5	32
Total loans	2,905	3,833
Consumer [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		191
Amortized Cost Basis by Origination Year 2023	281	616
Amortized Cost Basis by Origination Year 2022	519	195
Amortized Cost Basis by Origination Year 2021	64	112
Amortized Cost Basis by Origination Year 2020	73	5
Amortized Cost Basis by Origination Year, Prior to 2019	82	59
Total loans	1,019	1,178
Consumer [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		64
Amortized Cost Basis by Origination Year 2023	156	203
Amortized Cost Basis by Origination Year 2022	109	114
Amortized Cost Basis by Origination Year 2021	64	63
Amortized Cost Basis by Origination Year 2020	70	9
Amortized Cost Basis by Origination Year, Prior to 2019	107	108
Total loans	506	561
Consumer [Member] | Current-period gross charge-offs [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		251
Amortized Cost Basis by Origination Year 2023	189	1,921
Amortized Cost Basis by Origination Year 2022	587	901
Amortized Cost Basis by Origination Year 2021	213	301
Amortized Cost Basis by Origination Year 2020	52	100
Amortized Cost Basis by Origination Year, Prior to 2019	57	247
Revolving Loans		4
Total loans	1,098	3,725
Commercial Real Estate - Land and Construction [Member] | Current-period gross charge-offs [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2023	813
Revolving Loans Converted to Term		222
Total loans	813	222
Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	24,606	290,954
Amortized Cost Basis by Origination Year 2023	331,586	349,549
Amortized Cost Basis by Origination Year 2022	379,849	145,043
Amortized Cost Basis by Origination Year 2021	152,158	54,172
Amortized Cost Basis by Origination Year 2020	24,478	48,655
Amortized Cost Basis by Origination Year, Prior to 2019	60,405	35,942
Revolving Loans	62,776	82,587
Revolving Loans Converted to Term	51,791	48,963
Total loans	1,087,649	1,055,865
Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	24,606	290,954
Amortized Cost Basis by Origination Year 2023	331,376	349,549
Amortized Cost Basis by Origination Year 2022	379,849	145,043
Amortized Cost Basis by Origination Year 2021	152,158	54,172
Amortized Cost Basis by Origination Year 2020	24,478	48,655
Amortized Cost Basis by Origination Year, Prior to 2019	60,384	35,917
Revolving Loans	62,496	82,288
Revolving Loans Converted to Term	49,628	46,781
Total loans	1,084,975	1,053,359
Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year, Prior to 2019	14	16
Revolving Loans	280	299
Revolving Loans Converted to Term	2,163	2,182
Total loans	2,457	2,497
Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member] | Classified - substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2023	210
Amortized Cost Basis by Origination Year, Prior to 2019	7	9
Total loans	217	9
Commercial Real Estate - Improved Property [Member] | Current-period gross charge-offs [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2022		372
Amortized Cost Basis by Origination Year, Prior to 2019	58	1,505
Total loans	58	1,877
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	107,508	496,063
Amortized Cost Basis by Origination Year 2023	515,096	1,093,322
Amortized Cost Basis by Origination Year 2022	1,107,690	612,401
Amortized Cost Basis by Origination Year 2021	585,604	588,343
Amortized Cost Basis by Origination Year 2020	625,540	543,180
Amortized Cost Basis by Origination Year, Prior to 2019	2,266,323	1,787,604
Revolving Loans	117,275	105,840
Revolving Loans Converted to Term	342,248	282,830
Total loans	5,667,284	5,509,583
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,852	4,416
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,226	3,627
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	11,859	10,594
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	107,508	494,142
Amortized Cost Basis by Origination Year 2023	500,262	1,076,535
Amortized Cost Basis by Origination Year 2022	1,090,763	603,354
Amortized Cost Basis by Origination Year 2021	576,509	581,540
