Loans and Allowance for Credit Losses - Summary of Internal Risk-rating Categories (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
2022	$ 2,492,207
2021	2,477,355
2020	1,676,860
2019	1,168,907
2018	823,239
Prior	2,629,119
Revolving Loans	1,597,708
Revolving Loans Converted to Term Loans	19,210
Total	12,884,605	$ 12,281,510
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	603,019
2021	485,125
2020	441,976
2019	225,396
2018	121,592
Prior	655,817
Revolving Loans	468,494
Revolving Loans Converted to Term Loans	3,753
Total	3,005,172	2,960,527
Commercial and industrial | Pass | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	602,715
2021	467,826
2020	439,013
2019	225,164
2018	115,237
Prior	647,820
Revolving Loans	463,873
Revolving Loans Converted to Term Loans	3,407
Total	2,965,055
Commercial and industrial | Special Mention | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	185
2018	3,667
Prior	12
Revolving Loans	900
Revolving Loans Converted to Term Loans	0
Total	4,764
Commercial and industrial | Substandard | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	304
2021	13,387
2020	2,963
2019	47
2018	2,688
Prior	7,948
Revolving Loans	390
Revolving Loans Converted to Term Loans	346
Total	28,073
Commercial and industrial | Doubtful | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	3,912
2020	0
2019	0
2018	0
Prior	37
Revolving Loans	3,331
Revolving Loans Converted to Term Loans	0
Total	7,280
Commercial and industrial | Loss | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	1,182,661
2021	835,860
2020	611,120
2019	640,700
2018	515,107
Prior	1,138,946
Revolving Loans	53,902
Revolving Loans Converted to Term Loans	4,231
Total	4,982,527	4,522,513
Commercial real estate | Pass | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	1,179,141
2021	835,810
2020	592,293
2019	620,120
2018	463,910
Prior	1,092,428
Revolving Loans	45,902
Revolving Loans Converted to Term Loans	4,231
Total	4,833,835
Commercial real estate | Special Mention | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	16,144
2019	703
2018	35,360
Prior	9,986
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	62,193
Commercial real estate | Substandard | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	3,520
2021	50
2020	2,683
2019	19,877
2018	15,837
Prior	36,532
Revolving Loans	8,000
Revolving Loans Converted to Term Loans	0
Total	86,499
Commercial real estate | Doubtful | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial real estate | Loss | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	71,700
2021	169,318
2020	27,021
2019	32,909
2018	0
Prior	0
Revolving Loans	11,524
Revolving Loans Converted to Term Loans	0
Total	312,472	222,328
Commercial construction | Pass | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	71,700
2021	169,318
2020	24,920
2019	32,909
2018	0
Prior	0
Revolving Loans	11,524
Revolving Loans Converted to Term Loans	0
Total	310,371
Commercial construction | Special Mention | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	2,101
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	2,101
Commercial construction | Substandard | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial construction | Doubtful | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial construction | Loss | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Business banking | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	139,053
2021	227,015
2020	181,485
2019	138,493
2018	67,037
Prior	263,078
Revolving Loans	80,180
Revolving Loans Converted to Term Loans	4,678
Total	1,101,019	1,334,694
Business banking | Pass | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	139,053
2021	224,855
2020	175,102
2019	130,091
2018	62,448
Prior	246,849
Revolving Loans	78,458
Revolving Loans Converted to Term Loans	3,908
Total	1,060,764
Business banking | Special Mention | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	4,704
2019	4,139
2018	3,820
Prior	5,729
Revolving Loans	1,070
Revolving Loans Converted to Term Loans	0
Total	19,462
Business banking | Substandard | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	2,160
2020	1,679
2019	4,072
2018	769
Prior	10,418
Revolving Loans	652
Revolving Loans Converted to Term Loans	770
Total	20,520
Business banking | Doubtful | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	191
2018	0
Prior	82
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	273
Business banking | Loss | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Residential real estate | Residential Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
2022	378,933
2021	713,878
2020	389,910
2019	105,878
2018	72,352
Prior	469,746
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	2,130,697	1,926,810
Residential real estate | Residential Real Estate | Current and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	378,210
2021	711,207
2020	389,001
2019	104,011
2018	70,055
Prior	455,291
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	2,107,775
Residential real estate | Residential Real Estate | 30-89 days past due and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	723
2021	2,671
2020	707
2019	1,574
2018	1,281
Prior	7,453
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	14,409
Residential real estate | Residential Real Estate | Loans 90 days or more past due and still accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Residential real estate | Residential Real Estate | Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	202
2019	293
2018	1,016
Prior	7,002
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	8,513
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	74,271
2021	11,284
2020	6,113
2019	5,228
2018	23,072
Prior	80,511
Revolving Loans	964,974
Revolving Loans Converted to Term Loans	6,538
Total	1,171,991	1,100,153
Consumer home equity | Consumer Portfolio Segment | Current and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	74,271
2021	11,284
2020	6,113
2019	5,145
2018	22,589
Prior	78,717
Revolving Loans	956,474
Revolving Loans Converted to Term Loans	6,378
Total	1,160,971
Consumer home equity | Consumer Portfolio Segment | 30-89 days past due and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	83
2018	101
Prior	646
Revolving Loans	5,110
Revolving Loans Converted to Term Loans	0
Total	5,940
Consumer home equity | Consumer Portfolio Segment | Loans 90 days or more past due and still accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Consumer home equity | Consumer Portfolio Segment | Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	382
Prior	1,148
Revolving Loans	3,390
Revolving Loans Converted to Term Loans	160
Total	5,080
Other Consumer | Consumer Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	42,570
2021	34,875
2020	19,235
2019	20,303
2018	24,079
Prior	21,021
Revolving Loans	18,634
Revolving Loans Converted to Term Loans	10
Total	180,727	$ 214,485
Other Consumer | Consumer Portfolio Segment | Current and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	42,452
2021	34,736
2020	19,085
2019	20,170
2018	23,645
Prior	20,694
Revolving Loans	18,490
Revolving Loans Converted to Term Loans	10
Total	179,282
Other Consumer | Consumer Portfolio Segment | 30-89 days past due and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	77
2021	114
2020	94
2019	59
2018	354
Prior	220
Revolving Loans	52
Revolving Loans Converted to Term Loans	0
Total	970
Other Consumer | Consumer Portfolio Segment | Loans 90 days or more past due and still accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Other Consumer | Consumer Portfolio Segment | Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2022	41
2021	25
2020	56
2019	74
2018	80
Prior	107
Revolving Loans	92
Revolving Loans Converted to Term Loans	0
Total	$ 475