Fair Value Measurement (Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	$ 12,255	$ 10,964
Available for sale, at fair value	3,065,769	2,701,220
Loans held for sale, at fair value	259,518	387,318
Residential mortgage servicing rights, at fair value	153,151	142,973	$ 131,817	$ 117,259
Derivatives, assets	32,256	47,501
Total assets measured at fair value	3,522,949	3,289,976
Junior subordinated debentures, at fair value	277,155	262,209
Total liabilities measured at fair value	286,443	299,272
Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	4,752	4,076
Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	286	8,054
Derivatives, liabilities	567	1,318
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	26,081	34,701
Derivatives, liabilities	7,229	34,871
Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,137	670
Derivatives, liabilities	1,492	874
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	0	0
Residential mortgage servicing rights, at fair value	0	0
Total assets measured at fair value	63,952	10,302
Junior subordinated debentures, at fair value	0	0
Total liabilities measured at fair value	0	0
Level 1 | Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0	0
Level 1 | Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0	0
Derivatives, liabilities	0	0
Level 1 | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0	0
Derivatives, liabilities	0	0
Level 1 | Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0	0
Derivatives, liabilities	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	259,518	387,318
Residential mortgage servicing rights, at fair value	0	0
Total assets measured at fair value	3,301,094	3,132,625
Junior subordinated debentures, at fair value	0	0
Total liabilities measured at fair value	9,288	37,063
Level 2 | Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0	0
Level 2 | Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	286	8,054
Derivatives, liabilities	567	1,318
Level 2 | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	26,081	34,701
Derivatives, liabilities	7,229	34,871
Level 2 | Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,137	670
Derivatives, liabilities	1,492	874
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	0	0
Residential mortgage servicing rights, at fair value	153,151	142,973
Total assets measured at fair value	157,903	147,049
Junior subordinated debentures, at fair value	277,155	262,209
Total liabilities measured at fair value	277,155	262,209
Level 3 | Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	4,752	4,076
Level 3 | Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0	0
Derivatives, liabilities	0	0
Level 3 | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0	0
Derivatives, liabilities	0	0
Level 3 | Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0	0
Derivatives, liabilities	0	0
US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	39,698
US Treasury and Government [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0
US Treasury and Government [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	39,698
US Treasury and Government [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0
Obligations Of States And Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	273	662
Available for sale, at fair value	308,456	307,697
Obligations Of States And Political Subdivisions | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	0	0
Available for sale, at fair value	0	0
Obligations Of States And Political Subdivisions | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	273	662
Available for sale, at fair value	308,456	307,697
Obligations Of States And Political Subdivisions | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	0	0
Available for sale, at fair value	0	0
Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	11,982	10,302
Equity Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	11,982	10,302
Equity Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	0	0
Equity Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	0	0
Residential Mortgage-Backed Securities And Collateralized Mortgage Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	2,665,645	2,391,553
Residential Mortgage-Backed Securities And Collateralized Mortgage Obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0	0
Residential Mortgage-Backed Securities And Collateralized Mortgage Obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	2,665,645	2,391,553
Residential Mortgage-Backed Securities And Collateralized Mortgage Obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0	0
Investments In Mutual Funds And Other Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	51,970	1,970
Investments In Mutual Funds And Other Equity Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	51,970	0
Investments In Mutual Funds And Other Equity Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0	1,970
Investments In Mutual Funds And Other Equity Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	$ 0	$ 0