Loans, Allowance for Credit Losses and Credit Quality Financing Receivable, Allowance for Credit Loss (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2021		Sep. 30, 2020		Sep. 30, 2021		Sep. 30, 2020		Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss		$ 92,246	[1]			$ 92,246	[1]			$ 102,357	$ 113,392	$ 112,176	$ 67,740
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[2]							$ (1,137)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[3]							1,157
Allowance for Loan and Lease Losses, Write-offs		(332)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		221
Provision for Loan and Lease Losses		(10,000)
Loans and Leases Receivable, Allowance		92,246	[1]	$ 115,625	[1]	92,246	[1]	115,625	[1]		113,392
Provision for credit losses		(10,000)		7,500		(17,500)		52,500
Allowance for Loan and Lease Loss, Recovery of Bad Debts				253		853		1,113
Allowance for Loan and Lease Losses, Write-offs				(4,304)		(4,499)		(5,748)
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss		16,014	[1]			16,014	[1]			17,032	21,086	25,662	17,594
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[2]							(1,984)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[3]							49
Allowance for Loan and Lease Losses, Write-offs		(1)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		1
Provision for Loan and Lease Losses		(1,018)
Loans and Leases Receivable, Allowance	[1]	16,014		28,219		16,014		28,219
Provision for credit losses				2,741		(1,698)		12,698
Allowance for Loan and Lease Loss, Recovery of Bad Debts				1		100		47
Allowance for Loan and Lease Losses, Write-offs				(185)		(3,474)		(185)
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss		37,798	[1]			37,798	[1]			44,325	45,009	36,956	32,935
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[2]							(13,048)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[3]							337
Allowance for Loan and Lease Losses, Write-offs		0
Allowance for Loan and Lease Loss, Recovery of Bad Debts		0
Provision for Loan and Lease Losses		(6,527)
Loans and Leases Receivable, Allowance	[1]	37,798		39,386		37,798		39,386
Provision for credit losses				6,306		(7,268)		23,038
Allowance for Loan and Lease Loss, Recovery of Bad Debts				9		57		9
Allowance for Loan and Lease Losses, Write-offs				(3,885)		0		(3,885)
Construction Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss		4,468	[1]			4,468	[1]			4,865	5,397	4,501	6,053
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[2]							(3,652)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[3]							0
Allowance for Loan and Lease Losses, Write-offs		0
Allowance for Loan and Lease Loss, Recovery of Bad Debts		0
Provision for Loan and Lease Losses		(397)
Loans and Leases Receivable, Allowance	[1]	4,468		5,210		4,468		5,210
Provision for credit losses				709		(929)		2,809
Allowance for Loan and Lease Loss, Recovery of Bad Debts				0		0		0
Allowance for Loan and Lease Losses, Write-offs				0		0		0
Small Business [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss		3,667	[1]			3,667	[1]			3,612	5,095	4,561	1,746
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[2]							495
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[3]							0
Allowance for Loan and Lease Losses, Write-offs		(83)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		50
Provision for Loan and Lease Losses		88
Loans and Leases Receivable, Allowance	[1]	3,667		4,593		3,667		4,593
Provision for credit losses				79		(1,309)		2,538
Allowance for Loan and Lease Loss, Recovery of Bad Debts				2		65		8
Allowance for Loan and Lease Losses, Write-offs				(49)		(184)		(194)
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss		11,047	[1]			11,047	[1]			12,014	14,275	15,046	3,440
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[2]							9,828
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[3]							423
Allowance for Loan and Lease Losses, Write-offs		0
Allowance for Loan and Lease Loss, Recovery of Bad Debts		0
Provision for Loan and Lease Losses		(967)
Loans and Leases Receivable, Allowance	[1]	11,047		14,163		11,047		14,163
Provision for credit losses				(884)		(3,229)		470
Allowance for Loan and Lease Loss, Recovery of Bad Debts				1		1		2
Allowance for Loan and Lease Losses, Write-offs				0		0		0
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss		18,868	[1]			18,868	[1]			20,087	22,060	24,860	5,576
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[2]							7,012
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[3]							319
Allowance for Loan and Lease Losses, Write-offs		0
Allowance for Loan and Lease Loss, Recovery of Bad Debts		49
Provision for Loan and Lease Losses		(1,268)
Loans and Leases Receivable, Allowance	[1]	18,868		23,572		18,868		23,572
Provision for credit losses				(1,309)		(3,230)		10,633
Allowance for Loan and Lease Loss, Recovery of Bad Debts				21		107		174
Allowance for Loan and Lease Losses, Write-offs				0		(69)		(142)
Consumer - Other [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss		384	[1]			384	[1]			$ 422	$ 470	$ 590	$ 396
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	[2]							212
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	[3]							29
Allowance for Loan and Lease Losses, Write-offs		(248)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		121
Provision for Loan and Lease Losses		89
Loans and Leases Receivable, Allowance	[1]	$ 384		482		384		482
Provision for credit losses				(142)		163		314
Allowance for Loan and Lease Loss, Recovery of Bad Debts				219		523		873
Allowance for Loan and Lease Losses, Write-offs				$ (185)		$ (772)		$ (1,342)

[1] Balances of accrued interest receivable excluded from amortized cost and the calculation of allowance for credit losses amounted to $29.1 million and $36.7 million as of September 30, 2021 and September 30, 2020, respectively.

[2] Represents adjustment needed to reflect the cumulative day one impact pursuant to the Company's adoption of Accounting Standards Update 2016-13. The adjustment represents a $1.1 million decrease to the allowance attributable to the change in accounting methodology for estimating the allowance for credit losses resulting from the Company's adoption of the standard.

[3] Represents adjustment needed to reflect the day one reclassification of the Company's PCI loan balances to PCD and the associated gross-up, pursuant to the Company's adoption of Accounting Standards Update 2016-13. The adjustment represents a $1.2 million increase to the allowance resulting from the day one reclassification.