Derivatives (Derivatives Associated With Interest Rate Risk Management Activities) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Term borrowings		$ 1,065,651	$ 1,339,940	$ 1,065,651	$ 1,339,940	$ 1,312,677
Customer Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional		1,891,507	1,670,717	1,891,507	1,670,717
Assets		80,800	82,905	80,800	82,905
Liabilities		580	1,512	580	1,512
Customer Interest Rate Contracts [Member] | Customer Interest Rate Contracts Hedging [Member] | Hedging Instruments And Hedged Items [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	[1]	1,204,975	790,321	1,204,975	790,321
Assets	[1]	45,096	34,507	45,096	34,507
Liabilities	[1]	89	210	89	210
Gains/(Losses)	[1]	(1,964)	10,558	18,749	8,643
Offsetting Upstream Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional		1,891,507	1,670,717	1,891,507	1,670,717
Assets		580	1,512	580	1,512
Liabilities		80,800	82,905	80,800	82,905
Offsetting Upstream Interest Rate Contracts [Member] | Customer Interest Rate Contracts Hedging [Member] | Hedging Instruments And Hedged Items [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	[1]	1,204,975	790,321	1,204,975	790,321
Assets	[1]	89	210	89	210
Liabilities	[1]	45,596	35,007	45,596	35,007
Gains/(Losses)	[1]	1,964	(10,558)	(18,749)	(8,643)
Interest Rate Swap [Member] | Debt [Member] | Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	[2]	900,000	1,150,000	900,000	1,150,000
Assets	[2]	17,257	16,960	17,257	16,960
Gains/(Losses)	[2]	(7,254)	3,247	19,352	(6,593)
Long Term Debt [Member] | Debt [Member] | Hedged Items [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Term borrowings	[2],[3]	900,000	1,150,000	900,000	1,150,000
Gains/(Losses) related to term borrowings	[2],[4]	$ 7,152	$ (3,167)	$ (19,059)	$ 6,645

[1] Gains/losses included in the All o ther 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.