Segment Reporting - Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Segment Reporting Information [Line Items]
Net interest income		$ 254,660	$ 220,565	$ 737,356	[1]	$ 621,858
Provision for loan losses		(33,403)	(16,610)	(66,368)	[1]	(19,051)
Noninterest income		108,477	80,167	358,288	[1]	404,602
Noninterest expense	[2]	(184,755)	(179,761)	(569,408)	[1]	(521,113)
Income before income tax expense	[2]	144,979	104,361	459,868	[1]	486,296
Total average loans, net of unearned income		14,916,652	11,439,521	14,431,785		11,098,397
Total average assets		42,019,224	34,596,065	39,911,525		31,402,952
Total average deposits		37,383,067	29,726,284	35,413,353		26,882,113
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income		217,929	187,184	625,618		540,533
Provision for loan losses		(32,076)	(16,185)	(64,128)		(18,833)
Noninterest income		68,517	57,714	197,740		169,376
Noninterest expense		(135,504)	(127,050)	(415,245)		(369,587)
Income before income tax expense		118,866	101,663	343,985		321,489
Total average loans, net of unearned income		13,031,928	10,022,333	12,721,208		9,766,870
Total average assets		40,211,915	31,916,581	37,954,846		28,924,331
Total average deposits		36,149,772	28,795,499	34,125,675		26,020,715
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income		11,667	7,344	32,499		23,529
Provision for loan losses		(1,327)	(425)	(2,240)		(218)
Noninterest income		506	491	1,498		1,121
Noninterest expense		(2,703)	(2,574)	(8,589)		(7,709)
Income before income tax expense		8,143	4,836	23,168		16,723
Total average loans, net of unearned income		1,669,858	1,189,976	1,529,095		1,119,618
Total average assets		1,273,823	1,128,938	1,659,981		1,026,678
Total average deposits		1,041,773	877,701	1,125,345		805,167
SVB Capital
Segment Reporting Information [Line Items]
Net interest income		1	12	3		55
Provision for loan losses		0	0	0		0
Noninterest income		17,332	1,064	57,919		35,617
Noninterest expense		(3,745)	(3,036)	(10,935)		(8,815)
Income before income tax expense		13,588	(1,960)	46,987		26,857
Total average loans, net of unearned income		0	0	0		0
Total average assets		334,045	302,949	335,136		328,048
Total average deposits		0	0	0		0
Other Items
Segment Reporting Information [Line Items]
Net interest income		25,063	26,025	79,236		57,741
Provision for loan losses		0	0	0		0
Noninterest income		22,122	20,898	101,131		198,488
Noninterest expense		(42,803)	(47,101)	(134,639)		(135,002)
Income before income tax expense		4,382	(178)	45,728		121,227
Total average loans, net of unearned income		214,866	227,212	181,482		211,909
Total average assets		199,441	1,247,597	(38,438)		1,123,895
Total average deposits		$ 191,522	$ 53,084	$ 162,333		$ 56,231

[1] Amounts for the nine months ended September 30, 2015, have been revised to reflect the retrospective application of new accounting guidance adopted in the second quarter of 2015 related to our consolidated variable interest entities (ASU 2015-02). Amounts prior to January 1, 2015 have not been revised for the adoption of this guidance. See Note 1— "Basis of Presentation” of the “Notes to Interim Consolidated Financial Statements (unaudited)” under Part I, Item 1 of this report for additional details.

[2] Prior period amounts have been revised to reflect the retrospective application of new accounting guidance adopted in the first quarter of 2015 related to our investments in qualified affordable housing projects (ASU 2014-01). See Note 1— "Basis of Presentation" of the "Notes to Interim Consolidated Financial Statements" under Part I, Item 1 in this report.