Major Components of Investment Securities Portfolio (Parenthetical) (Detail) (USD $)	3 Months Ended	9 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	12 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2011 Other Than Temporarily Impaired Securities Cost method accounting Venture capital and private equity fund investments Investment	Sep. 30, 2011 Other Than Temporarily Impaired Securities Cost method accounting Venture capital and private equity fund investments Investment	Sep. 30, 2011 Securities Not Related to Other Than Temporary Impairments Cost method accounting Venture capital and private equity fund investments Investment	Sep. 30, 2011 Carrying Amount Cost method accounting Venture capital and private equity fund investments	Sep. 30, 2011 Estimated Fair Value Cost method accounting Venture capital and private equity fund investments	Sep. 30, 2011 Investment company fair value accounting Direct ownership interest Venture capital and private equity fund investments SVB Capital Partners II, LP	Sep. 30, 2011 Investment company fair value accounting Direct ownership interest Venture capital and private equity fund investments Other private equity fund	Sep. 30, 2011 Investment company fair value accounting Direct ownership interest Other venture capital investments SVB Capital Partners II, LP	Sep. 30, 2011 Equity method accounting Direct ownership interest Other investments Gold Hill Venture Lending 03, LP	Sep. 30, 2011 Equity method accounting Direct ownership interest Other investments Gold Hill Capital 2008, LP	Sep. 30, 2011 Investment company fair value accounting Indirect ownership interest Venture capital and private equity fund investments SVB Capital Preferred Return Fund, LP	Sep. 30, 2011 Investment company fair value accounting Indirect ownership interest Venture capital and private equity fund investments SVB Capital-NT Growth Partners, LP	Sep. 30, 2011 Investment company fair value accounting Indirect ownership interest Venture capital and private equity fund investments SVB Capital Partners II, LP	Sep. 30, 2011 Investment company fair value accounting Indirect ownership interest Other venture capital investments SVB Capital Partners II, LP	Sep. 30, 2011 Equity method accounting Indirect ownership interest Other investments Gold Hill Venture Lending 03, LP	Sep. 30, 2011 Equity method accounting Indirect ownership interest Other investments Gold Hill Capital 2008, LP	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund, LP	Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund, LP	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund II, LP	Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund II, LP	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund III, LP	Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund III, LP	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund IV, LP	Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund IV, LP	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments SVB Strategic Investors Fund V, LP	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments SVB Capital Preferred Return Fund, LP	Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments SVB Capital Preferred Return Fund, LP	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments SVB Capital-NT Growth Partners, LP	Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments SVB Capital-NT Growth Partners, LP	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments SVB Capital Partners II, LP		Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments SVB Capital Partners II, LP		Sep. 30, 2011 Investment company fair value accounting Other venture capital investments SVB Capital Partners II, LP		Dec. 31, 2010 Investment company fair value accounting Other venture capital investments SVB Capital Partners II, LP		Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments Other private equity fund		Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments Other private equity fund		Sep. 30, 2011 Investment company fair value accounting Other venture capital investments Silicon Valley BancVentures, LP	Dec. 31, 2010 