Loans, Allowance for Credit Losses and Credit Quality - Financing Receivable Past Due (Details) $ in Thousands		Mar. 31, 2023 USD ($) loan		Dec. 31, 2022 USD ($) loan	Mar. 31, 2022 USD ($)
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		421		481
Total loans		$ 13,947,952	[1]	$ 13,928,675
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		33		35
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		50		46
Number Of Financing Receivables Total Past Due | loan		504		562
Total		$ 13,947,952		$ 13,928,675	$ 13,580,027
Financing Receivable, 90 Days or More Past Due, Still Accruing		23		0
Financing receivable, net deferred costs		5,500		5,000
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		5,233		5,934
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		921		6,560
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		31,848		29,426
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		38,002		41,920
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 13,909,950		$ 13,886,755
Commercial And Industrial [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		5		3
Total loans		$ 1,649,882	[1]	$ 1,635,103
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		1		1
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		2		3
Number Of Financing Receivables Total Past Due | loan		8		7
Total		$ 1,649,882		$ 1,635,103	1,566,192	[1]
Financing Receivable, 90 Days or More Past Due, Still Accruing		0		0
Commercial And Industrial [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		339		49
Commercial And Industrial [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		69		175
Commercial And Industrial [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		23,472		23,726
Commercial And Industrial [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		23,880		23,950
Commercial And Industrial [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 1,626,002		$ 1,611,153
Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		4		7
Total loans		$ 7,820,094	[1]	$ 7,760,230
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		0		5
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		3		3
Number Of Financing Receivables Total Past Due | loan		7		15
Total		$ 7,820,094		$ 7,760,230	7,897,616	[1]
Financing Receivable, 90 Days or More Past Due, Still Accruing		0		0
Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		785		2,052
Commercial Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		0		4,971
Commercial Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		4,846		2,977
Commercial Real Estate [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		5,631		10,000
Commercial Real Estate [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 7,814,463		$ 7,750,230
Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		0		0
Total loans		$ 1,046,310	[1]	$ 1,154,413
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		0		0
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		0		0
Number Of Financing Receivables Total Past Due | loan		0		0
Total		$ 1,046,310		$ 1,154,413	1,153,945	[1]
Financing Receivable, 90 Days or More Past Due, Still Accruing		0		0
Construction Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		0		0
Construction Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		0		0
Construction Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		0		0
Construction Loans [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		0		0
Construction Loans [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 1,046,310		$ 1,154,413
Small Business [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		9		12
Total loans		$ 225,866	[1]	$ 219,102
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		4		3
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		6		3
Number Of Financing Receivables Total Past Due | loan		19		18
Total		$ 225,866		$ 219,102	200,405	[1]
Financing Receivable, 90 Days or More Past Due, Still Accruing		0		0
Small Business [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		114		111
Small Business [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		116		25
Small Business [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		140		5
Small Business [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		370		141
Small Business [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 225,496		$ 218,961
Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		11		8
Total loans		$ 2,095,644	[1]	$ 2,035,524
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		5		8
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		15		16
Number Of Financing Receivables Total Past Due | loan		31		32
Total		$ 2,095,644		$ 2,035,524	1,706,045	[1]
Financing Receivable, 90 Days or More Past Due, Still Accruing		0		0
Residential Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		2,202		1,654
Residential Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		579		1,105
Residential Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		2,002		1,725
Residential Real Estate [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		4,783		4,484
Residential Real Estate [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 2,090,861		$ 2,031,040
Home Equity Loan [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		18		19
Total loans	[1]	$ 1,090,755
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		3		3
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		18		17
Number Of Financing Receivables Total Past Due | loan		39		39
Total		$ 1,090,755		$ 1,088,750	$ 1,025,815	[1]
Financing Receivable, 90 Days or More Past Due, Still Accruing		23		0
Home Equity Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		1,440		1,647
Home Equity Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		81		201
Home Equity Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans		1,343		965
Home Equity Loan [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		2,864		2,813
Home Equity Loan [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 1,087,891		$ 1,085,937
Consumer - Other [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan	[2]	374		432
Total loans		$ 19,401		$ 35,553
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan	[2]	20		15
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan	[2]	6		4
Number Of Financing Receivables Total Past Due | loan	[2]	400		451
Total	[2]	$ 19,401		$ 35,553
Financing Receivable, 90 Days or More Past Due, Still Accruing	[2]	0		0
Consumer - Other [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans	[2]	353		421
Consumer - Other [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans	[2]	76		83
Consumer - Other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total loans	[2]	45		28
Consumer - Other [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans	[2]	474		532
Consumer - Other [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans	[2]	$ 18,927		$ 35,021

[1] Loan origination dates in the tables above reflect the original origination date, or the date of a material modification of a previously originated loan.

[2] Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances. (2)The amount of net deferred costs on originated loans included in the ending balance was $5.5 million and $5.0 million at March 31, 2023 and December 31, 2022, respectively.