Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Summary of Loans Modified in Troubled Debt Restructurings (TDRs) by Portfolio Segment and Class of Financing Receivables (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) troubled_debt_restructuring	Dec. 31, 2018 USD ($) troubled_debt_restructuring
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of TDRs | troubled_debt_restructuring	23	17
Loans modified in TDRs	$ 108,982	$ 83,695
Commercial loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	106,878	83,375
Commercial loans | Software/internet
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	71,136	58,089
Commercial loans | Hardware
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	1,685	9,665
Commercial loans | Life science/healthcare
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	20,600	12,738
Commercial loans | Premium wine
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	13,457	2,883
Consumer loans | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified in TDRs	$ 2,104	$ 320