Composition of Loans, Net of Unearned income (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 8,946,933	[1]	$ 6,970,082	[1]
Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,098,813		879,989
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	829,957		695,138
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	8,116,976		6,274,944
Commercial Portfolio Segment [Member] | Commercial Loans Receivable excluding Construction and Real Estate Secured [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	7,637,721		5,898,700
Consumer Other Financing Receivable | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	144,657		161,137
Real estate secured loans | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	685,300	[2]	534,001	[2]
Software | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	3,261,489		2,492,849
Hardware | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,118,370		952,303
Venture capital/private equity | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,732,699		1,117,419
Life science | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,066,199		863,737
Premium wine | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	557,024		476,233
Premium wine | Commercial Portfolio Segment [Member] | Non-real Estate Secured Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	143,511		130,245
Premium wine | Commercial Portfolio Segment [Member] | Real Estate Secured Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	413,513	[3]	345,988	[3]
Commercial Other Financing Receivable | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	381,195		372,403
Commercial Other Financing Receivable | Commercial Portfolio Segment [Member] | Construction Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	65,742		30,256
Commercial Other Financing Receivable | Commercial Portfolio Segment [Member] | Commercial Loans Receivable excluding Construction and Real Estate Secured [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 315,453		$ 342,147

[1] Included within our total loan portfolio are credit card loans of $64 million and $50 million at December 31, 2012 and 2011, respectively.

[2] Consumer loans secured by real estate at December 31, 2012 and 2011 were comprised of the following:

[3] Included in our premium wine portfolio are gross construction loans of $148 million and $111 million at December 31, 2012 and 2011, respectively.