Derivatives (Derivatives Associated With Interest Rate Risk Management Activities) (Details) - USD ($)		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Term borrowings		$ 1,323,749,000	$ 1,570,646,000	$ 1,312,677,000
Customer Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional		1,822,343,000	1,675,215,000
Assets		87,287,000	83,797,000
Liabilities		935,000	2,241,000
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]	831,958,000	682,318,000
Assets	[1]	39,049,000	30,204,000
Liabilities	[1]	232,000	307,000
Gains/(Losses)	[1]	12,559,000	4,243,000
Offsetting Upstream Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional		1,822,343,000	1,675,215,000
Assets		935,000	2,241,000
Liabilities		87,287,000	83,797,000
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]	831,958,000	682,318,000
Assets	[1]	232,000	307,000
Liabilities	[1]	39,549,000	30,704,000
Gains/(Losses)	[1]	(12,559,000)	(4,243,000)
Interest Rate Swap [Member] | Debt [Member] | Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	[2]	1,150,000,000	1,350,000,000
Assets	[2]	17,852,000	24,368,000
Liabilities	[2]	0	2,677,000
Gains/(Losses)	[2]	17,037,000	970,000
Long Term Debt [Member] | Debt [Member] | Hedged Items [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Term borrowings	[2],[3]	1,150,000,000	1,350,000,000
Gains/(Losses) related to term borrowings	[2],[4]	$ (16,745,000)	$ (923,000)

[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.