Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Composition of Loans, Net of Unearned Income (Additional Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned income on loans	$ 248,000	$ 226,000
Loans, at amortized cost	47,675,166	45,181,488
Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	461,000	400,000
Construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	108,000	118,000
SVB Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	5,063,827	4,901,056
Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	1,040,223	1,052,643
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	45,688	27,687
Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	5,062,888	4,939,569
Real estate secured loans | SVB Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	4,187,841	4,058,679
Real estate secured loans | SVB Private Bank | Loans for personal residence
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	3,538,077	3,392,237
Real estate secured loans | SVB Private Bank | Loans to eligible employees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	458,736	481,098
Real estate secured loans | SVB Private Bank | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	45,033	42,449
Real estate secured loans | SVB Private Bank | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	145,995	142,895
Real estate secured loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	824,463	824,008
Real estate secured loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	$ 50,584	$ 56,882