Investment company fair value accounting Other venture capital investments Silicon Valley BancVentures, LP	Sep. 30, 2011 Investment company fair value accounting Other venture capital investments SVB India Capital Partners I, LP	Dec. 31, 2010 Investment company fair value accounting Other venture capital investments SVB India Capital Partners I, LP	Sep. 30, 2011 Investment company fair value accounting Other venture capital investments SVB Capital Shanghai Yangpu Venture Capital Fund, LP	Sep. 30, 2011 Investment company fair value accounting Other investments Partners for Growth, LP	Dec. 31, 2010 Investment company fair value accounting Other investments Partners for Growth, LP	Sep. 30, 2011 Equity method accounting Other investments Gold Hill Venture Lending 03, LP		Dec. 31, 2010 Equity method accounting Other investments Gold Hill Venture Lending 03, LP		Sep. 30, 2011 Equity method accounting Other investments Gold Hill Capital 2008, LP		Dec. 31, 2010 Equity method accounting Other investments Gold Hill Capital 2008, LP		Sep. 30, 2011 Equity method accounting Other investments Partners for Growth II, LP	Dec. 31, 2010 Equity method accounting Other investments Partners for Growth II, LP	Sep. 30, 2011 Equity method accounting Other investments Other investment	Dec. 31, 2010 Equity method accounting Other investments Other investment	Sep. 30, 2011 Cost method accounting Venture capital and private equity fund investments Upper Limit	Dec. 31, 2010 Cost method accounting Venture capital and private equity fund investments Upper Limit	Sep. 30, 2011 Investment company fair value accounting Venture capital and private equity fund investments		Dec. 31, 2010 Investment company fair value accounting Venture capital and private equity fund investments		Sep. 30, 2011 Investment company fair value accounting Other venture capital investments		Dec. 31, 2010 Investment company fair value accounting Other venture capital investments		Sep. 30, 2011 Investment company fair value accounting Other investments		Dec. 31, 2010 Investment company fair value accounting Other investments		Sep. 30, 2011 Equity method accounting Other investments		Dec. 31, 2010 Equity method accounting Other investments		Sep. 30, 2011 Cost method accounting Venture capital and private equity fund investments Investment		Dec. 31, 2010 Cost method accounting Venture capital and private equity fund investments Investment		Sep. 30, 2011 Cost method accounting Other venture capital investments	Dec. 31, 2010 Cost method accounting Other venture capital investments
Investment Holdings [Line Items]
Non-marketable securities																	$ 44,205,000	$ 44,722,000	$ 122,264,000	$ 94,694,000	$ 205,505,000	$ 146,613,000	$ 104,114,000	$ 40,639,000	$ 1,965,000	$ 41,432,000	$ 23,071,000	$ 44,837,000	$ 28,624,000	$ 2,324,000	[1]	$ 4,506,000	[1]	$ 60,129,000	[2]	$ 51,545,000	[2]	$ 11,480,000	[3]	$ 8,378,000	[3]	$ 16,606,000	$ 21,371,000	$ 41,927,000	$ 38,927,000	$ 1,498,000																	$ 578,126,000	[4]	$ 391,247,000	[4]	$ 120,160,000	[5]	$ 111,843,000	[5]	$ 973,000	[6]	$ 981,000	[6]
Percentage of ownership						1.30%	41.50%	1.30%	4.80%	11.50%	4.10%	12.60%	3.80%	3.80%	4.50%	4.00%	12.60%	12.60%	8.60%	8.60%	5.90%	5.90%	5.00%	5.00%	0.30%	20.00%	20.00%	33.00%	33.00%	5.10%	[1]	5.10%	[1]	5.10%	[2]	5.10%	[2]	58.20%	[3]	60.60%	[3]	10.70%	10.70%	14.40%	14.40%	6.80%	50.00%	50.00%	9.30%	[7]	9.30%	[7]	15.50%	[8]	15.50%	[8]	24.20%	24.20%			5.00%	5.00%
Non-marketable securities																																																	16,781,000	[7]	17,826,000	[7]	16,414,000	[8]	12,101,000	[8]	3,564,000	10,465,000	29,175,000	26,639,000															65,934,000	[9]	67,031,000	[9]
Number of investments																																																																															329		343
Recognized other-than-temporary impairment ("OTTI") losses	300,000	800,000
Number of impaired investments	21	39
Number of investments for which no OTTI was required			290
Non-marketable securities				$ 139,000,000	$ 155,800,000																																																																										$ 138,960,000	[10]	$ 110,466,000	[10]	$ 13,364,000	$ 12,120,000

