Allowance For Credit Losses (Progression Of Allowance For Credit Losses Including Allowance For Credit Losses And Reserve For Lending-Related Commitments) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 75,727	$ 75,039	$ 70,010
Provision for credit losses	17,862	17,141	13,773
Financing receivable allowance and provisions for credit losses	93,392	92,027	83,783
Loans charged off	20,555	19,605	25,762
Less recoveries	2,720	3,305	17,018
Net charge-offs	17,835	16,300	8,744
Balance at end of period	$ 75,557	$ 75,727	$ 75,039