Derivatives (Derivatives Associated With Interest Rate Risk Management Activities) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Term borrowings		$ 1,076,943	$ 1,555,272	$ 1,076,943	$ 1,555,272	$ 1,312,677
Customer Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional		1,877,212	1,640,844	1,877,212	1,640,844
Assets		95,612	66,078	95,612	66,078
Liabilities		473	3,285	473	3,285
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]	906,197	744,167	906,197	744,167
Assets	[1]	47,086	24,148	47,086	24,148
Liabilities	[1]	115	409	115	409
Gains/(Losses)	[1]	8,154	(6,158)	20,713	(1,915)
Offsetting Upstream Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional		1,877,212	1,640,844	1,877,212	1,640,844
Assets		473	3,285	473	3,285
Liabilities		95,612	66,078	95,612	66,078
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]	906,197	744,167	906,197	744,167
Assets	[1]	115	409	115	409
Liabilities	[1]	47,586	24,648	47,586	24,648
Gains/(Losses)	[1]	(8,154)	6,158	(20,713)	1,915
Interest Rate Swap [Member] | Debt [Member] | Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	[2]	900,000	1,350,000	900,000	1,350,000
Assets	[2]	24,511	15,954	24,511	15,954
Liabilities	[2]		5,131		5,131
Gains/(Losses)	[2]	6,660	(10,810)	26,606	(9,840)
Long Term Debt [Member] | Debt [Member] | Hedged Items [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Term borrowings	[2],[3]	900,000	1,350,000	900,000	1,350,000
Gains/(Losses) related to term borrowings	[2],[4]	$ (6,557)	$ 10,735	$ (26,211)	$ 9,812

[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.