Composition of Loans, Net of Unearned income (Detail) (USD $) In Thousands	Sep. 30, 2011		Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 6,328,588		$ 5,521,737
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	5,268,800	[1]	4,594,777	[1]
Commercial loans | Software
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,272,443		1,820,385
Commercial loans | Hardware
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	577,443		561,610
Commercial loans | Clean technology
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	270,582		159,502
Commercial loans | Venture capital/private equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,079,215		1,036,077
Commercial loans | Life science
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	686,722		568,739
Commercial loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	130,983	[2]	144,972	[2]
Commercial loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	251,412		303,492
Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	842,194		673,959
Real estate secured loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	344,714	[2]	312,255	[2]
Real estate secured loans | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	497,480	[3]	361,704	[3]
Other loans | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	182,065		192,823
Other loans | Construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	35,529		60,178
Premium wine | Construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 113,700		$ 119,000

[1] Included within our commercial loans portfolio are business credit card loans to commercial clients. At September 30, 2011 and December 31, 2010, our business credit card loans portfolio totaled $47.4 million and $32.5 million, respectively.

[2] Included in our premium wine portfolio are gross construction loans of $113.7 million and $119.0 million at September 30, 2011 and December 31, 2010, respectively.

[3] Consumer loans secured by real estate at September 30, 2011 and December 31, 2010 were comprised of the following: (Dollars in thousands) September 30, 2011 December 31, 2010 Loans for personal residence $ 326,111 $ 189,039 Loans to eligible employees 93,966 88,510 Home equity lines of credit 77,403 84,155 Consumer loans secured by real estate $ 497,480 $ 361,704