Loans and Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses by Loan Category (Detail) - USD ($) $ in Thousands		3 Months Ended
Jan. 01, 2022	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 97,787	$ 97,787	$ 113,031
Charge-offs		(1,607)	(1,982)
Recoveries		1,385	611
Release of allowance for loan losses		(485)	(580)
Ending balance		124,166	111,080
Financing receivable, accrued interest, before allowance for credit loss		31,400
Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	27,086	27,086
Financing receivable, allowance for credit loss, purchased with credit deterioration, increase	100
Commercial and industrial \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	18,018	18,018	26,617
Charge-offs		(1)	0
Recoveries		250	9
Release of allowance for loan losses		(2,959)	(1,220)
Ending balance		26,841	25,406
Commercial and industrial \| Commercial Portfolio Segment \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	11,533	11,533
Commercial real estate \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	52,373	52,373	54,569
Charge-offs		0	(234)
Recoveries		14	0
Release of allowance for loan losses		(1,120)	803
Ending balance		44,612	55,138
Commercial real estate \| Commercial Portfolio Segment \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(6,655)	(6,655)
Commercial construction \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,585	2,585	4,553
Charge-offs		0	0
Recoveries		0	0
Release of allowance for loan losses		344	(1,203)
Ending balance		4,414	3,350
Commercial construction \| Commercial Portfolio Segment \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,485	1,485
Business Banking \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	10,983	10,983	13,152
Charge-offs		(945)	(1,384)
Recoveries		928	365
Release of allowance for loan losses		143	1,371
Ending balance		17,269	13,504
Business Banking \| Commercial Portfolio Segment \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,160	6,160
Residential real estate \| Residential Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,556	6,556	6,435
Charge-offs		0	0
Recoveries		10	10
Release of allowance for loan losses		2,188	(210)
Ending balance		22,243	6,235
Residential real estate \| Residential Portfolio Segment \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	13,489	13,489
Consumer home equity \| Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,722	3,722	3,744
Charge-offs		0	0
Recoveries		4	71
Release of allowance for loan losses		435	(239)
Ending balance		6,018	3,576
Consumer home equity \| Consumer Portfolio Segment \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,857	1,857
Other Consumer \| Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,308	3,308	3,467
Charge-offs		(661)	(364)
Recoveries		179	156
Release of allowance for loan losses		484	239
Ending balance		2,769	3,498
Other Consumer \| Consumer Portfolio Segment \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(541)	(541)
Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	242	242	494
Charge-offs		0	0
Recoveries		0	0
Release of allowance for loan losses		0	(121)
Ending balance		0	$ 373
Other \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ (242)	$ (242)

Amount, before allowance for credit loss, of accrued interest on financing receivable.

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