Derivatives, Derivatives Instruments Gain (Loss) in Income Statement (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	$ 3,327	$ 3,720	$ 5,600	$ 9,050
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	4,048	4,472	2,700	11,148
Interest Rate [Member] | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	1,709	1,152	(803)	1,915
Derivative Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivatives, Net	0		0	0
Energy Commodity [Member] | Other Operating Revenue [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net	1,360	2,335	5,759	6,332
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	103	133	263	529
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	155	100	381	274
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	3,327	3,720	5,600	9,050
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	$ 4,048	$ 4,472	$ 2,700	$ 11,148