Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 11,527,541		$ 10,536,046
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	9,884		11,441
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	71,404		66,953
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	620,356	[1]	611,824	[1]
Fair value accounting | Other venture capital investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	127,951	[2]	124,121	[2]
Fair value accounting | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	1,002	[3]	987	[3]
U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	25,775		25,964
U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	3,025,354		2,874,932
Residential mortgage-backed securities | Agency-issued mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,815,093		1,564,286
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	4,058,585		3,373,760
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	2,271,203		2,413,378
Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	228,630		178,693
Municipal bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	100,103		100,498
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,798		4,535
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	11,527,541		10,536,046
Marketable securities	1,898		1,410
Total assets	12,373,102	[4]	11,372,081	[5]
Total liabilities	11,319		16,868
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	9,884		11,441
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	65		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	11,594		18,326
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	11,254		16,816
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	71,404		66,953
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	1,409		923
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	63		50
Fair Value, Measurements, Recurring | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	749,309		736,932
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	620,356		611,824
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	127,951		124,121
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	1,002		987
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	25,775		25,964
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	3,025,354		2,874,932
Fair Value, Measurements, Recurring | Residential mortgage-backed securities | Agency-issued mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,815,093		1,564,286
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	4,058,585		3,373,760
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	2,271,203		2,413,378
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	228,630		178,693
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	100,103		100,498
Fair Value, Measurements, Recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,798		4,535
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	2,798		4,535
Marketable securities	1,898		1,410
Total assets	4,696	[4]	5,945	[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	2,798		4,535
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	814,526	[4]	799,962	[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	65,217		63,030
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	749,309		736,932
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	620,356		611,824
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	127,951		124,121
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	1,002		987
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	11,524,743		10,531,511
Total assets	11,553,880	[4]	10,566,174	[5]
Total liabilities	11,319		16,868
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	9,884		11,441
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	65		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	11,594		18,326
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	11,254		16,816
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	6,187		3,923
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	1,409		923
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	63		50
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	25,775		25,964
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	3,025,354		2,874,932
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities | Agency-issued mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,815,093		1,564,286
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	4,058,585		3,373,760
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	2,271,203		2,413,378
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	228,630		178,693
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	$ 100,103		$ 100,498

[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 March 31, 2012 and December 31, 2011: March 31, 2012 December 31, 2011 (Dollars in thousands) Amount Ownership % Amount Ownership % SVB Strategic Investors Fund, LP $ 36,444 12.6 % $ 39,567 12.6 % SVB Strategic Investors Fund II, LP 119,965 8.6 122,619 8.6 SVB Strategic Investors Fund III, LP 216,827 5.9 218,429 5.9 SVB Strategic Investors Fund IV, LP 130,139 5.0 122,076 5.0 Strategic Investors Fund V, LP 11,461 0.2 8,838 0.3 SVB Capital Preferred Return Fund, LP 46,783 20.0 42,580 20.0 SVB Capital-NT Growth Partners, LP 50,449 33.0 43,958 33.0 SVB Capital Partners II, LP (i) 1,221 5.1 2,390 5.1 Other private equity fund (ii) 7,067 58.2 11,367 58.2 Total venture capital and private equity fund investments $ 620,356 $ 611,824 (i) At March 31, 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 March 31, 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 March 31, 2012 and December 31, 2011: March 31, 2012 December 31, 2011 (Dollars in thousands) Amount Ownership % Amount Ownership % Silicon Valley BancVentures, LP $ 17,344 10.7 % $ 17,878 10.7 % SVB Capital Partners II, LP (i) 64,829 5.1 61,099 5.1 SVB India Capital Partners I, LP 42,299 14.4 42,832 14.4 SVB Capital Shanghai Yangpu Venture Capital Fund 3,479 6.8 2,312 6.8 Total other venture capital investments $ 127,951 $ 124,121 (i) At March 31, 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 March 31, 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] Included in Level 1 and Level 3 assets are $1.6 million and $661.9 million, respectively, attributable to noncontrolling interests calculated based on the ownership percentages of the noncontrolling interests.

[5] 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.