Loans And Allowance For Credit Losses (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Accrued Interest Receivable	$ 32,100,000		$ 25,900,000
Loans pledged at the Federal Home Loan Bank as collateral for borrowings and letters of credit obtained to secure public deposits	3,200,000,000
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	$ (649,000)
Commitments to lend additional funds to customers with restructured loans	17,700,000
Letters of Credit to Customers with Substandard Risk Rating	24,000,000
Residential mortgage loans held for sale	3,901,000		5,570,000
Unpaid Principal Balance on Personal Real Estate Loans Held for Sale	3,900,000
Student Loans Held for Sale, Lower of Cost or Fair Value	5,000,000
HFS Loans on non accrual status	0
HFS loans past due and still accruing	0
Foreclosed real estate	296,000		115,000
Personal property acquired in repossession	1,300,000		1,100,000
Business
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Nonaccrual, No Allowance	4,900,000		$ 5,300,000
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Accrued Interest, Writeoff	29,000	$ 125,000
Personal Banking Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Accrued Interest, Writeoff	$ 899,000	$ 2,000,000