Loans, Allowance for Credit Losses and Credit Quality Textual (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Days To Be Termed As Non Accrual Loans	90 days
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease) by percentage	(5.20%)
Provision for credit losses	$ (2,500,000)	$ 25,000,000
Interest Receivable	33,400,000	25,900,000
Off-Balance Sheet, Credit Loss, Liability	1,000,000.0		$ 1,200,000
Loans with active Deferrals	220,600,000		173,600,000
Allowance for Loan and Lease Losses, Write-offs	(3,686,000)
Financing Receivable, Troubled Debt Restructuring, Increase (Decrease) from Modification		1,106,000
us-gaap_FinancingReceivableTroubledDebtRestructuringIncreaseDecreaseFromModification	14,300,000	872,000,000
Loans with active Deferrals	220,600,000		173,600,000
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method		(1,137,000)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	1,200,000	1,157,000
Interest Receivable	33,400,000	25,900,000
Loans and Leases Receivable, Allowance	(107,549,000)	(92,376,000)	(113,392,000)
Off-Balance Sheet, Credit Loss, Liability	1,000,000.0		1,200,000
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	5,800,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default	0	0
US Government Insured Loan Program [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	340,000,000.0		506,300,000
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for credit losses		5,948,000
Financing Receivable, before Allowance for Credit Loss	2,086,671,000		$ 2,103,152,000
Allowance for Loan and Lease Losses, Write-offs	(3,331,000)
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method		(1,984,000)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase		49,000
Loans and Leases Receivable, Allowance		$ (21,649,000)
Loans Insured or Guaranteed by US Government Authorities
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 846,300,000