Segment Reporting - Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Net interest income	$ 289,161	$ 254,660	$ 853,918	$ 737,356
Provision for loan losses	(18,950)	(33,403)	(88,624)	(66,368)
Noninterest income	144,140	108,477	343,050	358,288
Noninterest expense	(221,827)	(184,755)	(626,212)	(569,408)
Income before income tax expense	192,524	144,979	482,132	459,868
Total average loans, net of unearned income	18,647,194	14,916,652	17,955,497	14,431,785
Total average assets	43,451,329	42,014,220	43,669,716	39,906,689
Total average deposits	37,909,754	37,383,067	38,443,990	35,413,353
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income	262,484	217,932	773,342	625,611
Provision for loan losses	(16,974)	(32,074)	(86,143)	(64,126)
Noninterest income	79,226	68,517	231,295	197,740
Noninterest expense	(159,429)	(137,637)	(461,058)	(421,425)
Income before income tax expense	165,307	116,738	457,436	337,800
Total average loans, net of unearned income	16,357,099	13,047,507	15,769,964	12,721,972
Total average assets	40,829,515	39,688,677	41,021,311	37,449,533
Total average deposits	36,484,125	36,151,235	37,002,027	34,124,748
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income	13,298	11,667	40,508	32,499
Provision for loan losses	(1,976)	(1,329)	(2,481)	(2,242)
Noninterest income	664	506	2,053	1,498
Noninterest expense	(3,122)	(2,761)	(9,481)	(8,869)
Income before income tax expense	8,864	8,083	30,599	22,886
Total average loans, net of unearned income	2,074,982	1,669,858	1,978,175	1,529,095
Total average assets	2,091,244	1,664,602	1,986,215	1,527,339
Total average deposits	1,115,446	1,041,773	1,120,575	1,125,345
SVB Capital
Segment Reporting Information [Line Items]
Net interest income	1	1	(51)	3
Provision for loan losses	0	0	0	0
Noninterest income	30,619	17,332	44,492	57,919
Noninterest expense	(3,924)	(3,745)	(11,521)	(10,935)
Income before income tax expense	26,696	13,588	32,920	46,987
Total average loans, net of unearned income	0	0	0	0
Total average assets	325,321	334,045	334,328	335,136
Total average deposits	0	0	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income	13,378	25,060	40,119	79,243
Provision for loan losses	0	0	0	0
Noninterest income	33,631	22,122	65,210	101,131
Noninterest expense	(55,352)	(40,612)	(144,152)	(128,179)
Income before income tax expense	(8,343)	6,570	(38,823)	52,195
Total average loans, net of unearned income	215,113	199,287	207,358	180,718
Total average assets	205,249	326,896	327,862	594,681
Total average deposits	$ 310,183	$ 190,059	$ 321,388	$ 163,260