Derivatives (Derivatives Associated With Interest Rate Risk Management Activities) (Details) (USD $) In Thousands, unless otherwise specified						3 Months Ended						3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Mar. 31, 2012 Customer Interest Rate Contracts [Member]	Mar. 31, 2011 Customer Interest Rate Contracts [Member]	Mar. 31, 2012 Customer Interest Rate Contracts [Member] Customer Interest Rate Contracts Hedging [Member] Hedging Instruments And Hedged Items [Member]		Mar. 31, 2011 Customer 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]	Mar. 31, 2011 Offsetting Upstream Interest Rate Contracts [Member]	Mar. 31, 2012 Offsetting Upstream Interest Rate Contracts [Member] Customer Interest Rate Contracts Hedging [Member] Hedging Instruments And Hedged Items [Member]		Mar. 31, 2011 Offsetting Upstream Interest Rate Contracts [Member] Customer Interest Rate Contracts Hedging [Member] Hedging Instruments And Hedged Items [Member]		Mar. 31, 2012 Interest Rate Swaps [Member] Debt Hedging [Member] Hedging Instruments [Member]		Mar. 31, 2011 Interest Rate Swaps [Member] Debt Hedging [Member] Hedging Instruments [Member]		Mar. 31, 2012 Term Borrowings [Member] Debt Hedging [Member] Hedged Items [Member]		Mar. 31, 2011 Term Borrowings [Member] Debt Hedging [Member] Hedged Items [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional				$ 1,502,356	$ 1,579,996	$ 1,000,992	[1]	$ 1,041,339	[1]	$ 1,502,356	$ 1,579,996	$ 1,000,992	[1]	$ 1,041,339	[1]	$ 1,604,000	[2]	$ 1,604,000	[2]
Assets				113,429	55,979	63,749	[1]	60,827	[1]	2,749	4,968	362	[1]	963	[1]	117,944	[2]	94,205	[2]
Liabilities				2,749	4,968	362	[1]	963	[1]	113,429	55,979	65,449	[1]	63,727	[1]	1,236	[2]	15,897	[2]
Gains/(Losses)						(5,789)	[1]	(10,890)	[1]			6,189	[1]	11,590	[1]	(10,231)	[2]	(19,427)	[2]
Term Borrowings	2,340,706	2,481,660	2,514,754																	1,604,000	[2],[3]	1,604,000	[2],[3]
Gains/(Losses) related to term borrowings																				$ 10,231	[2],[4]	$ 19,427	[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.