Interim Consolidated Statements of Stockholders' Equity - USD ($)		Total	Cumulative adjustment for the adoption of amendment	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative adjustment for the adoption of amendment	Accumulated Other Comprehensive Income (Loss)	Total SVBFG Stockholders’ Equity	Total SVBFG Stockholders’ Equity Cumulative adjustment for the adoption of amendment	Noncontrolling Interests
Balance (in shares) at Dec. 31, 2018					52,586,498
Balance, beginning of period, net of tax at Dec. 31, 2018		$ 5,264,843,000		$ 0	$ 53,000	$ 1,378,438,000	$ 3,791,838,000		$ (54,120,000)	$ 5,116,209,000		$ 148,634,000
Balance, beginning of period, net of tax (Accounting Standards Update 2017-08) at Dec. 31, 2018	[1]		$ (583,000)					$ (583,000)			$ (583,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition of SVB Leerink		5,256,000										5,256,000
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)					487,101
Common stock issued under employee benefit plans, net of restricted stock cancellations		9,236,000			$ 0	9,236,000				9,236,000
Common stock issued under ESOP (in shares)					14,442
Common stock issued under ESOP		3,506,000				3,506,000				3,506,000
Net income		909,901,000					874,000,000			874,000,000		35,901,000
Capital calls and distributions, net		(32,002,000)										(32,002,000)
Net change in unrealized gains and losses on AFS securities, net of tax		173,235,000							173,235,000	173,235,000
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(1,275,000)							(1,275,000)	(1,275,000)
Foreign currency translation adjustments, net of tax		(4,550,000)							(4,550,000)	(4,550,000)
Net change in unrealized gains and losses on cash flow hedges, net of tax		22,863,000							22,863,000	22,863,000
Share-based compensation, net		50,550,000				50,550,000				50,550,000
Common stock repurchases (in shares)					(1,532,210)
Common stock repurchases		(352,511,000)			$ (1,000)		(352,510,000)			(352,511,000)
Balance (in shares) at Sep. 30, 2019					51,555,831
Balance, end of period, net of tax at Sep. 30, 2019		6,048,469,000		0	$ 52,000	1,441,730,000	4,312,745,000		136,153,000	5,890,680,000		157,789,000
Balance (in shares) at Jun. 30, 2019					51,561,719
Balance, beginning of period, net of tax at Jun. 30, 2019		5,706,175,000		0	$ 52,000	1,421,565,000	4,051,194,000		81,232,000	5,554,043,000		152,132,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)					19,674
Common stock issued under employee benefit plans, net of restricted stock cancellations		1,383,000				1,383,000				1,383,000
Net income		281,718,000					267,281,000			267,281,000		14,437,000
Capital calls and distributions, net		(8,780,000)										(8,780,000)
Net change in unrealized gains and losses on AFS securities, net of tax		50,638,000							50,638,000	50,638,000
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(270,000)							(270,000)	(270,000)
Foreign currency translation adjustments, net of tax		(4,482,000)							(4,482,000)	(4,482,000)
Net change in unrealized gains and losses on cash flow hedges, net of tax		9,035,000							9,035,000	9,035,000
Share-based compensation, net		18,782,000				18,782,000				18,782,000
Common stock repurchases (in shares)					(25,562)
Common stock repurchases		(5,730,000)					(5,730,000)			(5,730,000)
Balance (in shares) at Sep. 30, 2019					51,555,831
Balance, end of period, net of tax at Sep. 30, 2019		6,048,469,000		0	$ 52,000	1,441,730,000	4,312,745,000		136,153,000	5,890,680,000		157,789,000
Balance (in shares) at Dec. 31, 2019					51,655,607
Balance, beginning of period, net of tax at Dec. 31, 2019		6,621,080,000		340,138,000	$ 52,000	1,470,071,000	4,575,601,000		84,445,000	6,470,307,000		150,773,000
Balance, beginning of period, net of tax (Accounting Standards Update 2016-13) at Dec. 31, 2019	[1]		$ (35,049,000)					$ (35,049,000)			$ (35,049,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)					364,494
Common stock issued under employee benefit plans, net of restricted stock cancellations		15,691,000			$ 0	15,691,000				15,691,000
Common stock issued under ESOP (in shares)					12,094
Common stock issued under ESOP		2,447,000				2,447,000				2,447,000
Net income		855,493,000					815,458,000			815,458,000		40,035,000
Capital calls and distributions, net		(16,363,000)										(16,363,000)
Net change in unrealized gains and losses on AFS securities, net of tax		392,725,000							392,725,000	392,725,000
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(765,000)							(765,000)	(765,000)
Foreign currency translation adjustments, net of tax		871,000							871,000	871,000
Net change in unrealized gains and losses on cash flow hedges, net of tax		143,118,000							143,118,000	143,118,000
Share-based compensation, net		60,733,000				60,733,000				60,733,000
Common stock repurchases (in shares)					(244,223)
Common stock repurchases		(60,020,000)			$ 0		(60,020,000)			(60,020,000)
Dividends on preferred stock		(12,557,000)					(12,557,000)			(12,557,000)
Other		(24,000)				(24,000)				(24,000)
Balance (in shares) at Sep. 30, 2020					51,787,972
Balance, end of period, net of tax at Sep. 30, 2020		7,967,380,000		340,138,000	$ 52,000	1,548,918,000	5,283,433,000		620,394,000	7,792,935,000		174,445,000
Balance (in shares) at Jun. 30, 2020					51,740,714
Balance, beginning of period, net of tax at Jun. 30, 2020		7,468,313,000		340,138,000	$ 52,000	1,522,728,000	4,841,720,000		614,735,000	7,319,373,000		148,940,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)					47,258
Common stock issued under employee benefit plans, net of restricted stock cancellations		4,797,000				4,797,000				4,797,000
Net income		474,055,000					446,307,000			446,307,000		27,748,000
Capital calls and distributions, net		(2,243,000)										(2,243,000)
Net change in unrealized gains and losses on AFS securities, net of tax		10,018,000							10,018,000	10,018,000
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(266,000)							(266,000)	(266,000)
Foreign currency translation adjustments, net of tax		7,475,000							7,475,000	7,475,000
Net change in unrealized gains and losses on cash flow hedges, net of tax		(11,568,000)							(11,568,000)	(11,568,000)
Share-based compensation, net		21,408,000				21,408,000				21,408,000
Dividends on preferred stock		(4,594,000)					(4,594,000)			(4,594,000)
Other		(15,000)				(15,000)				(15,000)
Balance (in shares) at Sep. 30, 2020					51,787,972
Balance, end of period, net of tax at Sep. 30, 2020		$ 7,967,380,000		$ 340,138,000	$ 52,000	$ 1,548,918,000	$ 5,283,433,000		$ 620,394,000	$ 7,792,935,000		$ 174,445,000

[1] See "Adoption of New Accounting Standards" in Note 1 — “Basis of Presentation” of the “Notes to Interim Consolidated Financial Statements (unaudited)” under Part I, Item 1 of this report for additional details.