Loans and Allowance for Credit Losses - Summary of Changes in Allowance for Loan Losses by Loan Category (Details) - USD ($) $ in Thousands		12 Months Ended
Jan. 01, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 97,787	$ 142,211	$ 97,787	$ 113,031
Charge-offs		(15,092)	(4,831)	(9,002)
Recoveries		2,965	4,244	3,444
Provision (release)		20,052	17,925	(9,686)
Ending balance		148,993	142,211	97,787
Allowance for loan losses		148,993	142,211	97,787
Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	27,086	(1,143)	27,086
Ending balance			(1,143)	27,086
Allowance for loan losses			(1,143)	27,086
Cumulative effect accounting adjustment \| Accounting Standards Update 2022-02
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		(1,100)
Ending balance			(1,100)
Allowance for loan losses			(1,100)
Cumulative effect accounting adjustment \| Accounting Standards Update 2016-13
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	27,100		27,100
Ending balance				27,100
Allowance for loan losses				27,100
PCI loan balances to PCD and the associated gross-up	100
Other Class Of Financing Receivable [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	242	0	242	494
Charge-offs			0	0
Recoveries			0	0
Provision (release)			0	(252)
Ending balance			0	242
Allowance for loan losses			0	242
Other Class Of Financing Receivable [Member] \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(242)		(242)
Ending balance				(242)
Allowance for loan losses				(242)
Commercial Portfolio Segment \| Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	18,018	26,859	18,018	26,617
Charge-offs		(13)	(269)	(1,558)
Recoveries		296	1,322	935
Provision (release)		(230)	(3,745)	(7,976)
Ending balance		26,959	26,859	18,018
Allowance for loan losses		26,959	26,859	18,018
Commercial Portfolio Segment \| Commercial and industrial \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	11,533	47	11,533
Ending balance			47	11,533
Allowance for loan losses			47	11,533
Commercial Portfolio Segment \| Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	52,373	54,730	52,373	54,569
Charge-offs		(8,008)	0	(247)
Recoveries		198	91	4
Provision (release)		18,555	8,921	(1,953)
Ending balance		65,475	54,730	52,373
Allowance for loan losses		65,475	54,730	52,373
Commercial Portfolio Segment \| Commercial real estate \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(6,655)	0	(6,655)
Ending balance			0	(6,655)
Allowance for loan losses			0	(6,655)
Commercial Portfolio Segment \| Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,585	7,085	2,585	4,553
Charge-offs		0	0	0
Recoveries		0	0	0
Provision (release)		(419)	3,015	(1,968)
Ending balance		6,666	7,085	2,585
Allowance for loan losses		6,666	7,085	2,585
Commercial Portfolio Segment \| Commercial construction \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,485	0	1,485
Ending balance			0	1,485
Allowance for loan losses			0	1,485
Commercial Portfolio Segment \| Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	10,983	16,189	10,983	13,152
Charge-offs		(4,645)	(2,292)	(5,091)
Recoveries		1,867	2,069	1,524
Provision (release)		1,642	(731)	1,398
Ending balance		14,913	16,189	10,983
Allowance for loan losses		14,913	16,189	10,983
Commercial Portfolio Segment \| Business banking \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,160	(140)	6,160
Ending balance			(140)	6,160
Allowance for loan losses			(140)	6,160
Residential Portfolio Segment \| Residential real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,556	28,129	6,556	6,435
Charge-offs		0	0	(35)
Recoveries		97	94	122
Provision (release)		(1,423)	7,990	34
Ending balance		25,954	28,129	6,556
Allowance for loan losses		25,954	28,129	6,556
Residential Portfolio Segment \| Residential real estate \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	13,489	(849)	13,489
Ending balance			(849)	13,489
Allowance for loan losses			(849)	13,489
Consumer Portfolio Segment \| Consumer home equity
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,722	6,454	3,722	3,744
Charge-offs		(7)	(1)	(24)
Recoveries		41	24	185
Provision (release)		(692)	852	(183)
Ending balance		5,595	6,454	3,722
Allowance for loan losses		5,595	6,454	3,722
Consumer Portfolio Segment \| Consumer home equity \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,857	(201)	1,857
Ending balance			(201)	1,857
Allowance for loan losses			(201)	1,857
Consumer Portfolio Segment \| Other Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,308	2,765	3,308	3,467
Charge-offs		(2,419)	(2,269)	(2,047)
Recoveries		466	644	674
Provision (release)		2,619	1,623	1,214
Ending balance		3,431	2,765	3,308
Allowance for loan losses		3,431	2,765	3,308
Consumer Portfolio Segment \| Other Consumer \| Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ (541)	$ 0	(541)
Ending balance			0	(541)
Allowance for loan losses			$ 0	$ (541)

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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-Topic 326
-SubTopic 20
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Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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