Derivatives, Derivatives Instruments Gain (Loss) in Income Statement (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	$ 1,103	$ 2,036	$ 2,230	$ 5,330
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	1,225	7,552	(1,348)	6,676
Interest Rate [Member] | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	24	(800)	(2,512)	763
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	0	0	0	0
Energy Commodity [Member] | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	912	2,549	4,399	3,997
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	0	0	0	0
Cattle Commodity [Member] | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	92	203	160	396
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	0	0	0	0
Foreign Exchange [Member] | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	75	84	183	174
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	0	0	0	0
Equity Swap [Member] | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	0	0	0	0
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	0	0	0	0
Total Customer Derivatives | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	1,103	2,036	2,230	5,330
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	0	0	0	0
Interest Rate Risk Management Trading New [Member] | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	0	0	0	0
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	$ 1,225	$ 7,552	$ (1,348)	$ 6,676