Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Segment Reporting Information [Line Items]
Net interest income (loss)	$ 154,430		$ 135,455		$ 457,301		$ 386,207
(Provision for) reduction of loan losses	(6,788)		(769)		(29,316)		2,144
Noninterest income	69,139		95,611		208,858		309,273
Noninterest expense	(135,171)	[1]	(127,451)	[1]	(402,949)	[1]	(365,918)	[1]
Income (loss) before income tax expense	81,610	[2]	102,846	[2]	233,894	[2]	331,706	[2]
Total average loans, net of unearned income	7,907,606		6,006,614		7,318,537		5,619,709
Total average assets	21,727,197	[3]	18,796,510	[3]	20,953,041	[3]	18,336,848	[3]
Total average deposits	18,260,344		15,804,036		17,547,194		15,250,938
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income (loss)	151,858	[4]	133,946	[4]	441,542	[4]	380,461	[4]
(Provision for) reduction of loan losses	(7,787)	[4]	(3,883)	[4]	(29,946)	[4]	(3,222)	[4]
Noninterest income	46,965	[4]	39,189	[4]	139,387	[4]	110,604	[4]
Noninterest expense	(97,846)	[1],[4]	(92,350)	[1],[4]	(292,580)	[1],[4]	(262,932)	[1],[4]
Income (loss) before income tax expense	93,190	[2],[4]	76,902	[2],[4]	258,403	[2],[4]	224,911	[2],[4]
Total average loans, net of unearned income	7,159,609	[4]	5,263,448	[4]	6,559,036	[4]	4,933,707	[4]
Total average assets	19,861,275	[3],[4]	17,347,197	[3],[4]	19,149,952	[3],[4]	16,788,462	[3],[4]
Total average deposits	17,881,175	[4]	15,573,886	[4]	17,240,715	[4]	15,063,215	[4]
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income (loss)	5,666		5,513		16,147		14,567
(Provision for) reduction of loan losses	999		3,114		630		5,366
Noninterest income	149		128		457		351
Noninterest expense	(3,749)	[1]	(2,846)	[1]	(10,338)	[1]	(7,326)	[1]
Income (loss) before income tax expense	3,065	[2]	5,909	[2]	6,896	[2]	12,958	[2]
Total average loans, net of unearned income	755,001		684,613		745,069		637,443
Total average assets	758,988	[3]	685,308	[3]	749,500	[3]	637,854	[3]
Total average deposits	341,537		200,547		278,736		169,368
SVB Capital
Segment Reporting Information [Line Items]
Net interest income (loss)	6	[4]	2	[4]	22	[4]	6	[4]
(Provision for) reduction of loan losses	0	[4]	0	[4]	0	[4]	0	[4]
Noninterest income	4,330	[4]	9,873	[4]	12,474	[4]	23,879	[4]
Noninterest expense	(3,562)	[1],[4]	(3,860)	[1],[4]	(8,970)	[1],[4]	(10,113)	[1],[4]
Income (loss) before income tax expense	774	[2],[4]	6,015	[2],[4]	3,526	[2],[4]	13,772	[2],[4]
Total average loans, net of unearned income	0	[4]	0	[4]	0	[4]	0	[4]
Total average assets	238,595	[3],[4]	238,949	[3],[4]	243,124	[3],[4]	225,041	[3],[4]
Total average deposits	0	[4]	0	[4]	0	[4]	0	[4]
Other Items
Segment Reporting Information [Line Items]
Net interest income (loss)	(3,100)		(4,006)		(410)		(8,827)
(Provision for) reduction of loan losses	0		0		0		0
Noninterest income	17,695		46,421		56,540		174,439
Noninterest expense	(30,014)	[1]	(28,395)	[1]	(91,061)	[1]	(85,547)	[1]
Income (loss) before income tax expense	(15,419)	[2]	14,020	[2]	(34,931)	[2]	80,065	[2]
Total average loans, net of unearned income	(7,004)		58,553		14,432		48,559
Total average assets	868,339	[3]	525,056	[3]	810,465	[3]	685,491	[3]
Total average deposits	$ 37,632		$ 29,603		$ 27,743		$ 18,355

[1] The Global Commercial Bank segment includes direct depreciation and amortization of $4.5 million and $3.1 million for the three months ended September 30, 2012 and 2011, respectively, and $11.6 million and $8.7 million for the nine months ended September 30, 2012 and 2011, respectively.

[2] The internal reporting model used by management to assess segment performance does not calculate income tax expense by segment. Our effective tax rate is a reasonable approximation of the segment rates.

[3] Total average assets equals the greater of total average assets or the sum of total liabilities and total stockholders’ equity for each segment.

[4] Global Commercial Bank’s and SVB Capital’s components of net interest income, noninterest income, noninterest expense and total average assets are shown net of noncontrolling interests for all periods presented.