Loans (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended	21 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Sep. 30, 2021	Apr. 01, 2019	Jul. 01, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Business Combination, Acquired Receivables, Gross Contractual Amount							$ 589,700,000	$ 277,900,000
Loans and Leases Receivable, Deferred Income	$ 22,700,000		$ 22,700,000		$ 23,600,000	$ 22,700,000
Impaired Financing Receivable, Related Allowance					5,434,000
Troubled Debt Restructuring Included In Nonaccrual Loans	26,100,000		26,100,000		25,800,000	26,100,000
TDRs included in accruing loan totals	18,800,000		18,800,000		20,900,000	18,800,000
Nonaccrual Trouble Debt Restructuring Current	16,200,000		16,200,000		12,900,000	16,200,000
Commitments to lend additional funds to borrowers whose terms had been modified in a TDR	6,800,000		6,800,000		6,700,000	6,800,000
Specific reserves related to troubled debt restructuring	500,000		500,000		200,000	500,000
Additional Specific Reserves Related To Troubled Debt Restructuring	156,000		174,000	$ 0
Loan Modifications on Nonacrrual status	4,500,000	$ 100,000	$ 6,100,000	400,000
Loan past due period before entering default status			30 days
Financing Receivable, Modifications, Subsequent Default, Recorded Investment, During Period	600,000	700,000	$ 1,000,000	1,600,000
Deposit Liabilities Reclassified as Loans Receivable	4,000,000		4,000,000		2,000,000	4,000,000
PPP loans originated [Line Items]			131,500,000		331,600,000
SBA Fees received					20,200,000
SBA PPP Fees recognized	4,300,000	3,800,000	14,000,000	6,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables							578,600,000	272,800,000
Goodwill, Purchase Accounting Adjustments			4,800,000		7,200,000
Troubled Debt Restructuring, Classification removed	58,000	709,000	4,000,000	1,600,000
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase			52,000
PPP Round 2
Financing Receivable, Credit Quality Indicator [Line Items]
SBA Fees received			12,900,000
Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Impaired Financing Receivable, Related Allowance					1,316,000
PPP loans receivable [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Deferred Income	5,200,000		5,200,000		6,500,000	5,200,000
Accruing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans modified during period	29,000	65,000	29,000	621,000
Nonaccrual [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans modified during period	500,000	700,000	1,000,000	945,000
Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	2,000,000	$ 16,700,000	4,800,000	$ 58,200,000
Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables, COVID Modifications, Recorded Investment, During Period						513,300,000
Consumer Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables, COVID Modifications, Recorded Investment, During Period						79,500,000
Financial Asset Acquired with Credit Deterioration [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Business Combination, Acquired Receivable, Fair Value	$ 8,700,000		$ 8,700,000		$ 11,200,000	$ 8,700,000	18,400,000	4,900,000
Business Combination, Acquired Receivables, Gross Contractual Amount							$ 19,900,000	$ 5,100,000