Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Net interest income	$ 659,579	$ 524,137
Provision for credit losses	(18,679)	(243,480)
Noninterest income	744,180	301,934
Noninterest expense	(636,001)	(399,585)
Income before income tax expense	749,079	183,006
Total average loans, amortized cost	46,281,476	33,660,728
Total average assets	124,814,608	72,407,168
Total average deposits	110,608,414	61,808,231
Global Commercial Bank
Segment Reporting Information [Line Items]
Noninterest income	158,671	166,834
SVB Private Bank
Segment Reporting Information [Line Items]
Noninterest income	998	900
SVB Capital
Segment Reporting Information [Line Items]
Noninterest income	68,594	4,918
SVB Leerink
Segment Reporting Information [Line Items]
Noninterest income	170,967	62,677
Operating segments | Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income	618,609	463,835
Provision for credit losses	(44,503)	(194,411)
Noninterest income	158,671	166,834
Noninterest expense	(277,763)	(224,855)
Income before income tax expense	455,014	211,403
Total average loans, amortized cost	39,286,744	29,137,484
Total average assets	108,927,856	61,813,129
Total average deposits	106,267,572	59,217,433
Operating segments | SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income	27,025	15,164
Provision for credit losses	8,567	(54,490)
Noninterest income	998	900
Noninterest expense	(12,958)	(10,090)
Income before income tax expense	23,632	(48,516)
Total average loans, amortized cost	4,977,080	3,857,478
Total average assets	5,028,004	3,892,400
Total average deposits	3,292,673	1,922,663
Operating segments | SVB Capital
Segment Reporting Information [Line Items]
Net interest income	2	21
Provision for credit losses	0	0
Noninterest income	68,594	4,918
Noninterest expense	(15,233)	(8,585)
Income before income tax expense	53,363	(3,646)
Total average loans, amortized cost	0	0
Total average assets	576,705	447,201
Total average deposits	0	0
Operating segments | SVB Leerink
Segment Reporting Information [Line Items]
Net interest income	166	201
Provision for credit losses	0	0
Noninterest income	170,967	62,677
Noninterest expense	(136,352)	(62,037)
Income before income tax expense	34,781	841
Total average loans, amortized cost	0	0
Total average assets	767,300	483,648
Total average deposits	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income	13,777	44,916
Provision for credit losses	17,257	5,421
Noninterest income	344,950	66,605
Noninterest expense	(193,695)	(94,018)
Income before income tax expense	182,289	22,924
Total average loans, amortized cost	2,017,652	665,766
Total average assets	9,514,743	5,770,790
Total average deposits	$ 1,048,169	$ 668,135