Major Components of Investment Securities Portfolio (Parenthetical) (Detail) (USD $)																					6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended		6 Months Ended				12 Months Ended		6 Months Ended			12 Months Ended		6 Months Ended				12 Months Ended		6 Months Ended			12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	1 Months Ended	6 Months Ended				6 Months Ended		12 Months Ended	3 Months Ended	6 Months Ended				6 Months Ended
	Jun. 30, 2012 Fair value accounting Venture capital and private equity fund investments		Dec. 31, 2011 Fair value accounting Venture capital and private equity fund investments		Jun. 30, 2012 Fair value accounting Other venture capital investments		Dec. 31, 2011 Fair value accounting Other venture capital investments		Dec. 31, 2011 Fair value accounting Other investments		Jun. 30, 2012 Equity method accounting Other investments		Dec. 31, 2011 Equity method accounting Other investments		Jun. 30, 2012 Cost method accounting Venture capital and private equity fund investments Investment		Dec. 31, 2011 Cost method accounting Venture capital and private equity fund investments Investment		Jun. 30, 2012 Cost method accounting Other investments	Dec. 31, 2011 Cost method accounting Other investments	Jun. 30, 2012 SVB Capital Partners II, LP Fair value accounting Venture capital and private equity fund investments		Dec. 31, 2011 SVB Capital Partners II, LP Fair value accounting Venture capital and private equity fund investments		Jun. 30, 2012 SVB Capital Partners II, LP Fair value accounting Other venture capital investments		Dec. 31, 2011 SVB Capital Partners II, LP Fair value accounting Other venture capital investments		Jun. 30, 2012 SVB Capital Partners II, LP Fair value accounting Direct ownership interest Venture capital and private equity fund investments	Jun. 30, 2012 SVB Capital Partners II, LP Fair value accounting Indirect ownership interest Venture capital and private equity fund investments	Jun. 30, 2012 Other private equity fund Fair value accounting Venture capital and private equity fund investments		Dec. 31, 2011 Other private equity fund Fair value accounting Venture capital and private equity fund investments		Jun. 30, 2012 Other private equity fund Fair value accounting Direct ownership interest Venture capital and private equity fund investments	Jun. 30, 2012 Gold Hill Venture Lending 03, LP Equity method accounting Other investments		Dec. 31, 2011 Gold Hill Venture Lending 03, LP Equity method accounting Other investments		Jun. 30, 2012 Gold Hill Venture Lending 03, LP Equity method accounting Direct ownership interest Other investments	Jun. 30, 2012 Gold Hill Venture Lending 03, LP Equity method accounting Indirect ownership interest Other investments	Jun. 30, 2012 Gold Hill Capital 2008, LP Equity method accounting Other investments		Dec. 31, 2011 Gold Hill Capital 2008, LP Equity method accounting Other investments		Jun. 30, 2012 Gold Hill Capital 2008, LP Equity method accounting Direct ownership interest Other investments	Jun. 30, 2012 Gold Hill Capital 2008, LP Equity method accounting Indirect ownership interest Other investments	Jun. 30, 2012 SVB Strategic Investors Fund, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2011 SVB Strategic Investors Fund, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2012 SVB Strategic Investors Fund II, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2011 SVB Strategic Investors Fund II, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2012 SVB Strategic Investors Fund III, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2011 SVB Strategic Investors Fund III, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2012 SVB Strategic Investors Fund IV, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2011 SVB Strategic Investors Fund IV, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2012 Strategic Investors Fund V, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2011 Strategic Investors Fund V, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2012 SVB Capital Preferred Return Fund, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2011 SVB Capital Preferred Return Fund, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2012 SVB Capital-NT Growth Partners, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2011 SVB Capital-NT Growth