Noninterest Income - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 205,905	$ 130,437	$ 644,533	$ 364,258
Revenues outside the scope of ASC 606	88,104	79,633	263,602	194,019
Noninterest income	294,009	210,070	908,135	558,277
Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	145,521	123,782	439,178	343,559
Revenues outside the scope of ASC 606	15,508	11,446	32,314	33,761
Noninterest income	161,029	135,228	471,492	377,320
SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	633	630	1,834	1,693
Revenues outside the scope of ASC 606	1	(25)	(5)	(16)
Noninterest income	634	605	1,829	1,677
SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,063	5,479	20,050	17,144
Revenues outside the scope of ASC 606	27,892	18,944	79,810	64,688
Noninterest income	34,955	24,423	99,860	81,832
SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	52,221		182,059
Revenues outside the scope of ASC 606	726		6,005
Noninterest income	52,947		188,064
Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	467	546	1,412	1,862
Revenues outside the scope of ASC 606	43,977	49,268	145,478	95,586
Noninterest income	44,444	49,814	146,890	97,448
Client investment fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	46,679	36,265	136,905	88,592
Client investment fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	46,171	35,845	135,551	87,491
Client investment fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	508	420	1,354	1,101
Client investment fees | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Client investment fees | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Client investment fees | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Spot contract commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	36,836	30,041	106,561	92,791
Spot contract commissions | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	36,644	29,776	105,877	92,098
Spot contract commissions | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	89	184	376	507
Spot contract commissions | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Spot contract commissions | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Spot contract commissions | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	103	81	308	186
Card interchange fees, gross
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	35,048	34,013	115,986	95,399
Card interchange fees, gross | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	34,867	33,905	115,468	95,088
Card interchange fees, gross | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Card interchange fees, gross | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Card interchange fees, gross | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Card interchange fees, gross | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	181	108	518	311
Merchant service fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,943	3,679	12,764	10,010
Merchant service fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,943	3,677	12,764	10,008
Merchant service fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	2	0	2
Merchant service fees | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Merchant service fees | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Merchant service fees | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Deposit service charges
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22,482	19,588	65,496	56,081
Deposit service charges | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22,263	19,207	64,806	54,633
Deposit service charges | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	36	24	104	83
Deposit service charges | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Deposit service charges | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Deposit service charges | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	183	357	586	1,365
Investment banking revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	38,516		137,005
Investment banking revenue | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Investment banking revenue | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Investment banking revenue | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Investment banking revenue | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	38,516		137,005
Investment banking revenue | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12,275		40,812
Commissions | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Commissions | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Commissions | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Commissions | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12,275		40,812
Commissions | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Fund management fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,493	5,479	24,292	17,144
Fund management fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Fund management fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Fund management fees | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,063	5,479	20,050	17,144
Fund management fees | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,430		4,242
Fund management fees | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Correspondent bank rebates
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,633	1,372	4,712	4,241
Correspondent bank rebates | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,633	1,372	4,712	4,241
Correspondent bank rebates | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Correspondent bank rebates | SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Correspondent bank rebates | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0		0
Correspondent bank rebates | Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 0	$ 0	$ 0	$ 0