Summary of Significant Accounting Policies Significant Accounting Policies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) Locations	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
Accounting Policies [Abstract]
Locations | Locations	275
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained Earnings	$ 2,481,577	$ 3,448,324	$ 3,399,972		$ 3,138,472
Allowance for Credit Loss	150,136	150,044	220,834
Off-Balance Sheet, Credit Loss, Liability	33,120	24,204	38,307
Restricted Cash and Cash Equivalents	6,700	17,400
Cash Held at Federal Reserve Bank	$ 389,100
Amortization period of annual fees on credit card loans, months	12 months
Consumer Loans Charged Down to Fair Value [Line Items]
Delinquency Period Revolving Home Equity Loans Charged Down to Fair Value	180 days
Period past due credit card loans are charged off, days	180 days
Period past due loans are placed on non-accrual, days	90 days
Finite-Lived Intangible Assets [Line Items]
Common stock dividend rate percentage	5.00%
Commercial Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Credit Loss	$ 103,293	97,776	121,549
Off-Balance Sheet, Credit Loss, Liability	31,743	23,271	37,259
Personal Banking Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Credit Loss	46,843	52,268	99,285
Off-Balance Sheet, Credit Loss, Liability	1,377	933	1,048
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained Earnings	$ 31,620	$ 92,493	$ 73,000		$ 201,562
Minimum [Member]
Consumer Loans Charged Down to Fair Value [Line Items]
Consumer loans charged down to fair value, days delinquent	120 days
Maximum [Member]
Consumer Loans Charged Down to Fair Value [Line Items]
Consumer loans charged down to fair value, days delinquent	180 days
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Depreciable lives for asset, years	30 years
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciable lives for asset, years	40 years
Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Depreciable lives for asset, years	10 years
Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Depreciable lives for asset, years	3 years
Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciable lives for asset, years	10 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Depreciable lives for asset, years	10 years
Core Deposits [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	8 years
Core Deposits [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	14 years
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Off-Balance Sheet, Credit Loss, Liability				$ 16,100
Deferred Income Tax Assets, Net				(1,200)
Accounting Standards Update 2016-13 | Commercial Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Credit Loss				(29,700)
Accounting Standards Update 2016-13 | Personal Banking Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Credit Loss				8,700
Accounting Standards Update 2016-13 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained Earnings				$ 3,800