Segment Reporting - Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net interest income	$ 281,421	$ 238,925
Provision for loan losses	(33,341)	(6,452)
Noninterest income	86,134	123,524
Noninterest expense	(204,033)	(190,541)
Income before income tax expense	130,181	165,456
Total average loans, net of unearned income	17,012,435	14,048,285
Total average assets	44,190,190	38,221,341
Total average deposits	39,268,129	33,862,236
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income	256,178	203,749
Provision for loan losses	(32,703)	(6,460)
Noninterest income	74,759	63,193
Noninterest expense	(154,206)	(138,448)
Income before income tax expense	144,028	122,034
Total average loans, net of unearned income	14,919,735	12,505,385
Total average assets	41,533,434	35,581,252
Total average deposits	37,837,645	32,469,427
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income	13,672	9,723
Provision for loan losses	(638)	8
Noninterest income	627	397
Noninterest expense	(3,405)	(2,876)
Income before income tax expense	10,256	7,252
Total average loans, net of unearned income	1,871,820	1,373,149
Total average assets	1,893,413	1,445,871
Total average deposits	1,130,736	1,251,939
SVB Capital
Segment Reporting Information [Line Items]
Net interest income	0	1
Provision for loan losses	0	0
Noninterest income	2,453	20,678
Noninterest expense	(3,913)	(3,486)
Income before income tax expense	(1,460)	17,193
Total average loans, net of unearned income	0	0
Total average assets	349,011	269,982
Total average deposits	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income	11,571	25,452
Provision for loan losses	0	0
Noninterest income	8,295	39,256
Noninterest expense	(42,509)	(45,731)
Income before income tax expense	(22,643)	18,977
Total average loans, net of unearned income	220,880	169,751
Total average assets	414,332	924,236
Total average deposits	$ 299,748	$ 140,870