Investment Securities - Non-marketable and Other Securities (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012 Investment
Investment Holdings [Line Items]
Total non-marketable and other securities	$ 1,728,888,000		$ 1,595,494,000
Unrealized Gain (Loss) on Securities	75,000,000
Ownership interest percentage			5.00%
Upper Limit
Investment Holdings [Line Items]
Ownership interest percentage	5.00%
Fair value accounting
Investment Holdings [Line Items]
Non-marketable securities	108,251,000	[1]	321,374,000	[1]
Venture capital and private equity fund investments | Fair value accounting
Investment Holdings [Line Items]
Non-marketable securities	1,130,882,000	[2]	862,972,000	[2]
Non-marketable securities	234,000,000		215,000,000
Venture capital and private equity fund investments | Fair value accounting | SVB Strategic Investors Fund, LP
Investment Holdings [Line Items]
Non-marketable securities	24,645,000		29,104,000
Company Direct and Indirect Ownership in Limited Partnership	12.60%		12.60%
Venture capital and private equity fund investments | Fair value accounting | SVB Strategic Investors Fund II, LP
Investment Holdings [Line Items]
Non-marketable securities	97,250,000		96,185,000
Company Direct and Indirect Ownership in Limited Partnership	8.60%		8.60%
Venture capital and private equity fund investments | Fair value accounting | SVB Strategic Investors Fund III, LP
Investment Holdings [Line Items]
Non-marketable securities	269,821,000		260,272,000
Company Direct and Indirect Ownership in Limited Partnership	5.90%		5.90%
Venture capital and private equity fund investments | Fair value accounting | SVB Strategic Investors Fund IV, LP
Investment Holdings [Line Items]
Non-marketable securities	291,291,000		226,729,000
Company Direct and Indirect Ownership in Limited Partnership	5.00%		5.00%
Venture capital and private equity fund investments | Fair value accounting | Strategic Investors Fund V Funds
Investment Holdings [Line Items]
Non-marketable securities	226,111,000		118,181,000
Venture capital and private equity fund investments | Fair value accounting | Strategic Investors Fund VI Funds
Investment Holdings [Line Items]
Non-marketable securities	89,605,000		7,944,000
Company Direct and Indirect Ownership in Limited Partnership	0.00%		0.20%
Venture capital and private equity fund investments | Fair value accounting | SVB Capital Preferred Return Fund, LP
Investment Holdings [Line Items]
Non-marketable securities	62,110,000		59,028,000
Company Direct and Indirect Ownership in Limited Partnership	20.00%		20.00%
Venture capital and private equity fund investments | Fair value accounting | SVB Capital-NT Growth Partners, LP
Investment Holdings [Line Items]
Non-marketable securities	61,973,000		61,126,000
Company Direct and Indirect Ownership in Limited Partnership	33.00%		33.00%
Venture capital and private equity fund investments | Fair value accounting | SVB Capital Partners II, LP
Investment Holdings [Line Items]
Non-marketable securities	302,000	[3]	708,000	[3]
Company Direct and Indirect Ownership in Limited Partnership	5.10%	[3]	5.10%	[3]
Venture capital and private equity fund investments | Fair value accounting | SVB Capital Partners II, LP | Direct ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	1.30%
Venture capital and private equity fund investments | Fair value accounting | SVB Capital Partners II, LP | Indirect ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	3.80%
Venture capital and private equity fund investments | Fair value accounting | Other private equity fund
Investment Holdings [Line Items]
Non-marketable securities	7,774,000	[4]	3,695,000	[4]
Company Direct and Indirect Ownership in Limited Partnership	58.20%	[4]	58.20%	[4]
