Noninterest Income - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									$ 880,951	$ 511,656
Revenue not from contracts with customer									340,528	233,328
Noninterest income	$ 313,344	$ 294,009	$ 333,750	$ 280,376	$ 186,707	$ 210,070	$ 192,689	$ 155,518	1,221,479	744,984	$ 557,231
Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									592,185	483,918
Revenue not from contracts with customer									45,737	36,384
Noninterest income									637,922	520,302
SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,563	2,329
Revenue not from contracts with customer									803	(48)
Noninterest income									3,366	2,281
SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									26,850	23,016
Revenue not from contracts with customer									95,544	78,165
Noninterest income									122,394	101,181
SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									257,195
Revenue not from contracts with customer									7,321
Noninterest income									264,516
Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,158	2,393
Revenue not from contracts with customer									191,123	118,827
Noninterest income									193,281	121,220
Client investment fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									182,068	130,360	56,136
Client investment fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									180,152	128,834
Client investment fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,916	1,526
Client investment fees | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Client investment fees | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Client investment fees | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Spot contract commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									145,915	127,459	104,344
Spot contract commissions | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									144,930	126,445
Spot contract commissions | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									510	691
Spot contract commissions | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Spot contract commissions | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Spot contract commissions | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									475	323
Card interchange fees, gross
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									154,953	134,502
Card interchange fees, gross | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									154,197	134,074
Card interchange fees, gross | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Card interchange fees, gross | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Card interchange fees, gross | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Card interchange fees, gross | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									756	428
Merchant service fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									18,355	14,420
Merchant service fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									18,355	14,415
Merchant service fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	4
Merchant service fees | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Merchant service fees | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Merchant service fees | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	1
Deposit service charges
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									89,200	76,097
Deposit service charges | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									88,136	74,348
Deposit service charges | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									137	108
Deposit service charges | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Deposit service charges | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Deposit service charges | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									927	1,641
Investment banking revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									195,177
Investment banking revenue | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Investment banking revenue | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Investment banking revenue | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Investment banking revenue | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									195,177
Investment banking revenue | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									56,346
Commissions | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Commissions | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Commissions | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Commissions | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									56,346
Commissions | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Fund management fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									32,522	23,016	$ 21,214
Fund management fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Fund management fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Fund management fees | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									26,850	23,016
Fund management fees | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									5,672
Fund management fees | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Correspondent bank rebates
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									6,415	5,802
Correspondent bank rebates | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									6,415	5,802
Correspondent bank rebates | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Correspondent bank rebates | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
Correspondent bank rebates | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Correspondent bank rebates | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									$ 0	$ 0