Financial Derivatives Schedule of Derivative Instruments, Gain(Loss) in Statement of Financial Performance (Details) (USD $)	3 Months Ended		6 Months Ended				12 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended				6 Months Ended				3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Designated as Hedging Instrument [Member] Interest Rate Swap, Pay Fixed Non-Callable [Member]	Jun. 30, 2013 Not Designated as Hedging Instrument [Member] Interest Rate Swap, Pay Fixed Non-Callable [Member]	Dec. 31, 2012 Not Designated as Hedging Instrument [Member] Interest Rate Swap, Pay Fixed Non-Callable [Member]	Jun. 30, 2013 Non-Interest Income [Member]	Jun. 30, 2012 Non-Interest Income [Member]	Jun. 30, 2013 Non-Interest Income [Member]	Jun. 30, 2012 Non-Interest Income [Member]	Jun. 30, 2013 Non-Interest Income [Member] Designated as Hedging Instrument [Member]		Jun. 30, 2012 Non-Interest Income [Member] Designated as Hedging Instrument [Member]		Jun. 30, 2013 Non-Interest Income [Member] Designated as Hedging Instrument [Member]		Jun. 30, 2012 Non-Interest Income [Member] Designated as Hedging Instrument [Member]		Jun. 30, 2013 Non-Interest Income [Member] Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Jun. 30, 2012 Non-Interest Income [Member] Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Jun. 30, 2013 Non-Interest Income [Member] Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Jun. 30, 2012 Non-Interest Income [Member] Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Credit Default Swap [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Credit Default Swap [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Credit Default Swap [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Credit Default Swap [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Agency Forward [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Agency Forward [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Agency Forward [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Agency Forward [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Treasury Futures [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Treasury Futures [Member]	Jun. 30, 2013 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Treasury Futures [Member]	Jun. 30, 2012 Non-Interest Income [Member] Not Designated as Hedging Instrument [Member] Treasury Futures [Member]
Derivative [Line Items]
Derivative, Weighted-Average Receive Rate					0.27%	0.27%	0.32%
Gain (Loss) on Components Excluded from Assessment of Interest Rate Fair Value Hedge Effectiveness																				$ 3,000,000		$ 6,000,000
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments																				17,535,000	0	23,326,000	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge												(14,729,000)		0		(17,867,000)		0
Gain (Loss) on Fair Value Hedges Recognized in Earnings												2,806,000	[1]	0	[1]	5,459,000	[1]	0	[1]
Gain (Loss) on Derivative Instruments, Net, Pretax																								12,177,000	(31,292,000)	14,018,000	(24,892,000)	10,913,000	(30,187,000)	13,759,000	(23,882,000)	0	(1,000)	0	(76,000)	1,076,000	(809,000)	92,000	(605,000)	188,000	(295,000)	167,000	(329,000)
Gain (loss) on derivatives instruments and hedging activity net pretax	14,983,000	(31,292,000)	19,477,000	(24,892,000)				14,983,000	(31,292,000)	19,477,000	(24,892,000)
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net																				$ (200,000)		$ (500,000)
Derivative, Average Remaining Maturity					3 years 9 months 0 days	3 years 8 months 23 days	4 years 1 month 20 days

[1] Includes gains of $3.0 million and $6.0 million that are excluded from the assessment of hedge effectiveness and losses of $0.2 million and $0.5 million due to hedge ineffectiveness for the three and six months ended June 30, 2013, respectivel