Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Net interest income (loss)	$ 527,740	$ 520,644	$ 1,564,804	$ 1,562,933
Provision for credit losses	52,018	(36,536)	(257,943)	(89,033)
Noninterest income	547,583	294,009	1,218,365	908,135
Noninterest expense	(491,021)	(391,324)	(1,370,242)	(1,140,510)
Income before income tax expense	636,320	386,793	1,154,984	1,241,525
Total average loans, amortized cost	37,318,600	29,822,426	35,835,927	29,210,960
Total average assets	88,348,366	65,327,748	79,760,650	61,214,132
Total average deposits	77,680,016	57,234,969	69,166,064	53,331,344
Global Commercial Bank
Segment Reporting Information [Line Items]
Noninterest income	147,594	161,029	447,902	471,492
SVB Private Bank
Segment Reporting Information [Line Items]
Noninterest income	916	634	2,486	1,829
SVB Capital
Segment Reporting Information [Line Items]
Noninterest income	60,380	34,955	86,748	99,860
SVB Leerink
Segment Reporting Information [Line Items]
Noninterest income	113,651	52,947	340,145	188,064
Operating segments | Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income (loss)	512,963	455,161	1,461,768	1,360,997
Provision for credit losses	37,847	(34,075)	(200,020)	(79,175)
Noninterest income	147,594	161,029	447,902	471,492
Noninterest expense	(258,035)	(213,786)	(724,233)	(617,933)
Income before income tax expense	440,369	368,329	985,417	1,135,381
Total average loans, amortized cost	30,763,715	25,839,647	30,126,870	25,457,997
Total average assets	77,802,730	58,384,473	69,212,733	54,196,976
Total average deposits	74,825,725	55,250,154	66,408,359	51,352,644
Operating segments | SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income (loss)	19,145	12,772	52,952	37,200
Provision for credit losses	14,881	(1,910)	(44,194)	(1,779)
Noninterest income	916	634	2,486	1,829
Noninterest expense	(12,293)	(11,638)	(32,547)	(30,015)
Income before income tax expense	22,649	(142)	(21,303)	7,235
Total average loans, amortized cost	4,263,324	3,400,889	4,053,018	3,235,943
Total average assets	4,297,011	3,431,313	4,087,786	3,264,071
Total average deposits	2,163,903	1,497,303	2,069,196	1,461,170
Operating segments | SVB Capital
Segment Reporting Information [Line Items]
Net interest income (loss)	2	9	28	20
Provision for credit losses		0	0	0
Noninterest income	60,380	34,955	86,748	99,860
Noninterest expense	(11,198)	(8,129)	(28,040)	(21,794)
Income before income tax expense	49,184	26,835	58,736	78,086
Total average loans, amortized cost	0	0	0	0
Total average assets	413,882	396,031	430,391	382,707
Total average deposits	0	0	0	0
Operating segments | SVB Leerink
Segment Reporting Information [Line Items]
Net interest income (loss)	175	277	373	961
Provision for credit losses		0	0	0
Noninterest income	113,651	52,947	340,145	188,064
Noninterest expense	(77,567)	(55,200)	(248,254)	(177,675)
Income before income tax expense	36,259	(1,976)	92,264	11,350
Total average loans, amortized cost	0	0	0	0
Total average assets	605,263	428,848	514,836	380,290
Total average deposits	0	0	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income (loss)	(4,545)	52,425	49,683	163,755
Provision for credit losses	(710)	(551)	(13,729)	(8,079)
Noninterest income	225,042	44,444	341,084	146,890
Noninterest expense	(131,928)	(102,571)	(337,168)	(293,093)
Income before income tax expense	87,859	(6,253)	39,870	9,473
Total average loans, amortized cost	2,291,561	581,890	1,656,039	517,020
Total average assets	5,229,480	2,687,083	5,514,904	2,990,088
Total average deposits	$ 690,388	$ 487,512	$ 688,509	$ 517,530