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, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned income on loans	$ 169,000	$ 163,000
Loans, at amortized cost	35,968,085	33,164,636
Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	339,000	395,000
Construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	174,000	183,000
SVB Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	3,669,295	3,492,269
Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	1,056,927	1,062,264
Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	3,911,929	4,146,347
Real estate secured loans | SVB Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	3,149,469	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	2,644,842	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	416,287	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	61,749	55,461
Real estate secured loans | SVB Private Bank | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	26,591	38,880
Real estate secured loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at amortized cost	$ 762,460	$ 820,730