Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Recorded Investment in Loans Modified in TDRs (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	$ 2,000,000	$ 14,000,000	$ 17,000,000	$ 23,000,000
Payment deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	1,000,000	14,000,000	14,000,000	23,000,000
Principal forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	1,000,000	0	3,000,000	1,000,000
Investor dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	1,000,000	9,000,000	1,000,000	18,000,000
Investor dependent | Early stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	1,000,000	0	1,000,000	0
Investor dependent | Mid stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	0	5,000,000	0	11,000,000
Investor dependent | Later stage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	0	4,000,000	0	7,000,000
Cash flow dependent
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	0	4,000,000	13,000,000	4,000,000
Cash flow dependent | Sponsor led buyout
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	0	0	13,000,000	0
Cash flow dependent | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	0	4,000,000	0	4,000,000
Private bank
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	1,000,000	0	3,000,000	0
Premium wine
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs during the period (less than for six months ended June 30, 2020 for forgiveness of principal)	$ 0	$ 1,000,000	$ 0	$ 1,000,000