Fair Value Measurement (Schedule Of A Description Of The Valuation Technique, Unobservable Input, And Qualitative Information For The Company's Assets And Liabilities Classified As Level 3) (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Constant prepayment rate	11.13%	12.27%
Discount rate	9.69%	9.70%
Mortgage Servicing Rights
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation technique	Discounted cash flow
Mortgage Servicing Rights | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Constant prepayment rate	11.13%
Discount rate	9.69%
Interest Rate Lock Commitments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation technique	Internal Pricing Model
Interest Rate Lock Commitments | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull-through rate	88.02%
Junior Subordinated Debentures
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation technique	Discounted cash flow
Junior Subordinated Debentures | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit Spread	4.97%