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		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	$ 26,329	$ 8,566	$ 31,838	$ 73,439
Payment deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	25,600	6,400	30,900	69,400
Principal forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	700	2,200	900	4,000
Global fund banking
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	4,043	8,566	7,699	23,009
Investor dependent | Early stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	4,043	2,205	4,193	2,205
Investor dependent | Mid stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0	209	3,480
Investor dependent | Later stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	6,361	3,297	17,324
Cash flow dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	21,611	0	22,466	48,604
Cash flow dependent | Sponsor led buyout
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	21,611	0	21,611	48,604
Cash flow dependent | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0	855	0
SVB Private Bank
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	0	0	1,826
Balance sheet dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	675	0	675	0
Premium wine
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period	0	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