Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Total Capital Commitments, Unfunded Capital Commitments, and Our Ownership in Each Fund (Additional Information) (Detail) - Venture capital and private equity fund investments - Investment	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Other fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Number of other funds with investment commitments	276
Other fund investments | Upper Limit
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	5.00%
Fair value accounting | SVB Capital Partners II, LP
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership		5.10%
Fair value accounting | Other private equity fund
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	58.20%	58.20%
Fair value accounting | Direct ownership interest | SVB Capital Partners II, LP
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	1.30%
Fair value accounting | Direct ownership interest | Other private equity fund
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	41.50%
Fair value accounting | Indirect ownership interest | SVB Capital Partners II, LP
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	3.80%
Fair value accounting | Indirect ownership interest | Other private equity fund | SVB Capital Preferred Return Fund, LP
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	4.10%
Fair value accounting | Indirect ownership interest | Other private equity fund | SVB Capital—NT Growth Partners, LP
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	12.60%