Partners, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2012 Silicon Valley BancVentures, LP Fair value accounting Other venture capital investments	Dec. 31, 2011 Silicon Valley BancVentures, LP Fair value accounting Other venture capital investments	Jun. 30, 2012 SVB India Capital Partners I, LP Fair value accounting Other venture capital investments	Dec. 31, 2011 SVB India Capital Partners I, LP Fair value accounting Other venture capital investments	Jun. 30, 2012 SVB Capital Shanghai Yangpu Venture Capital Fund Fair value accounting Other venture capital investments	Dec. 31, 2011 SVB Capital Shanghai Yangpu Venture Capital Fund Fair value accounting Other venture capital investments	Jun. 30, 2012 Partners for Growth II, LP Equity method accounting Other investments	Dec. 31, 2011 Partners for Growth II, LP Equity method accounting Other investments	May 03, 2012 China Joint Venture Investment Equity method accounting Other investments	Jun. 30, 2012 China Joint Venture Investment Equity method accounting Other investments		Jun. 30, 2012 Other investment Equity method accounting Other investments	Dec. 31, 2011 Other investment Equity method accounting Other investments	Jun. 30, 2012 Lower Limit Partners for Growth, LP Fair value accounting Other investments	Jun. 30, 2012 Upper Limit Cost method accounting Venture capital and private equity fund investments	Dec. 31, 2011 Upper Limit Cost method accounting Venture capital and private equity fund investments	Jun. 30, 2012 Other Than Temporarily Impaired Securities Cost method accounting Venture capital and private equity fund investments Investment	Jun. 30, 2012 Other Than Temporarily Impaired Securities Cost method accounting Venture capital and private equity fund investments Investment	Jun. 30, 2012 Securities Not Related to Other Than Temporary Impairments Cost method accounting Venture capital and private equity fund investments Investment	Jun. 30, 2012 Carrying Amount Cost method accounting Venture capital and private equity fund investments	Jun. 30, 2012 Estimated Fair Value Cost method accounting Venture capital and private equity fund investments	Jun. 30, 2012 SVB Capital-NT Growth Partners, LP Other private equity fund Fair value accounting Indirect ownership interest Venture capital and private equity fund investments	Jun. 30, 2012 SVB Capital Preferred Return Fund, LP Other private equity fund Fair value accounting Indirect ownership interest Venture capital and private equity fund investments
Investment Holdings [Line Items]
Non-marketable securities	$ 639,596,000	[1]	$ 611,824,000	[1]	$ 120,111,000	[2]	$ 124,121,000	[2]	$ 987,000	[3]											$ 863,000	[4]	$ 2,390,000	[4]	$ 59,256,000	[5]	$ 61,099,000	[5]			$ 6,519,000	[6]	$ 11,367,000	[6]														$ 36,694,000	$ 39,567,000	$ 109,343,000	$ 122,619,000	$ 213,405,000	$ 218,429,000	$ 146,477,000	$ 122,076,000	$ 18,134,000	$ 8,838,000	$ 50,573,000	$ 42,580,000	$ 57,588,000	$ 43,958,000	$ 16,739,000	$ 17,878,000	$ 40,668,000	$ 42,832,000	$ 3,448,000	$ 2,312,000
Percentage of ownership																					5.10%	[4]	5.10%	[4]	5.10%	[5]	5.10%	[5]	1.30%	3.80%	58.20%	[6]	58.20%	[6]	41.50%	9.30%	[7]	9.30%	[7]	4.80%	4.50%	15.50%	[8]	15.50%	[8]	11.50%	4.00%	12.60%	12.60%	8.60%	8.60%	5.90%	5.90%	5.00%	5.00%	0.20%	0.30%	20.00%	20.00%	33.00%	33.00%	10.70%	10.70%	14.40%	14.40%	6.80%	6.80%	24.20%	24.20%		50.00%	[9]			50.00%	5.00%	5.00%						12.60%	4.10%
Non-marketable securities											138,993,000	[10]	68,252,000	[10]																						6,238,000	[7]	16,072,000	[7]			19,553,000	[8]	19,328,000	[8]																							3,551,000	3,785,000		79,524,000	[9]	30,127,000	29,067,000
Contribution in joint venture																																																																						79,700,000
Number of investments															326		329
Recognized other-than-temporary impairment ("OTTI") losses																																																																														200,000	500,000
Number of impaired investments																																																																														12	30
Number of investments for which no OTTI was required																																																																																296
Non-marketable securities															$ 153,618,000	[11]	$ 145,007,000	[11]	$ 21,296,000	$ 19,355,000																																																													$ 153,600,000	$ 185,300,000

