Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Recorded Investment in Loans Modified in TDRs within Previous 12 months Subsequently Defaulted (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	$ 8,247	$ 5,000
Private equity/venture capital
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	0
Investor dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	0
Investor dependent | Early stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	0
Investor dependent | Mid stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	0
Investor dependent | Later stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	0
Cash flow dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	5,000
Cash flow dependent | Sponsor led buyout
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	0
Cash flow dependent | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	5,000
SVB Private Bank
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	0
Balance sheet dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	0	0
Premium wine
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	8,247	0
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment in loans modified in TDRs	$ 0	$ 0