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) $ in Thousands	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Residential mortgage servicing rights, at fair value	$ 105,834	$ 102,699	$ 92,907	$ 93,248	$ 96,356	$ 115,010
Asset Derivatives	210,688		342,510
Junior subordinated debentures, at fair value	299,508		255,217
Residential mortgage servicing rights
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Residential mortgage servicing rights, at fair value	105,834
Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Asset Derivatives	8,258		28,144
Junior subordinated debentures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Junior subordinated debentures, at fair value	299,508
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Residential mortgage servicing rights, at fair value	105,834		92,907
Junior subordinated debentures, at fair value	299,508		255,217
Level 3 | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Asset Derivatives	$ 8,258		$ 28,144
Level 3 | Discounted cash flow | Residential mortgage servicing rights | Weighted Average | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.1621
Level 3 | Discounted cash flow | Residential mortgage servicing rights | Weighted Average | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0969
Level 3 | Discounted cash flow | Residential mortgage servicing rights | Minimum | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0820
Level 3 | Discounted cash flow | Residential mortgage servicing rights | Minimum | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0950
Level 3 | Discounted cash flow | Residential mortgage servicing rights | Maximum | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.7217
Level 3 | Discounted cash flow | Residential mortgage servicing rights | Maximum | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.1250
Level 3 | Discounted cash flow | Junior subordinated debentures | Weighted Average | Credit spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.0346
Level 3 | Discounted cash flow | Junior subordinated debentures | Minimum | Credit spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.0157
Level 3 | Discounted cash flow | Junior subordinated debentures | Maximum | Credit spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.0442
Level 3 | Internal pricing model | Interest rate lock commitments | Weighted Average | Pull-through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.8803
Level 3 | Internal pricing model | Interest rate lock commitments | Minimum | Pull-through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.7000
Level 3 | Internal pricing model | Interest rate lock commitments | Maximum | Pull-through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.0000