Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income before noncontrolling interests	$ 1,184,717	$ 1,011,348	$ 519,178
Change in foreign currency cumulative translation gains and losses:
Foreign currency translation gains (losses)	3,208	(5,999)	6,355
Related tax (expense) benefit	(889)	1,669	(2,587)
Change in unrealized gains and losses on available-for-sale securities:
Unrealized holding gains (losses)	189,813	(22,348)	(47,161)
Related tax (expense) benefit	(52,697)	6,315	19,282
Reclassification adjustment for losses included in net income	3,905	740	5,189
Related tax benefit	(1,087)	(205)	(2,098)
Reclassification of unrealized gains on equity securities to retained earnings for ASU 2016-01	0	(40,316)	0
Related tax expense	0	11,145	0
Amortization of unrealized gains on securities transferred from available-for-sale to held-to-maturity	(2,158)	(4,607)	(6,475)
Related tax benefit	600	1,277	2,593
Reclassification of stranded tax effect to retained earnings for ASU 2018-02	0	(319)	0
Change in unrealized gains and losses on cash flow hedges:
Unrealized losses	(8,305)	0	0
Related tax benefit	2,306	0	0
Reclassification adjustment for losses included in net income	5,358	0	0
Related tax benefit	(1,489)	0	0
Other comprehensive income (loss), net of tax	138,565	(52,648)	(24,902)
Comprehensive income	1,323,282	958,700	494,276
Comprehensive income attributable to noncontrolling interests	(47,861)	(37,508)	(28,672)
Comprehensive income attributable to SVBFG	$ 1,275,421	$ 921,192	$ 465,604