Loans and Allowance for Loan Losses - Summary of Loans Modified in Troubled Debt Restructurings ("TDRs") by Portfolio Segment and Class of Financing Receivables (Detail) $ in Thousands	9 Months Ended
Sep. 30, 2015 USD ($) troubled_debt_restructuring	Dec. 31, 2014 USD ($)
Financing Receivable, Modifications [Line Items]
Number of loans with concessions granted to borrowers \| troubled_debt_restructuring	13
Unfunded commitments available for funding for modifications (less than)	$ 500
Loans modified in TDRs	91,316	$ 7,151
Life science & healthcare
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	29,529	0
Commercial Portfolio Segment \| Software and internet
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	57,766	3,784
Commercial Portfolio Segment \| Hardware
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	2,301	1,118
Commercial Portfolio Segment \| Premium wine
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	1,202	1,891
Commercial Portfolio Segment \| Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	518	233
Commercial Portfolio Segment \| Commercial loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	91,316	7,026
Consumer Portfolio Segment \| Other consumer loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	0	125
Consumer Portfolio Segment \| Consumer loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	$ 0	$ 125

Total commitments available for funding to clients with financing receivables modified by troubled debt restructurings.

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953676-111524

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The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

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-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554

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