Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 10,536,046		$ 7,917,967
Derivatives designated as hedging instruments | Interest rate risks | Interest rate swaps | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	11,441		52,017
Derivatives not designated as hedging instruments | Other derivative instruments | Equity Warrant Asset | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	66,953		47,565
Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	178,693
Fair value accounting | Venture capital and private equity fund investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	611,824	[1]	391,247	[1]
Fair value accounting | Other venture capital investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	124,121	[2]	111,843	[2]
Fair value accounting | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	987	[3]	981	[3]
U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	25,964		26,410
U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,874,932		2,835,093
Residential mortgage-backed securities | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,564,286		1,248,510
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	3,373,760		830,466
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,413,378		2,879,525
Municipal bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	100,498		97,580
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,535		383
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	10,536,046		7,917,967
Other assets - marketable securities	1,410		9,268
Total assets	11,372,081	[4]	8,546,528	[5]
Total liabilities	16,868		10,267
Fair Value, Measurements, Recurring | Derivatives designated as hedging instruments | Interest rate risks | Interest rate swaps | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	11,441		52,017
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	52
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Currency exchange risks | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	18,326		11,349
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Currency exchange risks | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	16,816		10,267
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Other derivative instruments | Equity Warrant Asset | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	66,953		47,565
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Other derivative instruments | Loan conversion options | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	923		4,291
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Other derivative instruments | Client interest rate derivatives | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	50
Fair Value, Measurements, Recurring | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	178,693
Fair Value, Measurements, Recurring | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	736,932		504,071
Fair Value, Measurements, Recurring | Fair value accounting | Venture capital and private equity fund investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	611,824		391,247
Fair Value, Measurements, Recurring | Fair value accounting | Other venture capital investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	124,121		111,843
Fair Value, Measurements, Recurring | Fair value accounting | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	987		981
Fair Value, Measurements, Recurring | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	25,964		26,410
Fair Value, Measurements, Recurring | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,874,932		2,835,093
Fair Value, Measurements, Recurring | Residential mortgage-backed securities | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,564,286		1,248,510
Fair Value, Measurements, Recurring | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	3,373,760		830,466
Fair Value, Measurements, Recurring | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,413,378		2,879,525
Fair Value, Measurements, Recurring | Municipal bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	100,498		97,580
Fair Value, Measurements, Recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,535		383
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,535		383
Other assets - marketable securities	1,410		28
Total assets	5,945	[4]	411	[5]
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,535		383
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	10,531,511		7,917,584
Other assets - marketable securities			9,240
Total assets	10,566,174	[4]	7,998,509	[5]
Total liabilities	16,868		10,267
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives designated as hedging instruments | Interest rate risks | Interest rate swaps | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	11,441		52,017
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	52
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Currency exchange risks | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	18,326		11,349
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Currency exchange risks | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	16,816		10,267
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Other derivative instruments | Equity Warrant Asset | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	3,923		4,028
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Other derivative instruments | Loan conversion options | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	923		4,291
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Other derivative instruments | Client interest rate derivatives | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	50
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	178,693
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	25,964		26,410
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,874,932		2,835,093
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,564,286		1,248,510
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	3,373,760		830,466
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,413,378		2,879,525
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Municipal bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	100,498		97,580
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	799,962	[4]	547,608	[5]
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Derivatives not designated as hedging instruments | Other derivative instruments | Equity Warrant Asset | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	63,030		43,537
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	736,932		504,071
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Fair value accounting | Venture capital and private equity fund investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	611,824		391,247
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Fair value accounting | Other venture capital investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	124,121		111,843
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Fair value accounting | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	$ 987		$ 981

[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 December 31, 2011 and 2010: December 31, 2011 December 31, 2010 (Dollars in thousands) Amount Ownership % Amount Ownership % SVB Strategic Investors Fund, LP $ 39,567 12.6 % $ 44,722 12.6 % SVB Strategic Investors Fund II, LP 122,619 8.6 94,694 8.6 SVB Strategic Investors Fund III, LP 218,429 5.9 146,613 5.9 SVB Strategic Investors Fund IV, LP 122,076 5.0 40,639 5.0 Strategic Investors Fund V, LP 8,838 0.3 - - SVB Capital Preferred Return Fund, LP 42,580 20.0 23,071 20.0 SVB Capital-NT Growth Partners, LP 43,958 33.0 28,624 33.0 SVB Capital Partners II, LP (i) 2,390 5.1 4,506 5.1 Other private equity fund (ii) 11,367 58.2 8,378 60.6 Total venture capital and private equity fund investments $ 611,824 $ 391,247 (i) At December 31, 2011, 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. (ii) At December 31, 2011, we had a direct ownership interest of 41.5 percent and an indirect ownership interest of 12.6 percent and 4.1 percent in the fund through our ownership interests 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 December 31, 2011 and 2010: December 31, 2011 December 31, 2010 (Dollars in thousands) Amount Ownership % Amount Ownership % Silicon Valley BancVentures, LP $ 17,878 10.7 % $ 21,371 10.7 % SVB Capital Partners II, LP (i) 61,099 5.1 51,545 5.1 SVB India Capital Partners I, LP 42,832 14.4 38,927 14.4 SVB Capital Shanghai Yangpu Venture Capital Fund 2,312 6.8 - - Total other venture capital investments $ 124,121 $ 111,843 (i) At December 31, 2011, 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 December 31, 2011 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.

[4] Included in Level 1 and Level 3 assets are $1.2 million and $647.5 million, respectively, attributable to noncontrolling interests calculated based on the ownership percentages of the noncontrolling interests.

[5] Included in Level 2 and Level 3 assets are $8.1 million and $423.5 million, respectively, attributable to noncontrolling interests calculated based on the ownership percentages of the noncontrolling interests.