Segment Reporting - Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Net interest income		$ 309,993	$ 281,421
Provision for credit losses		(29,679)	(33,341)
Provision for credit losses	[1]	30,734	33,475
Noninterest income		117,659	86,134
Noninterest expense	[1]	(237,633)	(203,899)
Income before income tax expense		159,285	130,181
Total average loans, net of unearned income		20,069,314	17,012,435
Total average assets		45,301,034	44,190,190
Total average deposits		39,958,535	39,268,129
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income		275,684	256,178
Provision for credit losses		(28,889)	(32,703)
Noninterest income		79,519	74,759
Noninterest expense		(172,374)	(154,787)
Income before income tax expense		153,940	143,447
Total average loans, net of unearned income		17,647,055	14,919,735
Total average assets		42,888,336	41,533,434
Total average deposits		38,296,563	37,837,645
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income		13,610	13,672
Provision for credit losses		(790)	(638)
Noninterest income		718	627
Noninterest expense		(3,919)	(3,405)
Income before income tax expense		9,619	10,256
Total average loans, net of unearned income		2,245,317	1,871,820
Total average assets		2,259,018	1,893,413
Total average deposits		1,336,849	1,130,736
SVB Capital
Segment Reporting Information [Line Items]
Net interest income		0	0
Provision for credit losses		0	0
Noninterest income		16,775	2,453
Noninterest expense		(3,472)	(3,913)
Income before income tax expense		13,303	(1,460)
Total average loans, net of unearned income		0	0
Total average assets		372,876	349,011
Total average deposits		0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income		20,699	11,571
Provision for credit losses		(1,055)	(134)
Noninterest income		20,647	8,295
Noninterest expense		(57,868)	(41,794)
Income before income tax expense		(17,577)	(22,062)
Total average loans, net of unearned income		176,942	220,880
Total average assets		(219,196)	414,332
Total average deposits		$ 325,123	$ 299,748

[1] Our consolidated statements of income were modified from prior period's presentation to conform to the current period's presentation, which reflects our provision for loan losses and provision for unfunded credit commitments together as our “provision for credit losses”. In prior periods, our provision for unfunded credit commitments were reported as a component of noninterest expense.