Interim Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income before noncontrolling interests	$ 291,612	$ 208,026
Change in foreign currency cumulative translation gains and losses:
Foreign currency translation gains	2,806	3,106
Related tax expense	(782)	(856)
Change in unrealized gains and losses on available-for-sale securities:
Unrealized holding gains (losses)	46,836	(58,027)
Related tax (expense) benefit	(13,045)	15,926
Reclassification adjustment for losses included in net income	3,630	0
Related tax benefit	(1,010)	0
Reclassification of unrealized gains on equity securities to retained earnings for ASU 2016-01	0	(40,316)
Related tax expense	0	11,145
Amortization of unrealized holding gains on securities transferred from available-for-sale to held-to-maturity	(674)	(1,206)
Related tax benefit	188	333
Reclassification of stranded tax effect to retained earnings for ASU 2018-02	0	(319)
Change in unrealized gains and losses on cash flow hedges:
Unrealized gains	1,102	0
Related tax expense	(307)	0
Reclassification adjustment for losses included in net income	3	0
Related tax benefit	(1)	0
Other comprehensive income (loss), net of tax	38,746	(70,214)
Comprehensive income	330,358	137,812
Comprehensive income attributable to noncontrolling interests	(2,880)	(13,065)
Comprehensive income attributable to SVBFG	$ 327,478	$ 124,747