Loans And Leases (Narrative) (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013 grade	Jun. 30, 2012	Jun. 30, 2013 loan_with_modified_structure grade	Jun. 30, 2012
Loans and Leases Receivable Disclosure [Abstract]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	$ 12,500,000	$ 12,700,000	$ 12,500,000	$ 12,700,000
Amount of loan pledged as collateral	5,500,000,000		5,500,000,000
Loans placed on non-accrual status when past due, days			90 days
Number of days loans past due become subject to detailed review by Company credit risk team			90 days
Interest on non-accrual loans that would have been recorded as additional interest income	5,700,000	3,800,000	8,600,000	7,200,000
Interest income recognized on a cash basis	900,000	400,000	1,800,000	700,000
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	(9,100,000)	(4,500,000)	(14,100,000)	(23,500,000)
Number Of Loans With Two Tier Modified Structure			11
Loans receivable with an A Note / B Note structure			38,500,000
B Notes charged off			17,300,000
A Notes charged off			$ 13,700,000
Number of loans with two tier modified structure in accrual status			8
Number of Grades	10		10