Venture capital and private equity fund investments | Fair value accounting | Other private equity fund | Direct ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	41.50%
Venture capital and private equity fund investments | Cost method accounting
Investment Holdings [Line Items]
Non-marketable securities	140,551,000	[5]	148,994,000	[5]
Number of investments	281		288		324
Other venture capital investments | Fair value accounting
Investment Holdings [Line Items]
Non-marketable securities	71,204,000	[6]	32,839,000	[6]
Other venture capital investments | Fair value accounting | SVB Capital Partners II, LP
Investment Holdings [Line Items]
Non-marketable securities	20,481,000	[7]	22,684,000	[7]
Company Direct and Indirect Ownership in Limited Partnership	5.10%	[7]	5.10%	[7]
Other venture capital investments | Fair value accounting | Silicon Valley BancVentures, LP
Investment Holdings [Line Items]
Non-marketable securities	3,291,000		6,564,000
Company Direct and Indirect Ownership in Limited Partnership	10.70%		10.70%
Other venture capital investments | Fair value accounting | Capital Partners III, LP
Investment Holdings [Line Items]
Non-marketable securities	41,055,000		0
Company Direct and Indirect Ownership in Limited Partnership	0.00%		0.00%
Other venture capital investments | Fair value accounting | SVB Capital Shanghai Yangpu Venture Capital Fund
Investment Holdings [Line Items]
Non-marketable securities	6,377,000		3,591,000
Company Direct and Indirect Ownership in Limited Partnership	6.80%		6.80%
Other investments | Venture capital and private equity fund investments | SVB Capital-NT Growth Partners, LP | Indirect ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	12.60%
Other investments | Venture capital and private equity fund investments | SVB Capital Partners II, LP | Direct ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	1.30%
Other investments | Venture capital and private equity fund investments | SVB Capital Partners II, LP | Indirect ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	3.80%
Other investments | Venture capital and private equity fund investments | Other private equity fund | Direct ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	41.50%
Other investments | Venture capital and private equity fund investments | LP and SVB Capital Preferred Return Fund, LP | Indirect ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	4.10%
Other investments | Equity method accounting
Investment Holdings [Line Items]
Non-marketable securities	142,674,000	[8]	142,883,000	[8]
Other investments | Equity method accounting | Gold Hill Capital 2008, LP
Investment Holdings [Line Items]
Non-marketable securities	21,294,000	[9]	21,867,000	[9]
Company Direct and Indirect Ownership in Limited Partnership	15.50%	[9]	15.50%	[9]
Other investments | Equity method accounting | Gold Hill Capital 2008, LP | Direct ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	11.50%
Other investments | Equity method accounting | Gold Hill Capital 2008, LP | Indirect ownership interest
Investment Holdings [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	4.00%
Other investments | Equity method accounting | China Joint Venture investment
Investment Holdings [Line Items]
Non-marketable securities	79,569,000		79,940,000
Company Direct and Indirect Ownership in Limited Partnership	50.00%		50.00%
Other investments | Equity method accounting | Other investments
Investment Holdings [Line Items]
Non-marketable securities	41,811,000		41,076,000
Other investments | Cost method accounting
Investment Holdings [Line Items]
Non-marketable securities	16,676,000		14,191,000
Low income housing tax credit funds | Equity method accounting
Investment Holdings [Line Items]
Non-marketable securities	$ 118,650,000		$ 72,241,000

