Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Summary of Loans Modified in Troubled Debt Restructurings (TDRs) (Details) $ in Thousands	9 Months Ended
Sep. 30, 2019 USD ($) troubled_debt_restructuring	Dec. 31, 2018 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of troubled debt restructurings \| troubled_debt_restructuring	20
Loans modified in TDRs	$ 105,245	$ 83,695
Unfunded commitments available for funding associated with TDRs	3,800
Commercial loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	103,105	83,375
Commercial loans \| Software/internet
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	80,704	58,089
Commercial loans \| Hardware
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	0	9,665
Commercial loans \| Life science/healthcare
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	18,689	12,738
Commercial loans \| Premium wine
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	3,712	2,883
Consumer loans \| Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	$ 2,140	$ 320

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

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Amount of financing receivable modified as troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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-Publisher FASB
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-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18845-111554

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