Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net interest income	$ 524,137	$ 512,886
Provision for credit losses	(243,480)	(28,551)
Noninterest income	301,934	280,376
Noninterest expense	(399,585)	(365,664)
Income before income tax expense	183,006	399,047
Total average loans, amortized cost	33,660,728	28,388,072
Total average assets	72,407,168	57,528,437
Total average deposits	61,808,231	49,714,209
Global Commercial Bank
Segment Reporting Information [Line Items]
Noninterest income	166,834	152,861
SVB Private Bank
Segment Reporting Information [Line Items]
Noninterest income	900	510
SVB Capital
Segment Reporting Information [Line Items]
Noninterest income	4,918	24,845
SVB Leerink
Segment Reporting Information [Line Items]
Noninterest income	62,677	68,117
Operating segments | Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income	463,835	445,876
Provision for credit losses	(194,411)	(26,805)
Noninterest income	166,834	152,861
Noninterest expense	(224,855)	(198,683)
Income before income tax expense	211,403	373,249
Total average loans, amortized cost	29,137,484	24,798,197
Total average assets	61,813,129	50,132,098
Total average deposits	59,217,433	47,596,868
Operating segments | SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income	15,164	11,981
Provision for credit losses	(54,490)	984
Noninterest income	900	510
Noninterest expense	(10,090)	(7,414)
Income before income tax expense	(48,516)	6,061
Total average loans, amortized cost	3,857,478	3,085,883
Total average assets	3,892,400	3,109,275
Total average deposits	1,922,663	1,491,234
Operating segments | SVB Capital
Segment Reporting Information [Line Items]
Net interest income	21	6
Provision for credit losses	0	0
Noninterest income	4,918	24,845
Noninterest expense	(8,585)	(5,782)
Income before income tax expense	(3,646)	19,069
Total average loans, amortized cost	0	0
Total average assets	447,201	378,732
Total average deposits	0	0
Operating segments | SVB Leerink
Segment Reporting Information [Line Items]
Net interest income	201	442
Provision for credit losses	0	0
Noninterest income	62,677	68,117
Noninterest expense	(62,037)	(60,540)
Income before income tax expense	841	8,019
Total average loans, amortized cost	0	0
Total average assets	483,648	300,332
Total average deposits	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income	44,916	54,581
Provision for credit losses	5,421	(2,730)
Noninterest income	66,605	34,043
Noninterest expense	(94,018)	(93,245)
Income before income tax expense	22,924	(7,351)
Total average loans, amortized cost	665,766	503,992
Total average assets	5,770,790	3,608,000
Total average deposits	$ 668,135	$ 626,107