Summary Of Significant Accounting Policies (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013 condition element	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013 condition element	Dec. 31, 2012	Dec. 31, 2011
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Income tax expense	$ 18,755	$ 18,158	$ 20,835	$ 18,922	$ 20,261	$ 19,489	$ 18,312	$ 16,603	$ 76,670	$ 74,665	$ 57,951
Number of grace period days to become non-accrual loans									90 days
Term past due loans places on non-accrual status, days									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, months									6 months
Number of days within a loan being foreclosed is charged off									90 days
Intangible asset useful life									10 years
Holding period before vesting									1 year
Subject to a detailed review									90 days
Minimum [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Minimum Demonstrated Performance Period Troubled Debt Restructurings Returned To Accrual Status									6 months
Maximum [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Minimum Demonstrated Performance Period Troubled Debt Restructurings Returned To Accrual Status									1 year
Immaterial error [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Income tax expense		$ 1,700
Performance Based Restricted Stock Awards [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Vesting period									3 years 0 months
Vesting range, minimum									0.00%
Vesting range, maximum									200.00%
Vesting percentage									50.00%
Long Term Cash Awards [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Number of days prior to the grant date									0 years 0 months 10 days
Long Term Cash Awards [Member] | Minimum [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Vesting period									3 years 0 months
Long Term Cash Awards [Member] | Maximum [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Vesting period									5 years 0 months