[1] At September 30, 2011, we had a direct ownership interest of 1.3% and an indirect ownership interest of 3.8% in the fund through our ownership interest of SVB Strategic Investors Fund II, LP.

[2] At September 30, 2011, we had a direct ownership interest of 1.3% and an indirect ownership interest of 3.8% in the fund through our ownership of SVB Strategic Investors Fund II, LP.

[3] At September 30, 2011, we had a direct ownership interest of 41.5% and indirect ownership interests of 12.6% and 4.1% in the fund through our ownership interests of SVB Capital-NT Growth Partners, LP and SVB Capital Preferred Return Fund, LP, respectively.

[4] The following table shows the amount of venture capital and private equity fund investments by the following consolidated funds and our ownership of each fund at September 30, 2011 and December 31, 2010: September 30, 2011 December 31, 2010 (Dollars in thousands) Amount Ownership % Amount Ownership % SVB Strategic Investors Fund, LP $ 44,205 12.6 % $ 44,722 12.6 % SVB Strategic Investors Fund II, LP 122,264 8.6 94,694 8.6 SVB Strategic Investors Fund III, LP 205,505 5.9 146,613 5.9 SVB Strategic Investors Fund IV, LP 104,114 5.0 40,639 5.0 Strategic Investors Fund V, LP 1,965 0.3 - - SVB Capital Preferred Return Fund, LP 41,432 20.0 23,071 20.0 SVB Capital-NT Growth Partners, LP 44,837 33.0 28,624 33.0 SVB Capital Partners II, LP (i) 2,324 5.1 4,506 5.1 Other private equity fund (ii) 11,480 58.2 8,378 60.6 Total venture capital and private equity fund investments $ 578,126 $ 391,247 (i) At September 30, 2011, we had a direct ownership interest of 1.3% and an indirect ownership interest of 3.8% in the fund through our ownership interest of SVB Strategic Investors Fund II, LP. (ii) At September 30, 2011, we had a direct ownership interest of 41.5% and indirect ownership interests of 12.6% and 4.1% in the fund through our ownership interests of SVB Capital-NT Growth Partners, LP and SVB Capital Preferred Return Fund, LP, respectively.

[5] The following table shows the amount of other venture capital investments by the following consolidated funds and our ownership of each fund at September 30, 2011 and December 31, 2010: September 30, 2011 December 31, 2010 (Dollars in thousands) Amount Ownership % Amount Ownership % Silicon Valley BancVentures, LP $ 16,606 10.7 % $ 21,371 10.7 % SVB Capital Partners II, LP (i) 60,129 5.1 51,545 5.1 SVB India Capital Partners I, LP 41,927 14.4 38,927 14.4 SVB Capital Shanghai Yangpu Venture Capital Fund 1,498 6.8 - - Total other venture capital investments $ 120,160 $ 111,843 (i) At September 30, 2011, we had a direct ownership interest of 1.3% and an indirect ownership interest of 3.8% in the fund through our ownership of SVB Strategic Investors Fund II, LP.

[6] Other investments within non-marketable securities (investment company fair value accounting) include our ownership in Partners for Growth, LP, a consolidated debt fund. At both September 30, 2011 and December 31, 2010, we had a majority ownership interest of slightly more than 50.0% in the fund. Partners for Growth, LP is managed by a third party and we do not have an ownership interest in the general partner of this fund.

[7] At September 30, 2011, we had a direct ownership interest of 4.8% in the fund and an indirect interest in the fund through our investment in Gold Hill Venture Lending Partners 03, LLC ("GHLLC") of 4.5%. Our aggregate direct and indirect ownership in the fund is 9.3%.

[8] At September 30, 2011, we had a direct ownership interest of 11.5% in the fund and an indirect interest in the fund through our investment in Gold Hill Capital 2008, LLC of 4.0%. Our aggregate direct and indirect ownership in the fund is 15.5%.

[9] The following table shows the carrying value and our ownership percentage of each investment at September 30, 2011 and December 31, 2010: September 30, 2011 December 31, 2010 (Dollars in thousands) Amount Ownership % Amount Ownership % Gold Hill Venture Lending 03, LP (i) $ 16,781 9.3 % $ 17,826 9.3 % Gold Hill Capital 2008, LP (ii) 16,414 15.5 12,101 15.5 Partners for Growth II, LP 3,564 24.2 10,465 24.2 Other investments 29,175 N/A 26,639 N/A Total other investments $ 65,934 $ 67,031 (i) At September 30, 2011, we had a direct ownership interest of 4.8% in the fund and an indirect interest in the fund through our investment in Gold Hill Venture Lending Partners 03, LLC ("GHLLC") of 4.5%. Our aggregate direct and indirect ownership in the fund is 9.3%. (ii) At September 30, 2011, we had a direct ownership interest of 11.5% in the fund and an indirect interest in the fund through our investment in Gold Hill Capital 2008, LLC of 4.0%. Our aggregate direct and indirect ownership in the fund is 15.5%.

[10] Represents investments in 329 and 343 funds (primarily venture capital funds) at September 30, 2011 and December 31, 2010, 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 and financial policies. For the three months ended September 30, 2011, we recognized other-than-temporary impairment ("OTTI") losses of $0 million resulting from other-than-temporary declines in value for 0 of the 0 investments. For the nine months ended September 30, 2011, we recognized OTTI losses of $0 million resulting from other-than-temporary declines in value for 0 of the 0 investments. The OTTI losses are included in net gains on investment securities, a component of noninterest income. For the remaining 0 investments at September 30, 2011, we concluded that declines in value, if any, were temporary and as such, no OTTI was required to be recognized. At September 30, 2011, the carrying value of these venture capital and private equity fund investments (cost method accounting) was $0 million, and the estimated fair value was $0 million.