Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting Information [Line Items]
Net interest income	$ 160,563	$ 154,430	$ 151,934	$ 150,937	$ 140,070	$ 135,455	$ 130,453	$ 120,299	$ 617,864		$ 526,277		$ 418,135
(Provision for) reduction of loan losses									(44,330)		(6,101)		(44,628)
Noninterest income	126,688	69,139	80,426	59,293	73,059	95,611	123,708	89,954	335,546		382,332		247,530
Noninterest expense	(143,049)	(135,171)	(135,766)	(132,012)	(134,710)	(127,451)	(121,032)	(117,435)	(545,998)	[1]	(500,628)	[1]	(422,818)	[1]
Income before income tax expense									363,082	[2]	401,880	[2]	198,219	[2]
Total average loans, net of unearned income									7,558,928		5,815,071		4,435,911
Total average assets									21,311,172	[3]	18,670,499	[3]	14,858,236	[3]
Total average deposits									17,910,088		15,568,801		12,028,327
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income									595,133	[4]	519,145	[4]	424,256	[4]
(Provision for) reduction of loan losses									(45,417)	[4]	(13,494)	[4]	(42,357)	[4]
Noninterest income									188,842	[4]	150,116	[4]	136,531	[4]
Noninterest expense									(397,672)	[1],[4]	(355,705)	[1],[4]	(305,454)	[1],[4]
Income before income tax expense									340,886	[2],[4]	300,062	[2],[4]	212,976	[2],[4]
Total average loans, net of unearned income									6,790,332	[4]	5,099,516	[4]	3,948,872	[4]
Total average assets									19,523,139	[3],[4]	17,104,227	[3],[4]	13,558,116	[3],[4]
Total average deposits									17,575,060	[4]	15,364,804	[4]	11,911,639	[4]
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income									21,807		19,529		15,756
(Provision for) reduction of loan losses									1,087		7,393		(2,271)
Noninterest income									681		516		496
Noninterest expense									(14,118)	[1]	(10,174)	[1]	(4,405)	[1]
Income before income tax expense									9,457	[2]	17,264	[2]	9,576	[2]
Total average loans, net of unearned income									758,471		658,175		461,620
Total average assets									763,186	[3]	658,797	[3]	461,697	[3]
Total average deposits									313,836		186,604		129,536
SVB Capital
Segment Reporting Information [Line Items]
Net interest income									15	[4]	10	[4]	0	[4]
(Provision for) reduction of loan losses									0	[4]	0	[4]	0	[4]
Noninterest income									27,435	[4]	27,358	[4]	19,491	[4]
Noninterest expense									(11,263)	[1],[4]	(13,079)	[1],[4]	(15,652)	[1],[4]
Income before income tax expense									16,187	[2],[4]	14,289	[2],[4]	3,839	[2],[4]
Total average loans, net of unearned income									0	[4]	0	[4]	0	[4]
Total average assets									239,335	[3],[4]	226,423	[3],[4]	157,461	[3],[4]
Total average deposits									0	[4]	0	[4]	0	[4]
Other Items
Segment Reporting Information [Line Items]
Net interest income									909		(12,407)		(21,877)
(Provision for) reduction of loan losses									0		0		0
Noninterest income									118,588		204,342		91,012
Noninterest expense									(122,945)	[1]	(121,670)	[1]	(97,307)	[1]
Income before income tax expense									(3,448)	[2]	70,265	[2]	(28,172)	[2]
Total average loans, net of unearned income									10,125		57,380		25,419
Total average assets									785,512	[3]	681,052	[3]	680,962	[3]
Total average deposits									$ 21,192		$ 17,393		$ (12,848)

[1] The Global Commercial Bank segment includes direct depreciation and amortization of $16.3 million, $12.2 million and $9.7 million for 2012, 2011 and 2010, 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 interest for all periods presented.