Fair Value Measurement (Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012		Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	$ 3,863			$ 3,747
Available for sale, at fair value	2,083,755			2,625,229
Loans held for sale, at fair value	173,994			320,132
Mortgage servicing rights, at fair value	38,192		32,097	27,428		22,513	20,210	18,184
Total assets measured at fair value	2,321,687			3,000,378
Junior subordinated debentures, at fair value	86,159			85,081
Total liabilities measured at fair value	95,160			108,052
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, at fair value	0			0
Total assets measured at fair value	3,058			2,408
Junior subordinated debentures, at fair value	0			0
Total liabilities measured at fair value	0			0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	173,994			320,132
Mortgage servicing rights, at fair value	0			0
Total assets measured at fair value	2,279,799			2,969,046
Junior subordinated debentures, at fair value	0			0
Total liabilities measured at fair value	9,001			22,953
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, at fair value	38,192			27,428
Total assets measured at fair value	38,830			28,924
Junior subordinated debentures, at fair value	86,159			85,081
Total liabilities measured at fair value	86,159			85,099
Obligations Of States And Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	708			1,216
Available for sale, at fair value	242,200			263,725
Obligations Of States And Political Subdivisions [Member] | Level 1 [Member]
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 [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	708			1,216
Available for sale, at fair value	242,200			263,725
Obligations Of States And Political Subdivisions [Member] | Level 3 [Member]
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 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	3,058			2,408
Equity Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	3,058			2,408
Equity Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	0			0
Equity Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	0			0
Other Investments Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	97	[1]		123	[1]
Other Investments Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	0	[1]		0	[1]
Other Investments Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	97	[1]		123	[1]
Other Investments Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading, at fair value	0	[1]		0	[1]
U.S. Treasury And Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	285			45,820
U.S. Treasury And Agencies [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0			0
U.S. Treasury And Agencies [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	285			45,820
U.S. Treasury And Agencies [Member] | Level 3 [Member]
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 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	1,839,028			2,313,376
Residential Mortgage-Backed Securities And Collateralized Mortgage Obligations [Member] | Level 1 [Member]
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 [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	1,839,028			2,313,376
Residential Mortgage-Backed Securities And Collateralized Mortgage Obligations [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0			0
Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	238			222
Other Debt Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0			0
Other Debt Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	238			222
Other Debt Securities [Member] | Level 3 [Member]
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 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	2,004			2,086
Investments In Mutual Funds And Other Equity Securities [Member] | Level 1 [Member]
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 [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	2,004			2,086
Investments In Mutual Funds And Other Equity Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0			0
Interest Rate Lock Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	638			1,496
Derivatives, liabilities	0			18
Interest Rate Lock Commitments [Member] | Level 1 [Member]
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 [Member] | Level 2 [Member]
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 [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	638			1,496
Derivatives, liabilities	0			18
Interest Rate Forward Sales Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	10,347			133
Derivatives, liabilities	108			905
Interest Rate Forward Sales Commitments [Member] | Level 1 [Member]
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 [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	10,347			133
Derivatives, liabilities	108			905
Interest Rate Forward Sales Commitments [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0			0
Derivatives, liabilities	0			0
Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	10,898			22,213
Derivatives, liabilities	8,893			22,048
Interest Rate Swap [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0			0
Derivatives, liabilities	0			0
Interest Rate Swap [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	10,898			22,213
Derivatives, liabilities	8,893			22,048
Interest Rate Swap [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0			0
Derivatives, liabilities	$ 0			$ 0

[1] Principally represents U.S. Treasury and agencies or residential mortgage-backed securities issued or guaranteed by governmental agencies.