Investment Securities - Non-marketable and Other Securities (Detail) (USD $)																													9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended		12 Months Ended	9 Months Ended				12 Months Ended		9 Months Ended		12 Months Ended		9 Months Ended					12 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended		12 Months Ended		9 Months Ended			12 Months Ended			9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Fair value accounting		Dec. 31, 2013 Fair value accounting		Sep. 30, 2014 Fair value accounting Other venture capital investments		Dec. 31, 2013 Fair value accounting Other venture capital investments		Sep. 30, 2014 Fair value accounting Venture capital and private equity fund investments		Dec. 31, 2013 Fair value accounting Venture capital and private equity fund investments		Sep. 30, 2014 Equity method accounting Other investments		Dec. 31, 2013 Equity method accounting Other investments		Sep. 30, 2014 Equity method accounting Low income housing tax credit funds	Dec. 31, 2013 Equity method accounting Low income housing tax credit funds	Sep. 30, 2014 Cost method accounting Other investments	Dec. 31, 2013 Cost method accounting Other investments	Sep. 30, 2014 Cost method accounting Venture capital and private equity fund investments Investment		Dec. 31, 2013 Cost method accounting Venture capital and private equity fund investments Investment		Sep. 30, 2013 Cost method accounting Venture capital and private equity fund investments Investment	Sep. 30, 2014 Upper Limit	Sep. 30, 2014 SVB Strategic Investors Fund, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2013 SVB Strategic Investors Fund, LP Fair value accounting Venture capital and private equity fund investments	Sep. 30, 2014 SVB Strategic Investors Fund II, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2013 SVB Strategic Investors Fund II, LP Fair value accounting Venture capital and private equity fund investments	Sep. 30, 2014 SVB Strategic Investors Fund III, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2013 SVB Strategic Investors Fund III, LP Fair value accounting Venture capital and private equity fund investments	Sep. 30, 2014 SVB Strategic Investors Fund IV, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2013 SVB Strategic Investors Fund IV, LP Fair value accounting Venture capital and private equity fund investments	Sep. 30, 2014 Strategic Investors Fund V Funds Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2013 Strategic Investors Fund V Funds Fair value accounting Venture capital and private equity fund investments	Sep. 30, 2014 Strategic Investors Fund VI Funds Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2013 Strategic Investors Fund VI Funds Fair value accounting Venture capital and private equity fund investments	Sep. 30, 2014 SVB Capital Preferred Return Fund, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2013 SVB Capital Preferred Return Fund, LP Fair value accounting Venture capital and private equity fund investments	Sep. 30, 2014 SVB Capital—NT Growth Partners, LP Venture capital and private equity fund investments Indirect ownership interest Other investments	Sep. 30, 2014 SVB Capital—NT Growth Partners, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2013 SVB Capital—NT Growth Partners, LP Fair value accounting Venture capital and private equity fund investments	Sep. 30, 2014 SVB Capital Partners II, LP Venture capital and private equity fund investments Direct ownership interest Other investments	Sep. 30, 2014 SVB Capital Partners II, LP Venture capital and private equity fund investments Indirect ownership interest Other investments	Sep. 30, 2014 SVB Capital Partners II, LP Fair value accounting Other venture capital investments		Dec. 31, 2013 SVB Capital Partners II, LP Fair value accounting Other venture capital investments		Sep. 30, 2014 SVB Capital Partners II, LP Fair value accounting Venture capital and private equity fund investments		Dec. 31, 2013 SVB Capital Partners II, LP Fair value accounting Venture capital and private equity fund investments		Sep. 30, 2014 SVB Capital Partners II, LP Fair value accounting Direct ownership interest Venture capital and private equity fund investments	Sep. 30, 2014 SVB Capital Partners II, LP Fair value accounting Indirect ownership interest Venture capital and private equity fund investments	Sep. 30, 2014 Other private equity fund Venture capital and private equity fund investments Direct ownership interest Other investments	Sep. 30, 2014 Other private equity fund Fair value accounting Venture capital and private equity fund investments		Dec. 31, 2013 Other private equity fund Fair value accounting Venture capital and private equity fund investments		Sep. 30, 2014 Other private equity fund Fair value accounting Direct ownership interest Venture capital and private equity fund investments	Sep. 30, 2014 Silicon Valley BancVentures, LP Fair value accounting Other venture capital investments	Dec. 31, 2013 Silicon Valley BancVentures, LP Fair value accounting Other venture capital investments	Sep. 30, 2014 Capital Partners III, LP Fair value accounting Other venture capital investments	Dec. 31, 2013 Capital Partners III, LP Fair value accounting Other venture capital investments	Sep. 30, 2014 SVB Capital Shanghai Yangpu Venture Capital Fund Fair value accounting Other venture capital investments	Dec. 31, 2013 SVB Capital Shanghai Yangpu Venture Capital Fund Fair value accounting Other venture capital investments	Sep. 30, 2014 Gold Hill Capital 2008, LP Equity method accounting Other investments		Dec. 31, 2013 Gold Hill Capital 2008, LP Equity method accounting Other investments		Sep. 30, 2014 Gold Hill Capital 2008, LP Equity method accounting Direct ownership interest Other investments	Sep. 30, 2014 Gold Hill Capital 2008, LP Equity method accounting Indirect ownership interest Other investments	Sep. 30, 2014 China Joint Venture investment Equity method accounting Other investments	Dec. 31, 2013 China Joint Venture investment Equity method accounting Other investments	Sep. 30, 2014 Other investments Equity method accounting	Dec. 31, 2013 Other investments Equity method accounting	Sep. 30, 2014 LP and SVB Capital Preferred Return Fund, LP Venture capital and private equity fund investments Indirect ownership interest Other investments
Investment Holdings [Line Items]
Non-marketable securities			$ 181,265,000	[1]	$ 321,374,000	[1]	$ 43,863,000	[2]	$ 32,839,000	[2]	$ 1,078,911,000	[3]	$ 862,972,000	[3]															$ 25,625,000	$ 29,104,000	$ 92,681,000	$ 96,185,000	$ 248,816,000	$ 260,272,000	$ 308,332,000	$ 226,729,000	$ 214,863,000	$ 118,181,000	$ 56,958,000	$ 7,944,000	$ 61,876,000	$ 59,028,000		$ 61,818,000	$ 61,126,000			$ 17,802,000	[4]	$ 22,684,000	[4]	$ 302,000	[5]	$ 708,000	[5]				$ 7,640,000	[6]	$ 3,695,000	[6]		$ 5,616,000	$ 6,564,000	$ 15,000,000	$ 0	$ 5,445,000	$ 3,591,000
Non-marketable securities															141,913,000	[7]	142,883,000	[7]	98,417,000	72,241,000																																																		20,685,000	[8]	21,867,000	[8]			79,457,000	79,940,000	41,771,000	41,076,000
Non-marketable securities											240,000,000		215,000,000								16,471,000	14,191,000	142,710,000	[9]	148,994,000	[9]
Total non-marketable and other securities	1,703,550,000	1,595,494,000
Percentage of ownership																													12.60%	12.60%	8.60%	8.60%	5.90%	5.90%	5.00%	5.00%			0.20%	0.20%	20.00%	20.00%	12.60%	33.00%	33.00%	1.30%	3.80%	5.10%	[4]	5.10%	[4]	5.10%	[5]	5.10%	[5]	1.30%	3.80%	41.50%	58.20%	[6]	58.20%	[6]	41.50%	10.70%	10.70%	0.40%	0.00%	6.80%	6.80%	15.50%	[8]	15.50%	[8]	11.50%	4.00%	50.00%	50.00%			4.10%
Unrealized gain on one investment	$ 143,800,000
Number of investments																							281		288		293
Ownership interest percentage		5.00%																										5.00%

