Summary of Significant Accounting Policies - Summary of Ownership Interests in Investments Held Under Fair Value Accounting (Detail) - Fair value accounting	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Venture capital and private equity fund investments | SVB Strategic Investors Fund, LP
Schedule of Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	12.60%	12.60%
Venture capital and private equity fund investments | SVB Capital Preferred Return Fund, LP
Schedule of Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	20.00%	20.00%
Venture capital and private equity fund investments | SVB Capital-NT Growth Partners, LP
Schedule of Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	33.00%	33.00%
Venture capital and private equity fund investments | Other private equity fund
Schedule of Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	58.20%	58.20%
Other venture capital investments | Silicon Valley BancVentures, LP
Schedule of Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	10.70%	10.70%