Investment Securities - Major Components of Investment Securities Portfolio (Parenthetical) (Detail) (USD $)										3 Months Ended		6 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			6 Months Ended	12 Months Ended
	Jun. 30, 2013 Fair value accounting Other venture capital investments	Dec. 31, 2012 Fair value accounting Other venture capital investments	Jun. 30, 2013 Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 Fair value accounting Venture capital and private equity fund investments		Jun. 30, 2013 Equity method accounting Other investments	Dec. 31, 2012 Equity method accounting Other investments	Jun. 30, 2013 Cost method accounting Other investments	Dec. 31, 2012 Cost method accounting Other investments	Jun. 30, 2013 Cost method accounting Venture capital and private equity fund investments Investment		Jun. 30, 2013 Cost method accounting Venture capital and private equity fund investments Investment		Dec. 31, 2012 Cost method accounting Venture capital and private equity fund investments Investment	Jun. 30, 2013 SVB Strategic Investors Fund, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 SVB Strategic Investors Fund, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2013 SVB Strategic Investors Fund II, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 SVB Strategic Investors Fund II, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2013 SVB Strategic Investors Fund III, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 SVB Strategic Investors Fund III, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2013 SVB Strategic Investors Fund IV, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 SVB Strategic Investors Fund IV, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2013 Strategic Investors Fund V Funds Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 Strategic Investors Fund V Funds Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2013 Strategic Investors Fund VI Limited Partnership Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 Strategic Investors Fund VI Limited Partnership Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2013 SVB Capital Preferred Return Fund, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 SVB Capital Preferred Return Fund, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2013 SVB Capital—NT Growth Partners, LP Fair value accounting Venture capital and private equity fund investments	Dec. 31, 2012 SVB Capital—NT Growth Partners, LP Fair value accounting Venture capital and private equity fund investments	Jun. 30, 2013 SVB Capital Partners II, LP Fair value accounting Other venture capital investments		Dec. 31, 2012 SVB Capital Partners II, LP Fair value accounting Other venture capital investments		Jun. 30, 2013 SVB Capital Partners II, LP Fair value accounting Venture capital and private equity fund investments		Dec. 31, 2012 SVB Capital Partners II, LP Fair value accounting Venture capital and private equity fund investments		Jun. 30, 2013 SVB Capital Partners II, LP Fair value accounting Direct ownership interest Venture capital and private equity fund investments	Jun. 30, 2013 SVB Capital Partners II, LP Fair value accounting Indirect ownership interest Venture capital and private equity fund investments	Jun. 30, 2013 Other private equity fund Fair value accounting Venture capital and private equity fund investments		Dec. 31, 2012 Other private equity fund Fair value accounting Venture capital and private equity fund investments		Jun. 30, 2013 Other private equity fund Fair value accounting Direct ownership interest Venture capital and private equity fund investments	Jun. 30, 2013 Silicon Valley BancVentures, LP Fair value accounting Other venture capital investments	Dec. 31, 2012 Silicon Valley BancVentures, LP Fair value accounting Other venture capital investments	Jun. 30, 2013 SVB Capital Shanghai Yangpu Venture Capital Fund Fair value accounting Other venture capital investments	Dec. 31, 2012 SVB Capital Shanghai Yangpu Venture Capital Fund Fair value accounting Other venture capital investments	Jun. 30, 2013 Gold Hill Venture Lending 03, LP Equity method accounting Other investments		Dec. 31, 2012 Gold Hill Venture Lending 03, LP Equity method accounting Other investments		Jun. 30, 2013 Gold Hill Venture Lending 03, LP Equity method accounting Direct ownership interest Other investments	Jun. 30, 2013 Gold Hill Venture Lending 03, LP Equity method accounting Indirect ownership interest Other investments	Jun. 30, 2013 Gold Hill Capital 2008, LP Equity method accounting Other investments		Dec. 31, 2012 Gold Hill Capital 2008, LP Equity method accounting Other investments		Jun. 30, 2013 Gold Hill Capital 2008, LP Equity method accounting Direct ownership interest Other investments	Jun. 30, 2013 Gold Hill Capital 2008, LP Equity method accounting Indirect ownership interest Other investments	Jun. 30, 2013 China Joint Venture investment Equity method accounting Other investments	Dec. 31, 2012 China Joint Venture investment Equity method accounting Other investments	Jun. 30, 2013 Other investments Equity method accounting	Dec. 31, 2012 Other investments Equity method accounting	Jun. 30, 2013 Upper Limit Cost method accounting Venture capital and private equity fund investments	Dec. 31, 2012 Upper Limit Cost method accounting Venture capital and private equity fund investments	Jun. 30, 2013 Estimated Fair Value Cost method accounting Venture capital and private equity fund investments
Investment Holdings [Line Items]
Non-marketable securities	$ 123,493,000	$ 127,091,000	$ 741,522,000	$ 665,921,000	[1]										$ 32,111,000	$ 32,850,000	$ 93,110,000	$ 91,294,000	$ 223,568,000	$ 209,696,000	$ 198,734,000	$ 169,931,000	$ 69,110,000	$ 40,622,000	$ 1,321,000	$ 0	$ 56,140,000	$ 53,643,000	$ 60,775,000	$ 60,120,000	$ 79,913,000	[2]	$ 79,761,000	[2]	$ 1,098,000	[3]	$ 1,303,000	[3]			$ 5,555,000	[4]	$ 6,462,000	[4]		$ 39,680,000	$ 43,493,000	$ 3,900,000	$ 3,837,000
Percentage of ownership															12.60%	12.60%	8.60%	8.60%	5.90%	5.90%	5.00%	5.00%			0.20%	0.00%	20.00%	20.00%	33.00%	33.00%	5.10%	[2]	5.10%	[2]	5.10%	[3]	5.10%	[3]	1.30%	3.80%	58.20%	[4]	58.20%	[4]	41.50%	10.70%	10.70%	6.80%	6.80%	9.30%	[5]	9.30%	[5]	4.80%	4.50%	15.50%	[6]	15.50%	[6]	11.50%	4.00%	50.00%	50.00%			5.00%	5.00%
Non-marketable securities						144,149,000	139,330,000																																											11,783,000	[5]	9,413,000	[5]			20,260,000	[6]	20,893,000	[6]			80,247,000	78,545,000	31,859,000	30,479,000
Number of investments										303		303		324
Recognized other-than-temporary impairment (OTTI) losses										300,000		800,000
Number of other-than-temporary impaired investments										12		27
Non-marketable securities								$ 18,488,000	$ 19,721,000	$ 156,391,000	[7]	$ 156,391,000	[7]	$ 161,884,000																																																						$ 204,000,000

