Total Capital Commitments, Unfunded Capital Commitments, and Our Ownership in Each Fund (Footnote Information) (Detail) - Investment	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
SVB Capital Partners II, LP | Fair value accounting | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	0.00%	5.10%
SVB Capital Partners II, LP | Fair value accounting | Direct ownership interest | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	1.30%
SVB Capital Partners II, LP | Fair value accounting | Indirect ownership interest | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	3.80%
Other private equity fund | Fair value accounting | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	58.20%	58.20%
Other private equity fund | Fair value accounting | Direct ownership interest | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	41.50%
Other private equity fund | Fair value accounting | Direct ownership interest | Other investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	41.50%
Other Fund Investments | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Number of other funds with investment commitments	273
Upper Limit | Other Fund Investments | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	5.00%
SVB Capital-NT Growth Partners, LP | Other private equity fund | Fair value accounting | Indirect ownership interest | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	12.60%
SVB Capital Preferred Return Fund, LP | Other private equity fund | Fair value accounting | Indirect ownership interest | Venture capital and private equity fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	4.10%