Fair Value Measurement (Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	$ 11,467		$ 10,964
Available for sale, at fair value	3,132,566		2,701,220
Loans held for sale, at fair value	451,350		387,318
Residential mortgage servicing rights, at fair value	141,832	$ 142,344	142,973	$ 112,095	$ 117,172	$ 131,817
Derivatives, assets	42,028		47,501
Total assets measured at fair value	3,779,243		3,289,976
Junior subordinated debentures, at fair value	265,423		262,209
Derivatives, liabilities	5,660		37,063
Total liabilities measured at fair value	271,083		299,272
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	11,410		10,302
Junior subordinated debentures, at fair value	0		0
Total liabilities measured at fair value	0		0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	451,350		387,318
Residential mortgage servicing rights, at fair value	0		0
Total assets measured at fair value	3,621,255		3,132,625
Junior subordinated debentures, at fair value	0		0
Total liabilities measured at fair value	5,660		37,063
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	141,832		142,973
Total assets measured at fair value	146,578		147,049
Junior subordinated debentures, at fair value	265,423		262,209
Total liabilities measured at fair value	265,423		262,209
Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	210		670
Derivatives, liabilities	399		874
Foreign Exchange Contract | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0
Derivatives, liabilities	0		0
Foreign Exchange Contract | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	210		670
Derivatives, liabilities	399		874
Foreign Exchange Contract | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0
Derivatives, liabilities	0		0
Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	4,746		4,076
Interest Rate Lock Commitments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0
Interest Rate Lock Commitments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0
Interest Rate Lock Commitments | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	4,746		4,076
Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,792		8,054
Derivatives, liabilities	913		1,318
Interest Rate Forward Sales Commitments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0
Derivatives, liabilities	0		0
Interest Rate Forward Sales Commitments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,792		8,054
Derivatives, liabilities	913		1,318
Interest Rate Forward Sales Commitments | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0
Derivatives, liabilities	0		0
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	35,280		34,701
Derivatives, liabilities	4,348		34,871
Interest Rate Swap | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0
Derivatives, liabilities	0		0
Interest Rate Swap | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	35,280		34,701
Derivatives, liabilities	4,348		34,871
Interest Rate Swap | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0
Derivatives, liabilities	0		0
Obligations Of States And Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	57		662
Available for sale, at fair value	298,560		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	57		662
Available for sale, at fair value	298,560		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	11,410		10,302
Equity Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	11,410		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	2,832,025		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	2,832,025		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	1,981		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	0		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	1,981		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