Noninterest Income - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									$ 511,656
Revenue not from contracts with customer									233,328
Noninterest income	$ 186,707	$ 210,070	$ 192,689	$ 155,518	$ 152,266	$ 158,778	$ 128,528	$ 117,659	744,984	$ 557,231	$ 456,552
Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									408,263
Revenue not from contracts with customer									36,384
Noninterest income									444,647
SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,329
Revenue not from contracts with customer									(48)
Noninterest income									2,281
SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									23,016
Revenue not from contracts with customer									78,165
Noninterest income									101,181
Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									78,048
Revenue not from contracts with customer									118,827
Noninterest income									196,875
Spot contract commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									127,459	104,344	89,354
Spot contract commissions | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									126,445
Spot contract commissions | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									691
Spot contract commissions | SVB Capital
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									323
Card interchange fees, gross
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									134,502
Card interchange fees, gross | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									134,074
Card interchange fees, gross | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Card interchange fees, gross | SVB Capital
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									428
Merchant service fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									14,420
Merchant service fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									14,415
Merchant service fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									4
Merchant service fees | SVB Capital
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									1
Deposit service charges
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									76,097
Deposit service charges | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									74,348
Deposit service charges | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									108
Deposit service charges | SVB Capital
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									1,641
Client investment fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									130,360	$ 56,136	$ 32,219
Client investment fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									53,179
Client investment fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,526
Client investment fees | SVB Capital
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									75,655
Fund management fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									23,016
Fund management fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Fund management fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Fund management fees | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									23,016
Fund management fees | Other Income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Correspondent bank rebates
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									5,802
Correspondent bank rebates | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									5,802
Correspondent bank rebates | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Correspondent bank rebates | SVB Capital
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