Loans And Allowance For Credit Losses (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Accrued Interest Receivable	$ 72,800		$ 71,900
Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Federal Home Loan Bank Debt	3,600,000
Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Federal Reserve Bank Debt	2,900,000
Financing Receivable, Nonaccrual, No Allowance	$ 3,700		4,300
Period after which loans are deemed in default (in days)	90 days
Commitments to lend additional funds to customers with restructured loans	$ 2,400		28,400
Residential mortgage loans held for sale	1,185		1,585
Unpaid Principal Balance on Personal Real Estate Loans Held for Sale	1,100
Student Loans Held for Sale, Lower of Cost or Fair Value	763
HFS Loans on non accrual status	0
HFS loans 90 days past due and still accruing	0
Foreclosed real estate	206		270
Residential Real Estate Acquired Through Foreclosure through Obtaining Physical Possession	206		270
Personal property acquired in repossession	2,000		$ 1,800
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Accrued Interest, Writeoff	94	$ 34
Personal Banking Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Accrued Interest, Writeoff	$ 1,600	$ 1,100