Loans And Allowance For Loan Losses (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Loans And Allowance For Loan Losses [Abstract]
Loans pledged at the Federal Home Loan Bank as collateral for borrowings and letters of credit obtained to secure public deposits	$ 3,600,000
Loans Pledged to the Federal Reserve Bank as collateral for discount window borrowings	1,400,000
Troubled Debt Restructured Loans	46,700
Accruing Restructured Loans	29,602	$ 40,313
Restructured Loans NonAccrual	17,100
Restructured commercial loans performing under their modified terms	12,500
Aggregate restructured credit card loans held	8,300
Restructured Loans Due to Bankruptcy Proceeding	$ 8,500
Period after which loans are deemed in default (in days)	90 days
Effect on Interest Income Resulting From Modification to Credit Card Loans	$ (1,000)
Commitments to lend additional funds to customers with restructured loans	1,600
Fair Value of Personal Real Estate Loans Held for Sale	2,200
Unpaid Principal Balance on Personal Real Estate Loans Held for Sale	2,100
Student Loans Held for Sale, Lower of Cost or Fair Value	2,000
Foreclosed real estate	3,100	5,500
Personal property acquired in repossession	$ 3,100	$ 2,400