Loans And Allowance For Loan Losses (Narrative) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 168,370,000				$ 197,757,000				$ 168,370,000	$ 197,757,000
Loans and leases receivable, impaired, interest lost on nonaccrual loans									10,500,000	12,600,000
Interest income recognized									9,522,000	14,861,000
Average recorded investment in impaired loans									358,254,000	622,046,000	$ 952,300,000
Accrued interest income recognized											21,100,000
Investments income recognized in impairment loans, excluding TDRs									0	0	0
Accruing troubled debt restructuring	223,900,000				348,400,000				223,900,000	348,400,000	556,400,000
Provision for losses on loans	$ 5,021,000	$ 2,956,000	$ 6,636,000	$ 4,397,000	$ 8,193,000	$ 3,843,000	$ 12,284,000	$ 9,511,000	19,010,000	33,831,000	$ 69,598,000
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial-type impaired loans									1,000,000
Interest Income Recorded [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income recognized									$ 4,300,000	4,100,000
Loss And Charged Off [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retail loan charge-off period (in days)									120 days
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retail loan substandard period (in days)									90 days
Accruing TDRs With Modifications And Renewals Completed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for losses on loans									$ 12,600,000	$ 21,000,000