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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	$ 14,323	$ 68,157	$ 22,917	$ 68,773
Payment deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	14,300	66,300	22,500	66,900
Principal forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period		1,900	400	1,900
Private equity/venture capital
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0	0	0
Investor dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	9,340	17,735	17,933	18,351
Investor dependent | Early stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	93	0	93	616
Investor dependent | Mid stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	5,281	3,521	11,130	3,521
Investor dependent | Later stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	3,966	14,214	6,710	14,214
Cash flow dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	3,986	48,557	3,986	48,557
Cash flow dependent | Sponsor led buyout
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	48,557	0	48,557
Cash flow dependent | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	3,986	0	3,986	0
SVB Private Bank
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	1,865	0	1,865
Balance sheet dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0	0	0
Premium wine
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	997	0	998	0
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0	0	0
SBA loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	$ 0	$ 0	$ 0	$ 0