Loans, Allowance for Credit Losses and Credit Quality Financing Receivable Past Due (Details) $ in Thousands		Jun. 30, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan	Jun. 30, 2020 USD ($)
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		264	301
Financing Receivable, 90 Days or More Past Due, Still Accruing		$ 0	$ 1
Loans and Leases Receivable, Gross		$ 8,938,988	$ 9,392,866	$ 9,359,648
Number Of Financing Receivables Total Past Due | loan		325	408
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		11	25
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		50	82
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 3,516	$ 4,168
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		896	9,450
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		5,231	7,778
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		8,929,345	9,371,470
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 9,643	$ 21,396
Commercial And Industrial [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		4	2
Financing Receivable, 90 Days or More Past Due, Still Accruing		$ 0	$ 0
Loans and Leases Receivable, Gross		$ 1,726,498	$ 2,103,152	2,004,645
Number Of Financing Receivables Total Past Due | loan		4	11
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		0	1
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		0	8
Financing Receivable, before Allowance for Credit Loss		$ 1,726,498	$ 2,103,152
Commercial And Industrial [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		1,384	318
Commercial And Industrial [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		0	672
Commercial And Industrial [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		0	785
Commercial And Industrial [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		1,725,114	2,101,377
Commercial And Industrial [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 1,384	$ 1,775
Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		2	3
Financing Receivable, 90 Days or More Past Due, Still Accruing		$ 0	$ 0
Loans and Leases Receivable, Gross		$ 4,251,543	$ 4,173,927	4,071,047
Number Of Financing Receivables Total Past Due | loan		6	7
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		1	0
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		3	4
Financing Receivable, before Allowance for Credit Loss		$ 4,251,543	$ 4,173,927
Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		202	409
Commercial Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		162	0
Commercial Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		291	515
Commercial Real Estate [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		4,250,888	4,173,003
Commercial Real Estate [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 655	$ 924
Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		0	0
Financing Receivable, 90 Days or More Past Due, Still Accruing		$ 0	$ 0
Loans and Leases Receivable, Gross		$ 496,539	$ 553,929	537,788
Number Of Financing Receivables Total Past Due | loan		0	2
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		0	2
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		0	0
Financing Receivable, before Allowance for Credit Loss		$ 496,539	$ 553,929
Construction Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		0	0
Construction Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		0	2,794
Construction Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		0	0
Construction Loans [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		496,539	551,135
Construction Loans [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 0	$ 2,794
Small Business [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		4	14
Financing Receivable, 90 Days or More Past Due, Still Accruing		$ 0	$ 0
Loans and Leases Receivable, Gross		$ 182,863	$ 175,023	170,288
Number Of Financing Receivables Total Past Due | loan		9	24
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		1	6
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		4	4
Financing Receivable, before Allowance for Credit Loss		$ 182,863	$ 175,023
Small Business [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		18	421
Small Business [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		61	273
Small Business [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		32	59
Small Business [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		182,752	174,270
Small Business [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 111	$ 753
Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		9	12
Financing Receivable, 90 Days or More Past Due, Still Accruing		$ 0	$ 0
Loans and Leases Receivable, Gross		$ 1,240,279	$ 1,296,183	$ 1,431,129
Number Of Financing Receivables Total Past Due | loan		33	47
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		2	8
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		22	27
Financing Receivable, before Allowance for Credit Loss		$ 1,240,279	$ 1,296,183
Residential Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		1,167	2,150
Residential Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		153	5,507
Residential Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		3,223	3,648
Residential Real Estate [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		1,235,736	1,284,878
Residential Real Estate [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 4,543	$ 11,305
Home Equity Line of Credit [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan		12	10
Financing Receivable, 90 Days or More Past Due, Still Accruing		$ 0	$ 0
Loans and Leases Receivable, Gross		$ 1,018,408	$ 1,068,790
Number Of Financing Receivables Total Past Due | loan		39	48
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan		7	5
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan		20	33
Home Equity Line of Credit [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 572	$ 733
Home Equity Line of Credit [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		520	203
Home Equity Line of Credit [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		1,684	2,633
Home Equity Line of Credit [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		1,015,632	1,065,221
Home Equity Line of Credit [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 2,776	$ 3,569
Consumer - Other [Member]
Financing Receivable, Past Due [Line Items]
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan	[1]	233	260
Financing Receivable, 90 Days or More Past Due, Still Accruing	[1]	$ 0	$ 1
Loans and Leases Receivable, Gross	[1]	$ 22,858	$ 21,862
Number Of Financing Receivables Total Past Due | loan	[1]	234	269
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan	[1]	0	3
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan	[1]	1	6
Financing Receivable, before Allowance for Credit Loss		$ 22,858	$ 21,862
Consumer - Other [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	[1]	173	137
Consumer - Other [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	[1]	0	1
Consumer - Other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	[1]	1	138
Consumer - Other [Member] | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	[1]	22,684	21,586
Consumer - Other [Member] | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	[1]	$ 174	$ 276

[1] Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances.