Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Remaining Unfunded Commitments to Venture Capital or Private Equity Funds by our Consolidated Managed Funds (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	$ 5,479
Strategic Investors Fund, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	1,338
Capital Preferred Return Fund, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	1,625
Growth Partners, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	$ 2,516