Amortized Cost Basis by Origination Year 2020	618,834	514,523
Amortized Cost Basis by Origination Year, Prior to 2019	2,165,451	1,706,804
Revolving Loans	115,578	103,467
Revolving Loans Converted to Term	316,758	257,029
Total loans	5,491,663	5,337,394
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2023	12,928	16,270
Amortized Cost Basis by Origination Year 2022	11,434	8,630
Amortized Cost Basis by Origination Year 2021	8,319	4,387
Amortized Cost Basis by Origination Year 2020	4,380	5,185
Amortized Cost Basis by Origination Year, Prior to 2019	39,434	44,861
Revolving Loans	1,697	2,373
Revolving Loans Converted to Term	25,456	25,767
Total loans	103,648	107,473
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member] | Classified - substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		1,921
Amortized Cost Basis by Origination Year 2023	1,906	517
Amortized Cost Basis by Origination Year 2022	5,493	417
Amortized Cost Basis by Origination Year 2021	776	2,416
Amortized Cost Basis by Origination Year 2020	2,326	23,472
Amortized Cost Basis by Origination Year, Prior to 2019	61,438	35,939
Revolving Loans Converted to Term	34	34
Total loans	71,973	64,716
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	60,297	239,554
Amortized Cost Basis by Origination Year 2023	218,694	235,503
Amortized Cost Basis by Origination Year 2022	228,484	140,482
Amortized Cost Basis by Origination Year 2021	136,143	80,591
Amortized Cost Basis by Origination Year 2020	70,478	47,418
Amortized Cost Basis by Origination Year, Prior to 2019	316,354	286,268
Revolving Loans	585,945	567,823
Revolving Loans Converted to Term	66,777	73,020
Total loans	1,683,172	1,670,659
Commercial and Industrial [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,440	640
Commercial and Industrial [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	633	1,255
Commercial and Industrial [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,942	4,779
Commercial and Industrial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024	60,297	238,427
Amortized Cost Basis by Origination Year 2023	217,013	234,520
Amortized Cost Basis by Origination Year 2022	226,435	136,998
Amortized Cost Basis by Origination Year 2021	135,148	78,836
Amortized Cost Basis by Origination Year 2020	68,852	39,259
Amortized Cost Basis by Origination Year, Prior to 2019	275,734	252,826
Revolving Loans	546,174	541,400
Revolving Loans Converted to Term	58,380	64,417
Total loans	1,588,033	1,586,683
Commercial and Industrial [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		1,094
Amortized Cost Basis by Origination Year 2023	1,276	834
Amortized Cost Basis by Origination Year 2022	1,174	3,169
Amortized Cost Basis by Origination Year 2021	254	1,490
Amortized Cost Basis by Origination Year 2020	1,387	7,334
Amortized Cost Basis by Origination Year, Prior to 2019	38,277	31,526
Revolving Loans	15,626	20,626
Revolving Loans Converted to Term	7,437	7,131
Total loans	65,431	73,204
Commercial and Industrial [Member] | Classified - substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		33
Amortized Cost Basis by Origination Year 2023	405	149
Amortized Cost Basis by Origination Year 2022	875	315
Amortized Cost Basis by Origination Year 2021	741	265
Amortized Cost Basis by Origination Year 2020	239	825
Amortized Cost Basis by Origination Year, Prior to 2019	2,343	1,916
Revolving Loans	24,145	5,797
Revolving Loans Converted to Term	960	1,472
Total loans	29,708	10,772
Commercial and Industrial [Member] | Current-period gross charge-offs [Member]
Financing Receivable, Recorded Investment [Line Items]
Amortized Cost Basis by Origination Year 2024		98
Amortized Cost Basis by Origination Year 2023	274	205
Amortized Cost Basis by Origination Year 2022	126	603
Amortized Cost Basis by Origination Year 2021		353
Amortized Cost Basis by Origination Year 2020	53	20
Amortized Cost Basis by Origination Year, Prior to 2019	325	463
Revolving Loans Converted to Term	4,032	541
Total loans	$ 4,810	$ 2,283