Fair Value Measurement (Schedule Of Reconciliation Of Assets And Liabilities Measured At Fair Value Using Significant Unobservable Inputs (Level 3) On A Recurring Basis) (Details) - Level 3 - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Junior Subordinated Debentures
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Junior subordinated debentures, beginning balance	$ 280,669	$ 265,423	$ 277,155	$ 262,209
Junior subordinated debentures, change included in earnings	4,486	5,043	12,544	14,595
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	2,409	0	5,605	0
Junior subordinated debentures, purchases and issuances	0	0	0	0
Junior subordinated debentures, sales and settlements	(4,718)	(3,591)	(12,458)	(9,929)
Junior subordinated debentures, ending balance	282,846	266,875	282,846	266,875
Junior subordinated debentures, net change in unrealized gains or (losses) relating to items held at end of period	6,895	5,043	18,149	14,595
Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	6,782	4,746	4,752	4,076
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(284)	884	(1,288)	2,261
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobserved Inputs, Purchase And Issuance	4,679	10,028	19,211	31,992
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobserved Inputs Sales And Settlements	(6,018)	(10,877)	(17,516)	(33,548)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	5,159	4,781	5,159	4,781
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease)	5,159	4,781	5,159	4,781
Mortgage Servicing Rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Mortgage servicing rights, beginning balance	166,217	141,832	153,151	142,973
Mortgage servicing rights, change included in earnings	199	(9,233)	(125)	(25,234)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	0	0
Mortgage servicing rights, purchases and issuances	8,622	8,626	22,012	23,486
Mortgage servicing rights, sales and settlements	0	0	0	0
Mortgage servicing rights, ending balance	175,038	141,225	175,038	141,225
Mortgage servicing rights, net change in unrealized gains or (losses) relating to items held at end of period	$ 3,747	$ (4,730)	$ 10,410	$ (12,954)