Employee Compensation and Benefit Plans - Expenses Incurred Under Certain Employee Compensation and Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Incentive Compensation Plan	$ 193,004	$ 143,888	$ 160,293
Direct Drive Incentive Compensation Plan	37,681	37,315	40,578
Retention Program	0	2,438	1,438
Warrant Incentive Plan	33,921	14,881	9,112
SVBFG 401(k) Plan	29,939	25,687	21,323
SVBFG ESOP	5,807	4,197	6,435
SVB Leerink
Segment Reporting Information [Line Items]
Incentive Compensation Plan	233,145	106,871	0
Retention Award	$ 12,991	$ 12,015	$ 0