Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Recorded Investment in Loans Modified in TDRs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	$ 8,724	$ 5,677
Payment deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	8,300	5,700
Principal forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	400
Private equity/venture capital
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0
Investor dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	8,724	677
Investor dependent | Early stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	677
Investor dependent | Mid stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	5,955	0
Investor dependent | Later stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	2,769	0
Cash flow dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	5,000
Cash flow dependent | Sponsor led buyout
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0
Cash flow dependent | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	5,000
SVB Private Bank
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0
Balance sheet dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0
Premium wine
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	$ 0	$ 0