Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income before noncontrolling interests	$ 1,294,294	$ 1,184,717	$ 1,011,348
Change in foreign currency cumulative translation gains and losses:
Foreign currency translation gains (losses)	16,467	3,208	(5,999)
Related tax (expense) benefit	(4,621)	(889)	1,669
Change in unrealized gains and losses on available-for-sale securities:
Unrealized holding gains (losses)	606,038	189,813	(22,348)
Related tax (expense) benefit	(168,521)	(52,697)	6,315
Reclassification adjustment for (gains) losses included in net income	(61,165)	3,905	740
Related tax expense (benefit)	16,953	(1,087)	(205)
Reclassification of unrealized gains on equity securities to retained earnings for ASU 2016-01	0	0	(40,316)
Related tax expense	0	0	11,145
Amortization of unrealized holding losses (gains) on securities transferred from available-for-sale to held-to-maturity	2,104	(2,158)	(4,607)
Related tax (expense) benefit	(586)	600	1,277
Reclassification of stranded tax effect to retained earnings for ASU 2018-02	0	0	(319)
Change in unrealized gains and losses on cash flow hedges:
Unrealized gains (losses)	231,920	(8,305)	0
Related tax (expenses) benefit	(64,281)	2,306	0
Reclassification adjustment for (gains) losses included in net income	(49,928)	5,358	0
Related tax expense (benefit)	13,692	(1,489)	0
Other comprehensive income (loss), net of tax	538,072	138,565	(52,648)
Comprehensive income	1,832,366	1,323,282	958,700
Comprehensive income attributable to noncontrolling interests	(85,926)	(47,861)	(37,508)
Comprehensive income attributable to SVBFG	$ 1,746,440	$ 1,275,421	$ 921,192