Allowance For Credit Losses (Narrative) (Details)	9 Months Ended		12 Months Ended
	Sep. 30, 2021 USD ($) contract	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Financing Receivable, Impaired [Line Items]
Threshold period for discontinuance of interest accrual	90 days
Financing receivable, nonaccrual, interest income	$ 100,000	$ 100,000
Impaired financing receivable, interest income forgone	$ 300,000	300,000
Financing receivable, threshold period past due	30 days
Allowance for credit losses allocated to troubled debt	$ 300,000		$ 1,600,000
Commitment to lend to troubled debt	0
Increase in provision for credit losses for TDRs	100,000	100,000
Charge-offs related to TDRs	$ 0	$ 0
Number of TDRs that defaulted | contract	1
TDRs, subsequent default	$ 2,100,000		0
Loan restructuring, troubled debt restructuring	21,320,000		$ 26,142,000
Payment Deferral | COVID-19 | Consumer Borrower
Financing Receivable, Impaired [Line Items]
Loan restructuring, trial modifications	143,000,000
Loan restructuring, end of period	3,000,000
Loan restructuring, resumed payment	140,000,000
Loan restructuring, troubled debt restructuring	4,000,000
Payment Deferral | COVID-19 | Commercial Borrower
Financing Receivable, Impaired [Line Items]
Loan restructuring, trial modifications	479,000,000
Loan restructuring, resumed payment	464,000,000
Payment Deferral | COVID-19 | Hotels
Financing Receivable, Impaired [Line Items]
Loan restructuring, end of period	$ 15,000,000
Residential real estate
Financing Receivable, Impaired [Line Items]
Threshold period past due for write-off of financing receivable	120 days
Commercial Industrial Loans And Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Threshold period past due for write-off of financing receivable	120 days
Consumer
Financing Receivable, Impaired [Line Items]
Threshold period past due for write-off of financing receivable	180 days