Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Remaining Unfunded Commitments to Venture Capital or Private Equity Funds by our Consolidated Managed Funds (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	$ 557,992
SVB Strategic Investors Fund, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	2,250
SVB Strategic Investors Fund II, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	5,021
SVB Strategic Investors Fund III, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	11,237
SVB Strategic Investors Fund IV, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	32,730
Strategic Investors Fund V Funds
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	123,888
Strategic Investors Fund VI Funds
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	219,750
Strategic Investors Fund VII Funds [Domain]
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	153,919
SVB Capital Preferred Return Fund, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	4,448
SVB Capital—NT Growth Partners, LP
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	4,672
Other private equity fund
Commitments and Contingencies Disclosure [Line Items]
SVBFG Unfunded Commitments	$ 77