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, 2021	Mar. 31, 2020
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	$ 24,252	$ 8,724
Payment deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	22,200	8,300
Principal forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	2,100	400
Investor dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	8,724
Investor dependent | Early stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0
Investor dependent | Mid stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	5,955
Investor dependent | Later stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	2,769
Cash flow dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	22,173	0
Cash flow dependent | Sponsor led buyout
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	18,439	0
Cash flow dependent | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	3,734	0
SVB Private Bank
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	2,079	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
SBA loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0
Global Fund Banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	$ 0	$ 0