Derivative Instruments And Hedging Activities (Schedule Of Notional Amounts And Recorded Gross Fair Values And Related Gain (Loss) Of Derivative Instruments) (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011
Derivative [Line Items]
Total derivatives, Notional amount	$ 3,893,073,000				$ 3,893,073,000				$ 6,063,675,000
Amount of derivative gain (loss), recognized in OCI	95,000		1,653,000		306,000		1,675,000
Amount of derivative gain (loss), Reclassified from AOCI to interest income	3,199,000		9,868,000		8,493,000		23,105,000
Derivatives instruments, Noninterest income (expense)	(6,236,000)		4,860,000		(10,434,000)		6,736,000
Derivatives designated as hedging instruments, Offset to interest expense	756,000		732,000		1,506,000		1,451,000
Reclassification included in OCI					8,493,000		23,105,000
Cash Flow Hedges [Member]
Derivative [Line Items]
Derivatives instruments, Noninterest income (expense)	0		0		0		0
Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	88,399,000				88,399,000				91,955,000
Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	95,007,000				95,007,000				94,773,000
Derivatives Designated As Hedging Instruments [Member]
Derivative [Line Items]
Derivatives designated as hedging instruments, Notional amount	150,000,000				150,000,000				335,000,000
Amount of derivative gain (loss), recognized in OCI	95,000		1,653,000		306,000		1,675,000
Amount of derivative gain (loss), Reclassified from AOCI to interest income	3,199,000		9,868,000		8,493,000		23,105,000
Derivatives instruments, Noninterest income (expense)	0		0		0		0
Derivatives designated as hedging instruments, Offset to interest expense	756,000		732,000		1,506,000		1,451,000
Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Amount of derivative gain (loss), recognized in OCI	95,000		1,653,000		306,000		1,675,000
Amount of derivative gain (loss), Reclassified from AOCI to interest income	3,199,000		9,868,000		8,493,000	[1]	23,105,000	[1]
Derivatives Designated As Hedging Instruments [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	3,617,000				3,617,000				7,341,000
Derivatives Designated As Hedging Instruments [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	0				0				0
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Derivatives designated as hedging instruments, Notional amount	150,000,000	[2]			150,000,000	[2]			335,000,000	[2]
Amount of derivative gain (loss), recognized in OCI	95,000	[2]	1,474,000	[2]	306,000	[2]	1,492,000	[2]
Amount of derivative gain (loss), Reclassified from AOCI to interest income	3,199,000	[2]	8,979,000	[2]	8,493,000	[2]	21,419,000	[2]
Derivatives instruments, Noninterest income (expense)	0		0		0		0
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Assets [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	3,617,000	[2]			3,617,000	[2]			7,341,000	[2]
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	0	[2]			0	[2]			0	[2]
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Floors [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Amount of derivative gain (loss), recognized in OCI			179,000	[2]			183,000	[2]
Amount of derivative gain (loss), Reclassified from AOCI to interest income			889,000	[2]			1,686,000	[2]
Derivatives instruments, Noninterest income (expense)			0				0
Derivatives Designated As Hedging Instruments [Member] | Terminated Swaps On Long-Term Debt [Member] | Fair Value Hedges [Member]
Derivative [Line Items]
Derivatives designated as hedging instruments, Offset to interest expense	756,000		732,000		1,506,000		1,451,000
Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments, Notional amount	3,743,073,000				3,743,073,000				5,728,675,000
Derivatives instruments, Noninterest income (expense)	(6,236,000)		4,860,000		(10,434,000)		6,736,000
Derivatives Not Designated As Hedging Instruments [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	84,782,000				84,782,000				84,614,000
Derivatives Not Designated As Hedging Instruments [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	95,007,000				95,007,000				94,773,000
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments, Notional amount	120,238,000				120,238,000				145,388,000
Derivatives instruments, Noninterest income (expense)	4,000		(13,000)		(128,000)		(76,000)
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	1,463,000				1,463,000				1,952,000
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	1,474,000				1,474,000				1,977,000
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments, Notional amount	2,463,149,000	[3]			2,463,149,000	[3]			2,638,601,000	[3]
Derivatives instruments, Noninterest income (expense)	(804,000)	[3]	(205,000)	[3]	586,000	[3]	1,327,000	[3]
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	83,319,000	[3]			83,319,000	[3]			82,648,000	[3]
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	88,196,000	[3]			88,196,000	[3]			87,363,000	[3]
Derivatives Not Designated As Hedging Instruments [Member] | Energy Commodity Swaps For Customers [Member]
Derivative [Line Items]
Derivatives instruments, Noninterest income (expense)			0				56,000
Derivatives Not Designated As Hedging Instruments [Member] | Basis Swaps [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments, Notional amount	0				0				85,000,000
Derivatives instruments, Noninterest income (expense)	0		62,000		18,000		149,000
Derivatives Not Designated As Hedging Instruments [Member] | Basis Swaps [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	0				0				3,000
Derivatives Not Designated As Hedging Instruments [Member] | Basis Swaps [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	0				0				11,000
Derivatives Not Designated As Hedging Instruments [Member] | Futures Contracts [Member]
Derivative [Line Items]
Derivatives instruments, Noninterest income (expense)	14,000		5,537,000		(10,000)		4,778,000
Derivatives Not Designated As Hedging Instruments [Member] | Options Contracts [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments, Notional amount	0				0				1,700,000,000
Derivatives instruments, Noninterest income (expense)			(521,000)				502,000
Derivatives Not Designated As Hedging Instruments [Member] | Options Contracts [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	0				0				11,000
Derivatives Not Designated As Hedging Instruments [Member] | Options Contracts [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	0				0				0
Derivatives Not Designated As Hedging Instruments [Member] | Total Return Swap [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments, Notional amount	1,159,686,000				1,159,686,000				1,159,686,000
Derivatives instruments, Noninterest income (expense)	(5,450,000)				(10,900,000)
Derivatives Not Designated As Hedging Instruments [Member] | Total Return Swap [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	0				0				0
Derivatives Not Designated As Hedging Instruments [Member] | Total Return Swap [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	$ 5,337,000				$ 5,337,000				$ 5,422,000

[1] Amounts for the six months ended June 30, 2012 and 2011 of $8,493 and $23,105, respectively, are the amounts of reclassification to earnings presented in the tabular changes of AOCI in Note 7.

[2] Amounts recognized in OCI and reclassified from accumulated OCI (“AOCI”) represent the effective portion of the derivative gain (loss).

[3] Amounts include both the customer swaps and the offsetting derivative contracts.