[1] Investments classified as other securities (fair value accounting) represent direct equity investments in public companies held by our consolidated funds. At September 30, 2014, the amount primarily includes total unrealized gains of $143.8 million in one public company, FireEye, Inc. ("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, which are subject to our funds' separate discretionary securities sales/distribution and governance processes 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 other venture capital investments held by the following consolidated funds and our ownership percentage of each fund at September 30, 2014 and December 31, 2013 (fair value accounting): September 30, 2014 December 31, 2013(Dollars in thousands) Amount Ownership % Amount Ownership %Silicon Valley BancVentures, LP $5,616 10.7% $6,564 10.7%SVB Capital Partners II, LP (i) 17,802 5.1 22,684 5.1Capital Partners III, LP 15,000 0.4 — —SVB Capital Shanghai Yangpu Venture Capital Fund 5,445 6.8 3,591 6.8Total other venture capital investments $43,863 $32,839 (i)At September 30, 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.

[3] 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 September 30, 2014 and December 31, 2013 (fair value accounting): September 30, 2014 December 31, 2013(Dollars in thousands) Amount Ownership % Amount Ownership %SVB Strategic Investors Fund, LP $25,625 12.6% $29,104 12.6%SVB Strategic Investors Fund II, LP 92,681 8.6 96,185 8.6SVB Strategic Investors Fund III, LP 248,816 5.9 260,272 5.9SVB Strategic Investors Fund IV, LP 308,332 5.0 226,729 5.0Strategic Investors Fund V Funds 214,863 Various 118,181 VariousStrategic Investors Fund VI Funds 56,958 0.2 7,944 0.2SVB Capital Preferred Return Fund, LP 61,876 20.0 59,028 20.0SVB Capital—NT Growth Partners, LP 61,818 33.0 61,126 33.0SVB Capital Partners II, LP (i) 302 5.1 708 5.1Other private equity fund (ii) 7,640 58.2 3,695 58.2Total venture capital and private equity fund investments $1,078,911 $862,972 (i)At September 30, 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 September 30, 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.

[4] At September 30, 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.

[5] At September 30, 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.

[6] At September 30, 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.

[7] The following table shows the carrying value and our ownership percentage of each investment at September 30, 2014 and December 31, 2013 (equity method accounting): September 30, 2014 December 31, 2013(Dollars in thousands) Amount Ownership % Amount Ownership %Gold Hill Capital 2008, LP (i) $20,685 15.5% $21,867 15.5%China Joint Venture investment 79,457 50.0 79,940 50.0Other investments 41,771 Various 41,076 VariousTotal other investments (equity method accounting) $141,913 $142,883 (i)At September 30, 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.

[8] At September 30, 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] Represents investments in 281 and 288 funds (primarily venture capital funds) at September 30, 2014 and December 31, 2013, respectively, where our ownership interest is typically 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 $143 million, and $240 million, respectively, as of September 30, 2014. The carrying value, and estimated fair value, of these venture capital and private equity fund investments (cost method accounting) was $149 million and $215 million, respectively, as of December 31, 2013.