[1] 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 June 30, 2012 and December 31, 2011: June 30, 2012 December 31, 2011 (Dollars in thousands) Amount Ownership % Amount Ownership % SVB Strategic Investors Fund, LP $ 36,694 12.6 % $ 39,567 12.6 % SVB Strategic Investors Fund II, LP 109,343 8.6 122,619 8.6 SVB Strategic Investors Fund III, LP 213,405 5.9 218,429 5.9 SVB Strategic Investors Fund IV, LP 146,477 5.0 122,076 5.0 Strategic Investors Fund V, LP 18,134 0.2 8,838 0.3 SVB Capital Preferred Return Fund, LP 50,573 20.0 42,580 20.0 SVB Capital-NT Growth Partners, LP 57,588 33.0 43,958 33.0 SVB Capital Partners II, LP (i) 863 5.1 2,390 5.1 Other private equity fund (ii) 6,519 58.2 11,367 58.2 Total venture capital and private equity fund investments $ 639,596 $ 611,824 (i) At June 30, 2012, 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 June 30, 2012, 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.

[2] The following table shows the amount of other venture capital investments by the following consolidated funds and our ownership of each fund at June 30, 2012 and December 31, 2011: June 30, 2012 December 31, 2011 (Dollars in thousands) Amount Ownership % Amount Ownership % Silicon Valley BancVentures, LP $ 16,739 10.7 % $ 17,878 10.7 % SVB Capital Partners II, LP (i) 59,256 5.1 61,099 5.1 SVB India Capital Partners I, LP 40,668 14.4 42,832 14.4 SVB Capital Shanghai Yangpu Venture Capital Fund 3,448 6.8 2,312 6.8 Total other venture capital investments $ 120,111 $ 124,121 (i) At June 30, 2012, 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] Other investments within non-marketable securities (fair value accounting) include our ownership in Partners for Growth, LP, a consolidated debt fund. At June 30, 2012, we had a majority ownership interest of slightly more than 50.0 percent 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.

[4] At June 30, 2012, 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.

[5] At June 30, 2012, 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.

[6] At June 30, 2012, 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] At June 30, 2012, we had a direct ownership interest of 4.8 percent 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 percent. Our aggregate direct and indirect ownership in the fund is 9.3 percent.

[8] At June 30, 2012, 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. Our aggregate direct and indirect ownership in the fund is 15.5 percent.

[9] On May 3, 2012, we contributed $79.7 million to SPD Silicon Valley Bank Co., Ltd., our joint venture bank in China.

[10] The following table shows the carrying value and our ownership percentage of each investment at June 30, 2012 and December 31, 2011: June 30, 2012 December 31, 2011 (Dollars in thousands) Amount Ownership % Amount Ownership % Gold Hill Venture Lending 03, LP (i) $ 6,238 9.3 % $ 16,072 9.3 % Gold Hill Capital 2008, LP (ii) 19,553 15.5 19,328 15.5 Partners for Growth II, LP 3,551 24.2 3,785 24.2 China Joint Venture investment (iii) 79,524 50.0 - - Other investments 30,127 N/A 29,067 N/A Total other investments $ 138,993 $ 68,252 (i) At June 30, 2012, we had a direct ownership interest of 4.8 percent 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 percent. Our aggregate direct and indirect ownership in the fund is 9.3 percent. (ii) At June 30, 2012, 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. Our aggregate direct and indirect ownership in the fund is 15.5 percent. (iii) On May 3, 2012, we contributed $79.7 million to SPD Silicon Valley Bank Co., Ltd., our joint venture bank in China.

[11] Represents investments in 326 and 329 funds (primarily venture capital funds) at June 30, 2012 and December 31, 2011, 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 June 30, 2012, we recognized OTTI losses of $0.2 million resulting from other-than-temporary declines in value for 12 of the 326 investments. For the six months ended June 30, 2012, we recognized OTTI losses of $0.5 million resulting from other-than-temporary declines in value for 30 of the 326 investments. The OTTI losses are included in net gains on investment securities, a component of noninterest income. We concluded that any declines in value for the remaining 296 investments were temporary and as such, no OTTI was required to be recognized. At June 30, 2012, the carrying value of these venture capital and private equity fund investments (cost method accounting) was $153.6 million, and the estimated fair value was $185.3 million.