Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Composition of Loans, Net of Unearned Income (Additional Information) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned income on loans	$ 220,000	$ 163,000
Loans, at amortized cost	36,727,222	33,164,636
Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	280,000	395,000
Construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	147,000	183,000
SVB Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	3,816,277	3,492,269
Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	1,039,456	1,062,264
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	457,234	867,723
Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	4,501,950	4,146,347
Real estate secured loans | SVB Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	3,253,823	3,325,617
Real estate secured loans | SVB Private Bank | Loans for personal residence
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	2,714,069	2,829,880
Real estate secured loans | SVB Private Bank | Loans to eligible employees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	439,006	401,396
Real estate secured loans | SVB Private Bank | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	58,284	55,461
Real estate secured loans | SVB Private Bank | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	42,464	38,880
Real estate secured loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	777,560	820,730
Real estate secured loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	$ 470,567	$ 0