[1] Investments classified as other securities (fair value accounting) represent direct equity investments in public companies held by our consolidated funds. At December 31, 2014, the amount primarily includes total unrealized gains of $75 million in one public company, FireEye. The extent to which any unrealized gains (or losses) will become realized is subject to a variety of factors, including, among other things, changes in prevailing market prices and the timing of any sales or distribution of securities and may also be constrained by lock-up agreements. None of the FireEye related investments currently are subject to a lock-up agreement.

[2] The following table shows the amounts of venture capital and private equity fund investments held by the following consolidated funds and our ownership percentage of each fund at December 31, 2014 and December 31, 2013 (fair value accounting): December 31, 2014 December 31, 2013(Dollars in thousands) Amount Ownership % Amount Ownership %SVB Strategic Investors Fund, LP $24,645 12.6% $29,104 12.6%SVB Strategic Investors Fund II, LP 97,250 8.6 96,185 8.6SVB Strategic Investors Fund III, LP 269,821 5.9 260,272 5.9SVB Strategic Investors Fund IV, LP 291,291 5.0 226,729 5.0Strategic Investors Fund V Funds 226,111 Various 118,181 VariousStrategic Investors Fund VI Funds 89,605 — 7,944 0.2SVB Capital Preferred Return Fund, LP 62,110 20.0 59,028 20.0SVB Capital—NT Growth Partners, LP 61,973 33.0 61,126 33.0SVB Capital Partners II, LP (i) 302 5.1 708 5.1Other private equity fund (ii) 7,774 58.2 3,695 58.2Total venture capital and private equity fund investments $1,130,882 $862,972 (i)At December 31, 2014, we had a direct ownership interest of 1.3 percent and an indirect ownership interest of 3.8 percent in the fund through our ownership interest of SVB Strategic Investors Fund II, LP.(ii)At December 31, 2014, we had a direct ownership interest of 41.5 percent and indirect ownership interests of 12.6 percent and 4.1 percent in the fund through our ownership interest of SVB Capital—NT Growth Partners, LP and SVB Capital Preferred Return Fund, LP, respectively.

[3] At December 31, 2014, we had a direct ownership interest of 1.3 percent and an indirect ownership interest of 3.8 percent in the fund through our ownership interest of SVB Strategic Investors Fund II, LP.

[4] At December 31, 2014, we had a direct ownership interest of 41.5 percent and indirect ownership interests of 12.6 percent and 4.1 percent in the fund through our ownership interest of SVB Capital—NT Growth Partners, LP and SVB Capital Preferred Return Fund, LP, respectively

[5] Represents investments in 281 and 288 funds (primarily venture capital funds) at December 31, 2014 and December 31, 2013, respectively, where our ownership interest is less than 5% of the voting interests of each such fund and in which we do not have the ability to exercise significant influence over the partnerships operating activities and financial policies. The carrying value, and estimated fair value, of these venture capital and private equity fund investments (cost method accounting) was $141 million, and $234 million, respectively, as of December 31, 2014. The carrying value, and estimated fair value, of the venture capital and private equity fund investments (cost method accounting) was $149 million, and $215 million, respectively, as of December 31, 2013.

[6] The following table shows the amounts of other venture capital investments held by the following consolidated funds and our ownership percentage of each fund at December 31, 2014 and December 31, 2013 (fair value accounting): December 31, 2014 December 31, 2013(Dollars in thousands) Amount Ownership % Amount Ownership %Silicon Valley BancVentures, LP $3,291 10.7% $6,564 10.7%SVB Capital Partners II, LP (i) 20,481 5.1 22,684 5.1Capital Partners III, LP 41,055 — — —SVB Capital Shanghai Yangpu Venture Capital Fund 6,377 6.8 3,591 6.8Total other venture capital investments $71,204 $32,839 (i)At December 31, 2014, we had a direct ownership interest of 1.3 percent and an indirect ownership interest of 3.8 percent in the fund through our ownership of SVB Strategic Investors Fund II, LP.

[7] At December 31, 2014, we had a direct ownership interest of 1.3 percent and an indirect ownership interest of 3.8 percent in the fund through our ownership of SVB Strategic Investors Fund II, LP.

[8] The following table shows the carrying value and our ownership percentage of each investment at December 31, 2014 and December 31, 2013 (equity method accounting): December 31, 2014 December 31, 2013(Dollars in thousands) Amount Ownership % Amount Ownership %Gold Hill Capital 2008, LP (i) $21,294 15.5% $21,867 15.5%China Joint Venture investment 79,569 50.0 79,940 50.0Other investments 41,811 Various 41,076 VariousTotal other investments (equity method accounting) $142,674 $142,883 (i)At December 31, 2014, we had a direct ownership interest of 11.5 percent in the fund and an indirect interest in the fund through our investment in Gold Hill Capital 2008, LLC of 4.0 percent.

[9] At December 31, 2014, we had a direct ownership interest of 11.5 percent in the fund and an indirect interest in the fund through our investment in Gold Hill Capital 2008, LLC of 4.0 percent.