Loans, Allowance for Credit Losses and Credit Quality Textual (Details) - USD ($)	3 Months Ended				9 Months Ended
	Sep. 30, 2022		Sep. 30, 2021		Sep. 30, 2022		Sep. 30, 2021		Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Days To Be Termed As Non Accrual Loans					90 days
Provision for (release of) credit losses	$ 3,000,000		$ (10,000,000)		$ 1,000,000		$ (17,500,000)
Total loans	13,700,350,000				13,700,350,000					$ 13,587,286,000
Interest Receivable	42,700,000		36,700,000		42,700,000		36,700,000
Off-Balance Sheet, Credit Loss, Liability	1,300,000				1,300,000					1,500,000
Loans with active Deferrals	193,300,000				193,300,000					383,100,000
Allowance for Loan and Lease Losses, Write-offs	(741,000)
us-gaap_FinancingReceivableTroubledDebtRestructuringIncreaseDecreaseFromModification	14,300,000
Financing Receivable, after Allowance for Credit Loss	2,347,498,000		1,845,455,000		2,347,498,000		1,845,455,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default	0						0
Financing Receivable, Allowance for Credit Loss	147,313,000	[1]	92,246,000	[1]	147,313,000	[1]	92,246,000	[1]	$ 144,319,000	146,922,000	$ 102,357,000	$ 113,392,000
Loans with active Deferrals	193,300,000				193,300,000					383,100,000
Interest Receivable	42,700,000		36,700,000		42,700,000		36,700,000
Off-Balance Sheet, Credit Loss, Liability	1,300,000				1,300,000					1,500,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default	0						0
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for (release of) credit losses			(1,018,000)		5,723,000		(1,698,000)
Total loans	1,548,349,000				1,548,349,000					1,563,279,000
Allowance for Loan and Lease Losses, Write-offs	0
Financing Receivable, after Allowance for Credit Loss	296,626,000		608,467,000		296,626,000		608,467,000
Financing Receivable, Allowance for Credit Loss	20,169,000	[1]	16,014,000	[1]	20,169,000	[1]	16,014,000	[1]	$ 14,107,000	$ 14,402,000	$ 17,032,000	$ 21,086,000
Commercial And Industrial [Member] | Definite Weakness Loss Unlikely [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, after Allowance for Credit Loss	2,485,000		16,597,000		2,485,000		16,597,000
Loans Insured or Guaranteed by US Government Authorities
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans	$ 11,100,000		$ 383,600,000		$ 11,100,000		$ 383,600,000

[1] Balances of accrued interest receivable excluded from amortized cost and the calculation of allowance for credit losses amounted to $42.7 million and $36.7 million as of September 30, 2022 and September 30, 2021, respectively.