Segment Reporting Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net interest income	$ 296,605	$ 289,161	$ 283,336	$ 281,421	$ 269,069	$ 254,660	$ 243,771	$ 238,925	$ 1,150,523	$ 1,006,425	$ 856,595
Provision for loan losses	(7,073)	(18,950)	(36,333)	(33,341)	(31,261)	(33,403)	(26,513)	(6,452)	(95,697)	(97,629)	(59,486)
Noninterest income	113,502	144,140	112,776	86,134	114,506	108,477	126,287	123,524	456,552	472,794	572,239
Noninterest expense	$ (244,567)	$ (221,827)	$ (200,352)	$ (204,033)	$ (208,608)	$ (184,755)	$ (194,112)	$ (190,541)	(870,779)	(778,016)	(707,180)
Income before income tax expense									640,599	603,574	662,168
Total average loans, net of unearned income									18,283,591	14,762,941	11,502,941
Total average assets									43,987,451	40,846,377	32,961,936
Total average deposits									38,759,059	36,293,362	28,320,825
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income									1,040,712	853,882	742,245
Provision for loan losses									(93,885)	(94,913)	(58,635)
Noninterest income									320,421	272,862	203,474
Noninterest expense									(630,760)	(577,477)	(512,245)
Income before income tax expense									636,488	454,354	374,839
Total average loans, net of unearned income									16,047,545	12,984,646	10,144,291
Total average assets									41,494,959	38,439,161	30,183,254
Total average deposits									37,301,483	34,996,194	27,360,721
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income									53,582	44,412	31,427
Provision for loan losses									(1,812)	(2,716)	(851)
Noninterest income									2,713	2,011	1,494
Noninterest expense									(12,379)	(12,185)	(11,314)
Income before income tax expense									42,104	31,522	20,756
Total average loans, net of unearned income									2,025,381	1,592,065	1,155,992
Total average assets									2,035,311	1,588,778	1,176,326
Total average deposits									1,133,425	1,108,411	890,062
SVB Capital
Segment Reporting Information [Line Items]
Net interest income									(49)	3	58
Provision for loan losses									0	0	0
Noninterest income									49,365	70,857	58,058
Noninterest expense									(15,546)	(14,699)	(12,668)
Income before income tax expense									33,770	56,161	45,448
Total average loans, net of unearned income									0	0	0
Total average assets									338,848	337,884	320,129
Total average deposits									0	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income									56,278	108,128	82,865
Provision for loan losses									0	0	0
Noninterest income									84,053	127,064	309,213
Noninterest expense									(212,094)	(173,655)	(170,953)
Income before income tax expense									(71,763)	61,537	221,125
Total average loans, net of unearned income									210,665	186,230	202,658
Total average assets									118,333	480,554	1,282,227
Total average deposits									$ 324,151	$ 188,757	$ 70,042