Interim Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total SVBFG Stockholders’ Equity	Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment for adoption of ASU, net of tax | Accounting Standards Update 2014-09		$ (5,802)			$ (5,802)		$ (5,802)
Cumulative adjustment for adoption of ASU, net of tax | Accounting Standards Update 2016-01		74,595			103,766	$ (29,171)	74,595
Balance (in shares) at Dec. 31, 2017			52,835,188
Beginning balance at Dec. 31, 2017		4,319,415	$ 53	$ 1,314,377	2,866,837	(1,472)	4,179,795	$ 139,620
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of stranded tax effect for ASU 2018-02		319
Reclassification of stranded tax effect for ASU 2018-02 | Accounting Standards Update 2018-02					319	(319)
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)			365,767
Common stock issued under employee benefit plans, net of restricted stock cancellations		7,165	$ 0	7,165			7,165
Common stock issued under ESOP (in shares)			9,672
Common stock issued under ESOP		2,577		2,577			2,577
Net income		455,052			432,759		432,759	22,293
Capital calls and distributions, net		(14,725)						(14,725)
Net change in unrealized gains and losses on AFS securities, net of tax		(52,855)				(52,855)	(52,855)
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(1,547)				(1,547)	(1,547)
Foreign currency translation adjustments, net of tax		(1,501)				(1,501)	(1,501)
Share-based compensation, net		22,467		22,467			22,467
Balance (in shares) at Jun. 30, 2018			53,210,627
Ending balance at Jun. 30, 2018		4,804,841	$ 53	1,346,586	3,397,879	(86,865)	4,657,653	147,188
Balance (in shares) at Mar. 31, 2018			52,922,219
Beginning balance at Mar. 31, 2018		4,559,724	$ 53	1,326,998	3,160,081	(71,686)	4,415,446	144,278
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of stranded tax effect for ASU 2018-02		0
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)			288,408
Common stock issued under employee benefit plans, net of restricted stock cancellations		7,644		7,644			7,644
Net income		247,026			237,798		237,798	9,228
Capital calls and distributions, net		(6,318)						(6,318)
Net change in unrealized gains and losses on AFS securities, net of tax		(10,754)				(10,754)	(10,754)
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(674)				(674)	(674)
Foreign currency translation adjustments, net of tax		(3,751)				(3,751)	(3,751)
Share-based compensation, net		11,944		11,944			11,944
Balance (in shares) at Jun. 30, 2018			53,210,627
Ending balance at Jun. 30, 2018		4,804,841	$ 53	1,346,586	3,397,879	(86,865)	4,657,653	147,188
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment for adoption of ASU, net of tax | Accounting Standards Update 2017-08	[1]	(583)			(583)		(583)
Balance (in shares) at Dec. 31, 2018			52,586,498
Beginning balance at Dec. 31, 2018		5,264,843	$ 53	1,378,438	3,791,838	(54,120)	5,116,209	148,634
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of stranded tax effect for ASU 2018-02		0
Acquisition of SVB Leerink		5,256						5,256
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)			467,427
Common stock issued under employee benefit plans, net of restricted stock cancellations		7,853	$ 0	7,853			7,853
Common stock issued under ESOP (in shares)			14,442
Common stock issued under ESOP		3,506		3,506			3,506
Net income		628,183			606,719		606,719	21,464
Capital calls and distributions, net		(23,222)						(23,222)
Net change in unrealized gains and losses on AFS securities, net of tax		122,597				122,597	122,597
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(1,005)				(1,005)	(1,005)
Foreign currency translation adjustments, net of tax		(68)				(68)	(68)
Net change in unrealized gains and losses on cash flow hedges, net of tax		13,828				13,828	13,828
Share-based compensation, net		31,768		31,768			31,768
Common stock repurchases (in shares)			(1,506,648)
Common stock repurchases		(346,781)	$ (1)		(346,780)		(346,781)
Balance (in shares) at Jun. 30, 2019			51,561,719
Ending balance at Jun. 30, 2019		5,706,175	$ 52	1,421,565	4,051,194	81,232	5,554,043	152,132
Balance (in shares) at Mar. 31, 2019			52,322,105
Beginning balance at Mar. 31, 2019		5,483,823	$ 52	1,394,130	3,963,965	(15,374)	5,342,773	141,050
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of stranded tax effect for ASU 2018-02		0
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)			257,684
Common stock issued under employee benefit plans, net of restricted stock cancellations		10,789		10,789			10,789
Net income		336,571			317,987		317,987	18,584
Capital calls and distributions, net		(7,502)						(7,502)
Net change in unrealized gains and losses on AFS securities, net of tax		86,186				86,186	86,186
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(519)				(519)	(519)
Foreign currency translation adjustments, net of tax		(2,092)				(2,092)	(2,092)
Net change in unrealized gains and losses on cash flow hedges, net of tax		13,031				13,031	13,031
Share-based compensation, net		16,646		16,646			16,646
Common stock repurchases (in shares)			(1,018,070)
Common stock repurchases		(230,758)	$ 0		(230,758)		(230,758)
Balance (in shares) at Jun. 30, 2019			51,561,719
Ending balance at Jun. 30, 2019		$ 5,706,175	$ 52	$ 1,421,565	$ 4,051,194	$ 81,232	$ 5,554,043	$ 152,132

[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.