Investment Securities - Non-marketable and Other Securities (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
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Fair value accounting	Dec. 31, 2013 Fair value accounting	Jun. 30, 2014 Fair value accounting Other venture capital investments	Dec. 31, 2013 Fair value accounting Other venture capital investments	Jun. 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	Jun. 30, 2014 Equity method accounting Other investments	Dec. 31, 2013 Equity method accounting Other investments	Jun. 30, 2014 Equity method accounting Low income housing tax credit funds	Dec. 31, 2013 Equity method accounting Low income housing tax credit funds	Jun. 30, 2014 Cost method accounting Other investments	Dec. 31, 2013 Cost method accounting Other investments	Jun. 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	Jun. 30, 2013 Cost method accounting Venture capital and private equity fund investments Investment	Jun. 30, 2014 Upper Limit	Jun. 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	Jun. 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	Jun. 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	Jun. 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	Jun. 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	Jun. 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	Jun. 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	Jun. 30, 2014 SVB Capital—NT Growth Partners, LP Venture capital and private equity fund investments Indirect ownership interest Other investments	Jun. 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	Jun. 30, 2014 SVB Capital Partners II, LP Venture capital and private equity fund investments Direct ownership interest Other investments	Jun. 30, 2014 SVB Capital Partners II, LP Venture capital and private equity fund investments Indirect ownership interest Other investments	Jun. 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	Jun. 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	Jun. 30, 2014 SVB Capital Partners II, LP Fair value accounting Direct ownership interest Other venture capital investments	Jun. 30, 2014 SVB Capital Partners II, LP Fair value accounting Direct ownership interest Venture capital and private equity fund investments	Jun. 30, 2014 SVB Capital Partners II, LP Fair value accounting Indirect ownership interest Other venture capital investments	Jun. 30, 2014 SVB Capital Partners II, LP Fair value accounting Indirect ownership interest Venture capital and private equity fund investments	Jun. 30, 2014 Other private equity fund Venture capital and private equity fund investments Direct ownership interest Other investments	Jun. 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	Jun. 30, 2014 Other private equity fund Fair value accounting Direct ownership interest Venture capital and private equity fund investments	Jun. 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	Jun. 30, 2014 Capital Partners III, LP [Member] Fair value accounting Other venture capital investments	Dec. 31, 2013 Capital Partners III, LP [Member] Fair value accounting Other venture capital investments	Jun. 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	Jun. 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	Jun. 30, 2014 Gold Hill Capital 2008, LP Equity method accounting Direct ownership interest Other investments	Jun. 30, 2014 Gold Hill Capital 2008, LP Equity method accounting Indirect ownership interest Other investments	Jun. 30, 2014 China Joint Venture investment Equity method accounting Other investments	Dec. 31, 2013 China Joint Venture investment Equity method accounting Other investments	Jun. 30, 2014 Other investments Equity method accounting	Dec. 31, 2013 Other investments Equity method accounting	Jun. 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			$ 281,639,000	$ 321,374,000	$ 43,747,000	$ 32,839,000	$ 1,040,522,000	$ 862,972,000											$ 27,075,000	$ 29,104,000	$ 92,617,000	$ 96,185,000	$ 257,489,000	$ 260,272,000	$ 307,600,000	$ 226,729,000	$ 191,024,000	$ 118,181,000	$ 38,879,000	$ 7,944,000	$ 61,573,000	$ 59,028,000		$ 63,026,000	$ 61,126,000			$ 18,471,000	$ 22,684,000	$ 595,000	$ 708,000						$ 644,000	$ 3,695,000		$ 6,177,000	$ 6,564,000	$ 15,000,000	$ 0	$ 4,099,000	$ 3,591,000
Non-marketable securities									137,845,000	142,883,000	95,395,000	72,241,000																																												20,474,000	21,867,000			79,182,000	79,940,000	38,189,000	41,076,000
Non-marketable securities							230,236,000	214,554,000					15,951,000	14,191,000	142,136,000	148,994,000
Total non-marketable and other securities	1,757,235,000	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%	5.10%	5.10%	5.10%	1.30%	1.30%	3.80%	3.80%	41.50%	58.20%	58.20%	41.50%	10.70%	10.70%	0.40%	0.00%	6.80%	6.80%	15.50%	15.50%	11.50%	4.00%	50.00%	50.00%			4.10%
Unrealized gain on one investment	$ 193,900,000
Number of investments															282	288	303
Ownership interest percentage		5.00%																5.00%