Loans And Allowance For Credit Losses (Narrative) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Line Items]
Accrued Interest Receivable	$ 61,900,000		$ 55,500,000
Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Federal Home Loan Bank Debt	3,300,000,000
Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Federal Reserve Bank Debt	$ 1,300,000,000
Period after which loans are deemed in default (in days)	90 days
Effect on Interest Income Resulting From Modification to Credit Card Loans			(661,000)
Commitments to lend additional funds to customers with restructured loans	$ 532,000		12,600,000
Financing Receivable, Modified, Minimum Term of Payment Deferral for Forbearance and Repayment Plans	3 months
Financing Receivable, Modified, Maximum Term of Payment Deferral for Forbearance and Repayment Plans	30 years
Residential mortgage loans held for sale	$ 684,000		0
Unpaid Principal Balance on Personal Real Estate Loans Held for Sale	666,000
Student Loans Held for Sale, Lower of Cost or Fair Value	5,300,000
HFS Loans on non accrual status	0
HFS loans 90 days past due and still accruing	0
Foreclosed real estate	167,000		96,000
Residential Real Estate Acquired Through Foreclosure through Obtaining Physical Possession	167,000		96,000
Personal property acquired in repossession	1,400,000		1,600,000
Business
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Nonaccrual, No Allowance	3,500,000		$ 3,800,000
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Accrued Interest, Writeoff	34,000	$ 29,000
Personal Banking Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Accrued Interest, Writeoff	1,100,000	$ 899,000
Personal Banking Portfolio Segment [Member] | Consumer credit card
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Modified, Writeoff	$ 25,000