Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Segment Reporting Information [Line Items]
Net interest income	$ 140,070	$ 135,455	$ 130,453	$ 120,299	$ 104,518	$ 106,341	$ 106,436	$ 100,840	$ 526,277		$ 418,135		$ 382,150
(Provision for) reduction of loan losses									(6,101)		(44,628)		(90,180)
Noninterest income (loss)									382,332		247,530		97,743
Noninterest expense, excluding impairment of goodwill													(339,774)	[1]
Noninterest expense	(134,710)	(127,451)	(121,032)	(117,435)	(115,891)	(104,171)	(104,180)	(98,576)	(500,628)	[1]	(422,818)	[1]	(343,866)
Impairment of goodwill													(4,092)
Income (loss) before income tax expense	70,174	102,846	132,995	95,865	44,987	77,435	35,005	40,792	401,880	[2]	198,219	[2]	45,847	[2]
Total average loans									5,815,071		4,435,911		4,699,696
Total average assets									18,670,499		14,858,236		11,326,341
Total average deposits									15,568,801		12,028,327		8,794,099
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income									445,466	[3]	367,927	[3]	380,668	[3]
(Provision for) reduction of loan losses									(13,494)	[3]	(42,357)	[3]	(79,867)	[3]
Noninterest income (loss)									150,116	[3]	136,531	[3]	119,834	[3]
Noninterest expense, excluding impairment of goodwill													(237,475)	[1],[3]
Noninterest expense									(358,712)	[1],[3]	(307,508)	[1],[3]
Impairment of goodwill													(4,092)	[3]
Income (loss) before income tax expense									223,376	[2],[3]	154,593	[2],[3]	179,068	[2],[3]
Total average loans									5,099,516	[3]	3,948,872	[3]	4,188,908	[3]
Total average assets									5,603,935	[3]	4,281,745	[3]	4,370,702	[3]
Total average deposits									15,364,804	[3]	11,911,639	[3]	8,679,761	[3]
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income									20,466		13,015		14,176
(Provision for) reduction of loan losses									7,393		(2,271)		(10,313)
Noninterest income (loss)									516		496		371
Noninterest expense, excluding impairment of goodwill													(2,989)	[1]
Noninterest expense									(10,174)	[1]	(4,405)	[1]
Income (loss) before income tax expense									18,201	[2]	6,835	[2]	1,245	[2]
Total average loans									658,175		461,620		487,825
Total average assets									658,797		461,697		487,990
Total average deposits									186,604		129,536		107,602
SVB Capital
Segment Reporting Information [Line Items]
Net interest income									10	[3]			(16)	[3]
Noninterest income (loss)									27,358	[3]	19,491	[3]	2,365	[3]
Noninterest expense, excluding impairment of goodwill													(15,140)	[1],[3]
Noninterest expense									(13,079)	[1],[3]	(15,652)	[1],[3]
Income (loss) before income tax expense									14,289	[2],[3]	3,839	[2],[3]	(12,791)	[2],[3]
Total average assets									226,423	[3]	157,461	[3]	136,176	[3]
Other Items
Segment Reporting Information [Line Items]
Net interest income									60,335		37,193		(12,678)
Noninterest income (loss)									204,342		91,012		(24,827)
Noninterest expense, excluding impairment of goodwill													(84,170)	[1]
Noninterest expense									(118,663)	[1]	(95,253)	[1]
Income (loss) before income tax expense									146,014	[2]	32,952	[2]	(121,675)	[2]
Total average loans									57,380		25,419		22,963
Total average assets									12,181,344		9,957,333		6,331,473
Total average deposits									$ 17,393		$ (12,848)		$ 6,736

[1] The Global Commercial Bank segment includes direct depreciation and amortization of $12.2 million, $9.7 million and $9.9 million in 2011, 2010 and 2009, respectively.

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

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