Loans And Leases (Narrative) (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 D	Sep. 30, 2011	Dec. 31, 2011
Loans and Leases Receivable Disclosure [Abstract]
Net deferred fees and unamortized premiums	$ 15,800,000		$ 15,800,000		$ 20,600,000
Amount of loan pledged as collateral	4,200,000,000		4,200,000,000
Interest income recognized on a cash basis	300,000	400,000	1,000,000	1,500,000
Loans placed on non-accrual status when past due, days			90
Number of days loans past due become subject to detailed review by Company credit risk team			90
Interest on non-accrual loans that would have been recorded as additional interest income	4,700,000	6,600,000	10,600,000	19,900,000
Uncollectible TDRs charged off	10,200,000	8,600,000	33,800,000	15,800,000
Number of loans with an A Note / B Note modified structure			10
Loans receivable with an A Note / B Note structure			35,700,000
B Notes charged off			14,000,000
A Notes charged off			$ 14,000,000