Interim Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive 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)			77,359
Common stock issued under employee benefit plans, net of restricted stock cancellations		(479)	$ 0	(479)			(479)
Common stock issued under ESOP (in shares)			9,672
Common stock issued under ESOP		2,577		2,577			2,577
Net income		208,026			194,961		194,961	13,065
Capital calls and distributions, net		(8,407)						(8,407)
Net change in unrealized gains and losses on AFS securities, net of tax		(42,101)				(42,101)	(42,101)
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(873)				(873)	(873)
Foreign currency translation adjustments, net of tax		2,250				2,250	2,250
Share-based compensation, net		10,523		10,523			10,523
Balance (in shares) at Mar. 31, 2018			52,922,219
Ending 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]
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)			209,743
Common stock issued under employee benefit plans, net of restricted stock cancellations		(2,936)	$ 0	(2,936)			(2,936)
Common stock issued under ESOP (in shares)			14,442
Common stock issued under ESOP		3,506		3,506			3,506
Net income		291,612			288,732		288,732	2,880
Capital calls and distributions, net		(15,720)						(15,720)
Net change in unrealized gains and losses on AFS securities, net of tax		36,411				36,411	36,411
Amortization of unrealized holding gains on securities transferred from AFS to HTM, net of tax		(486)				(486)	(486)
Foreign currency translation adjustments, net of tax		2,024				2,024	2,024
Net change in unrealized gains and losses on cash flow hedges, net of tax		797				797	797
Share-based compensation, net		15,122		15,122			15,122
Common stock repurchases (in shares)			(488,578)
Common stock repurchases		(116,023)	$ (1)		(116,022)		(116,023)
Balance (in shares) at Mar. 31, 2019			52,322,105
Ending balance at Mar. 31, 2019		$ 5,483,823	$ 52	$ 1,394,130	$ 3,963,965	$ (15,374)	$ 5,342,773	$ 141,050

[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.