Summary Of Significant Accounting Policies (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013 element condition	Sep. 30, 2012	Sep. 30, 2013 element condition	Sep. 30, 2012
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Immaterial Error Correction	1.7
Income tax expense	$ 18,158	$ 19,489	$ 57,915	$ 54,404
Number of grace period days to become non-accrual loans			90 days
Term past due loans places on non-accrual status			90 days
Number of grace period days to charge-off loans			180 days
Number of allowance for loan and lease loss elements	3		3
Number of TDR conditions	2		2
Minimum period troubled debt restructurings placed on non-accrual status			6 months
Minimum [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Minimum Demonstrated Performance Period Troubled Debt Restructurings Returned To Accrual Status			6 months
Immaterial error [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Income tax expense	$ 1,700