Loans (Narrative) (Details) - USD ($)	3 Months Ended		12 Months Ended	15 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Mar. 31, 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	$ 28,100,000		$ 23,600,000	$ 28,100,000
Impaired Financing Receivable, Related Allowance			5,434,000
Troubled Debt Restructuring Included In Nonaccrual Loans	23,800,000		25,800,000	23,800,000
TDRs included in accruing loan totals	14,800,000		20,900,000	14,800,000
Nonaccrual Trouble Debt Restructuring Current	13,900,000		12,900,000	13,900,000
Commitments to lend additional funds to borrowers whose terms had been modified in a TDR	10,300,000		6,700,000	10,300,000
Specific reserves related to troubled debt restructuring	300,000		200,000	300,000
Additional Specific Reserves Related To Troubled Debt Restructuring	0	$ 0
Loan Modifications on Nonacrrual status	$ 1,700,000	300,000
Loan past due period before entering default status	30 days
Financing Receivable, Modifications, Subsequent Default, Recorded Investment, During Period	$ 1,000,000.0	5,100,000
Deposit Liabilities Reclassified as Loans Receivable	2,400,000		2,000,000.0	2,400,000
PPP loans originated [Line Items]	387,000,000.0		331,600,000
SBA Fees received			20,200,000
SBA PPP Fees recognized	4,200,000		13,700,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables					578,600,000	272,800,000
Goodwill, Purchase Accounting Adjustments	6,400,000		7,200,000
Troubled Debt Restructuring, Classification removed	3,900,000	0
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	11,400,000
SBA PPP Fees recognized	397,000
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	10,000,000.0		6,500,000	10,000,000.0
Accruing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans modified during period	300,000	4,500,000
Nonaccrual [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans modified during period	700,000	500,000
Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	9,800,000	12,200,000
Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	0	$ 100,000
Financing Receivables, COVID Modifications, Recorded Investment, During Period				573,300,000
Commercial Portfolio Segment [Member] | Covid Restructuring [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables, COVID Modifications, Recorded Investment, During Period				77,000
Commercial Portfolio Segment [Member] | Other Restructuring [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables, COVID Modifications, Recorded Investment, During Period				6,400,000
Consumer Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables, COVID Modifications, Recorded Investment, During Period				96,300,000
Consumer Loan [Member] | Covid Restructuring [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables, COVID Modifications, Recorded Investment, During Period				974,000
Consumer Loan [Member] | Other Restructuring [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables, COVID Modifications, Recorded Investment, During Period	2,100,000
Financial Asset Acquired with Credit Deterioration [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Business Combination, Acquired Receivable, Fair Value	$ 10,300,000		$ 11,200,000	$ 10,300,000	18,400,000	4,900,000
Business Combination, Acquired Receivables, Gross Contractual Amount					$ 19,900,000	$ 5,100,000