[1] 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 June 30, 2013 and December 31, 2012 (fair value accounting): June 30, 2013 December 31, 2012(Dollars in thousands) Amount Ownership % Amount Ownership %SVB Strategic Investors Fund, LP $32,111 12.6% $32,850 12.6%SVB Strategic Investors Fund II, LP 93,110 8.6 91,294 8.6SVB Strategic Investors Fund III, LP 223,568 5.9 209,696 5.9SVB Strategic Investors Fund IV, LP 198,734 5.0 169,931 5.0Strategic Investors Fund V Funds 69,110 Various 40,622 VariousStrategic Investors Fund VI Funds 1,321 0.2 — —SVB Capital Preferred Return Fund, LP 56,140 20.0 53,643 20.0SVB Capital—NT Growth Partners, LP 60,775 33.0 60,120 33.0SVB Capital Partners II, LP (i) 1,098 5.1 1,303 5.1Other private equity fund (ii) 5,555 58.2 6,462 58.2Total venture capital and private equity fund investments $741,522 $665,921 (i)At June 30, 2013, 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, 2013, 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] At June 30, 2013, 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] At June 30, 2013, 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 June 30, 2013, 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] At June 30, 2013, 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.

[6] At June 30, 2013, 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.

[7] Represents investments in 303 and 324 funds (primarily venture capital funds) at June 30, 2013 and December 31, 2012, 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. For the three months ended June 30, 2013, we recognized OTTI losses of $0.3 million resulting from other-than-temporary declines in value for 12 of the 303 investments. For the six months ended June 30, 2013, we recognized OTTI losses of $0.8 million resulting from other-than-temporary declines in value for 27 of the 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 investments were temporary and as such, no OTTI was required to be recognized. At June 30, 2013, the carrying value of these venture capital and private equity fund investments (cost method accounting) was $156 million, and the estimated fair value was $204 million.