Loans and Allowance for Loan Losses - Composition of Loans, Net of Unearned income (Parenthetical) (Detail) (USD $)	Sep. 30, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 9,824,982,000	[1]	$ 8,946,933,000	[1]
Credit Card Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loan portfolio	85,000,000		64,000,000
Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	831,644,000	[2]	685,300,000	[2]
Real estate secured loans | Loans for personal residence
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	643,345,000		503,378,000
Real estate secured loans | Loans to eligible employees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	119,371,000		110,584,000
Real estate secured loans | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	68,928,000		71,338,000
Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross construction loans	132,000,000		148,000,000
Loans, net of unearned income	641,934,000		557,024,000
Consumer Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 925,569,000		$ 829,957,000

[1] Included within our total loan portfolio are credit card loans of $85 million and $64 million at September 30, 2013 and December 31, 2012, respectively.

[2] Consumer loans secured by real estate at September 30, 2013 and December 31, 2012 were comprised of the following:(Dollars in thousands) September 30, 2013 December 31, 2012Loans for personal residence $643,345 $503,378Loans to eligible employees 119,371 110,584Home equity lines of credit 68,928 71,338Consumer loans secured by real estate $831,644 $685,300