Interim Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income before noncontrolling interests	$ 336,571	$ 247,026	$ 628,183	$ 455,052
Change in foreign currency cumulative translation gains and losses:
Foreign currency translation losses	(2,900)	(5,184)	(94)	(2,078)
Related tax benefit	808	1,433	26	577
Change in unrealized gains and losses on available-for-sale securities:
Unrealized holding gains (losses)	119,182	(15,103)	166,018	(73,130)
Related tax (expense) benefit	(33,194)	4,349	(46,239)	20,275
Reclassification adjustment for losses included in net income	275	0	3,905	0
Related tax benefit	(77)	0	(1,087)	0
Reclassification of unrealized gains on equity securities to retained earnings for ASU 2016-01	0	0	0	(40,316)
Related tax expense	0	0	0	11,145
Amortization of unrealized holding gains on securities transferred from available-for-sale to held-to-maturity	(719)	(932)	(1,393)	(2,138)
Related tax benefit	200	258	388	591
Reclassification of stranded tax effect to retained earnings for ASU 2018-02	0	0	0	(319)
Change in unrealized gains and losses on cash flow hedges:
Unrealized gains	17,554	0	18,656	0
Related tax expense	(4,890)	0	(5,197)	0
Reclassification adjustment for losses included in net income	508	0	511	0
Related tax benefit	(141)	0	(142)	0
Other comprehensive income (loss), net of tax	96,606	(15,179)	135,352	(85,393)
Comprehensive income	433,177	231,847	763,535	369,659
Comprehensive income attributable to noncontrolling interests	(18,584)	(9,228)	(21,464)	(22,293)
Comprehensive income attributable to SVBFG	$ 414,593	$ 222,619	$ 742,071	$ 347,366