Derivatives (Derivatives Associated With Interest Rate Risk Management Activities) (Details) (USD $) In Thousands, unless otherwise specified						3 Months Ended						3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013 Customer Interest Rate Contracts [Member]	Mar. 31, 2012 Customer Interest Rate Contracts [Member]	Mar. 31, 2013 Customer Interest Rate Contracts [Member] Customer Interest Rate Contracts Hedging [Member] Hedging Instruments And Hedged Items [Member]		Mar. 31, 2012 Customer Interest Rate Contracts [Member] Customer Interest Rate Contracts Hedging [Member] Hedging Instruments And Hedged Items [Member]		Mar. 31, 2013 Offsetting Upstream Interest Rate Contracts [Member]	Mar. 31, 2012 Offsetting Upstream Interest Rate Contracts [Member]	Mar. 31, 2013 Offsetting Upstream Interest Rate Contracts [Member] Customer Interest Rate Contracts Hedging [Member] Hedging Instruments And Hedged Items [Member]		Mar. 31, 2012 Offsetting Upstream Interest Rate Contracts [Member] Customer Interest Rate Contracts Hedging [Member] Hedging Instruments And Hedged Items [Member]		Mar. 31, 2013 Interest Rate Swap [Member] Debt [Member] Hedging Instruments [Member]		Mar. 31, 2012 Interest Rate Swap [Member] Debt [Member] Hedging Instruments [Member]		Mar. 31, 2013 Long Term Debt [Member] Debt [Member] Hedged Items [Member]		Mar. 31, 2012 Long Term Debt [Member] Debt [Member] Hedged Items [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional				$ 1,477,632	$ 1,502,356	$ 925,608	[1]	$ 1,000,992	[1]	$ 1,477,632	$ 1,502,356	$ 925,608	[1]	$ 1,000,992	[1]	$ 1,604,000	[2]	$ 1,604,000	[2]
Assets				119,866	113,429	49,941	[1]	63,749	[1]	1,327	2,749	330	[1]	362	[1]	85,114	[2]	117,944	[2]
Liabilities				1,327	2,749	330	[1]	362	[1]	119,866	113,429	50,741	[1]	65,449	[1]	7,427	[2]	1,236	[2]
Gains/(Losses)						(5,313)	[1]	(5,789)	[1]			5,713	[1]	6,189	[1]	(17,574)	[2]	(10,231)	[2]
Term borrowings	2,197,864	2,226,482	2,340,706																	1,604,000	[2],[3]	1,604,000	[2],[3]
Gains/(Losses) related to term borrowings																				$ 17,574	[2],[4]	$ 10,231	[2],[4]

[1] Gains/losses included in the Other expense section of the Consolidated Condensed Statements of Income.

[2] Gains/losses included in the All other income and commissions section of the Consolidated Condensed Statements of Income.

[3] Represents par value of term borrowings being hedged.

[4] Represents gains and losses attributable to changes in fair value due to interest rate risk as designated in ASC 815-20 hedging relationships.