Segment Reporting - Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Segment Reporting Information [Line Items]
Net interest income	$ 238,890		$ 196,328
(Provision for) reduction of loan losses	(6,452)		(494)
Noninterest income	172,018		310,225
Noninterest expense	(196,108)	[1]	(170,408)	[1],[2]
Income before income tax expense	208,348	[3]	335,651	[2],[3]
Total average loans, net of unearned income	14,046,369		10,767,684
Total average assets	39,300,589	[4]	27,767,633	[4]
Total average deposits	33,857,779		23,676,448
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income	203,755	[5]	175,303	[5]
(Provision for) reduction of loan losses	(6,460)	[5]	(807)	[5]
Noninterest income	64,689	[5]	58,635	[5]
Noninterest expense	(136,282)	[1],[5]	(120,706)	[1],[5]
Income before income tax expense	125,702	[3],[5]	112,425	[3],[5]
Total average loans, net of unearned income	12,729,630	[5]	9,677,957	[5]
Total average assets	35,962,427	[4],[5]	25,504,407	[4],[5]
Total average deposits	32,472,827	[5]	22,877,819	[5]
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income	9,723		6,892
(Provision for) reduction of loan losses	8		313
Noninterest income	397		274
Noninterest expense	(2,747)	[1]	(2,495)	[1]
Income before income tax expense	7,381	[3]	4,984	[3]
Total average loans, net of unearned income	1,374,189		1,049,901
Total average assets	1,921,554	[4]	967,873	[4]
Total average deposits	1,251,939		745,083
SVB Capital
Segment Reporting Information [Line Items]
Net interest income	(24)	[5]	14	[5]
(Provision for) reduction of loan losses	0	[5]	0	[5]
Noninterest income	21,141	[5]	37,672	[5]
Noninterest expense	(3,891)	[1],[5]	(2,635)	[1],[5]
Income before income tax expense	17,226	[3],[5]	35,051	[3],[5]
Total average loans, net of unearned income	0	[5]	0	[5]
Total average assets	269,982	[4],[5]	340,990	[4],[5]
Total average deposits	0	[5]	0	[5]
Other Items
Segment Reporting Information [Line Items]
Net interest income	25,436	[6]	14,119	[6]
(Provision for) reduction of loan losses	0	[6]	0	[6]
Noninterest income	85,791	[6]	213,644	[6]
Noninterest expense	(53,188)	[1],[6]	(44,572)	[1],[6]
Income before income tax expense	58,039	[3],[6]	183,191	[3],[6]
Total average loans, net of unearned income	(57,450)	[6]	39,826	[6]
Total average assets	1,146,626	[4],[6]	954,363	[4],[6]
Total average deposits	$ 133,013	[6]	$ 53,546	[6]

[1] The Global Commercial Bank segment includes direct depreciation and amortization of $5.1 million and $4.9 million for the three months ended March 31, 2015 and 2014, respectively

[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.

[3] 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.

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

[5] 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. Noncontrolling interest is included within "Other Items".

[6] The "Other Items" column reflects the adjustments necessary to reconcile the results of the operating segments to the consolidated financial statements prepared in conformity with GAAP. Noninterest income is primarily attributable to noncontrolling interests and gains on equity warrant assets. Noninterest expense primarily consists of expenses associated with corporate support functions such as finance, human resources, marketing, legal and other expenses. Additionally, average assets primarily consist of cash and cash equivalents and loans from our Community Development Finance practice as part of our responsibilities under the Community Reinvestment Act.