Segment Reporting - Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 283,336	$ 243,771	$ 564,757	$ 482,696
(Provision for) reduction of loan losses	(36,333)	(26,513)	(69,674)	(32,965)
Noninterest income	112,776	126,287	198,910	249,811
Noninterest expense	(200,352)	(194,112)	(404,385)	(384,653)
Income before income tax expense	159,427	149,433	289,608	314,889
Total average loans, net of unearned income	18,199,259	14,320,875	17,605,847	14,185,333
Total average assets	43,370,030	39,442,823	43,780,110	38,835,456
Total average deposits	38,159,959	34,956,067	38,714,044	34,412,173
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income (expense)	254,680	203,931	510,858	407,680
(Provision for) reduction of loan losses	(36,454)	(25,592)	(69,169)	(32,052)
Noninterest income	77,310	66,031	152,069	129,224
Noninterest expense	(147,423)	(145,339)	(301,629)	(283,787)
Income before income tax expense	148,113	99,031	292,129	221,065
Total average loans, net of unearned income	16,026,605	12,607,066	15,473,170	12,556,506
Total average assets	40,703,091	37,033,535	41,118,263	36,311,405
Total average deposits	36,690,002	33,713,123	37,263,823	33,094,710
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income (expense)	13,538	11,109	27,210	20,832
(Provision for) reduction of loan losses	121	(921)	(505)	(913)
Noninterest income	762	595	1,389	992
Noninterest expense	(2,954)	(3,231)	(6,359)	(6,107)
Income before income tax expense	11,467	7,552	21,735	14,804
Total average loans, net of unearned income	1,986,659	1,541,016	1,929,239	1,457,547
Total average assets	2,007,009	1,536,508	1,933,123	1,457,570
Total average deposits	1,115,599	1,084,632	1,123,167	1,167,823
SVB Capital
Segment Reporting Information [Line Items]
Net interest income (expense)	(52)	1	(52)	2
(Provision for) reduction of loan losses	0	0	0	0
Noninterest income	11,420	19,909	13,873	40,587
Noninterest expense	(3,684)	(3,704)	(7,597)	(7,190)
Income before income tax expense	7,684	16,206	6,224	33,399
Total average loans, net of unearned income	0	0	0	0
Total average assets	331,500	330,016	340,256	335,690
Total average deposits	0	0	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income (expense)	15,170	28,730	26,741	54,182
(Provision for) reduction of loan losses	0	0	0	0
Noninterest income	23,284	39,752	31,579	79,008
Noninterest expense	(46,291)	(41,838)	(88,800)	(87,569)
Income before income tax expense	(7,837)	26,644	(30,480)	45,621
Total average loans, net of unearned income	185,995	172,793	203,438	171,280
Total average assets	328,430	542,764	388,468	730,791
Total average deposits	$ 354,358	$ 158,312	$ 327,054	$ 149,640