Commitments and Contingencies (Schedule of Commitments to Extend Credit) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loan Commitments	$ 6,282,932	$ 6,136,313	$ 6,002,231
Commercial Loan
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loan Commitments	3,877,004	3,748,690	3,640,755
Total consumer
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loan Commitments	$ 2,405,928	$ 2,387,623	$ 2,361,476