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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Junior Subordinated Debentures
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Junior subordinated debentures, at fair value, beginning balance	$ 294,121	$ 278,410	$ 300,870	$ 277,155
Junior subordinated debentures, change included in earnings	4,685	4,283	9,457	8,058
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	(17,240)	1,513	(23,804)	3,196
Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases and Issuances	0	0	0	0
Junior subordinated debentures, at fair value, sales and settlements	(4,538)	(3,537)	(9,495)	(7,740)
Junior subordinated debentures, at fair value, ending balance	277,028	280,669	277,028	280,669
Junior subordinated debentures, at fair value, net change in unrealized gains or (losses) relating to items held at end of period	(12,555)	5,796	(14,347)	11,254
Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Interest rate lock commitment, beginning balance	8,174	5,874	6,757	4,752
Interest rate lock commitment, change included in earnings	1,302	249	2,999	(1,004)
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	6,892	8,099	12,291	14,532
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobserved Inputs Sales And Settlements	(8,219)	(7,440)	(13,898)	(11,498)
Interest rate lock commitment, ending balance	8,149	6,782	8,149	6,782
Interest rate lock commitment, net change in unrealized gains or (losses) relating to items held at end of period	8,149	6,782	8,149	6,782
Mortgage Servicing Rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Mortgage servicing rights, at fair value, beginning balance	158,946	164,760	169,025	153,151
Mortgage servicing rights, at fair value, change included in earnings	(24,658)	(5,403)	(38,624)	(324)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	0	0
Fair value measurement with unobservable inputs reconciliation recurring basis asset purchases and issuances	5,492	6,860	9,379	13,390
Mortgage servicing rights, sales and settlements	0	0	0	0
Mortgage servicing rights, at fair value, ending balance	139,780	166,217	139,780	166,217
Mortgage servicing rights, at fair value, net change in unrealized gains or (losses) relating to items held at end of period	$ (17,753)	$ 500	$ (25,288)	$ 11,777