Noninterest Income - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 221,371	$ 122,459	$ 438,628	$ 233,821
Revenues outside the scope of ASC 606	112,379	70,230	175,498	114,386
Noninterest income	333,750	192,689	614,126	348,207
Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	122,288	98,263	240,161	190,276
Revenues outside the scope of ASC 606	8,364	13,411	16,808	19,284
Noninterest income	130,652	111,674	256,969	209,560
SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	664	554	1,202	1,063
Revenues outside the scope of ASC 606	22	11	(6)	9
Noninterest income	686	565	1,196	1,072
SVB Capital
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,328	5,929	12,987	11,665
Revenues outside the scope of ASC 606	33,731	23,460	51,917	47,698
Noninterest income	40,059	29,389	64,904	59,363
SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	64,553		129,838
Revenues outside the scope of ASC 606	2,447		5,279
Noninterest income	67,000		135,117
Other Items
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	27,538	17,713	54,440	30,817
Revenues outside the scope of ASC 606	67,815	33,348	101,500	47,395
Noninterest income	95,353	51,061	155,940	78,212
Client investment fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	45,744	29,452	90,226	52,327
Client investment fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18,325	11,895	35,884	22,145
Client investment fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	466	379	846	681
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	26,953	17,178	53,496	29,501
Spot contract commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	34,696	31,548	69,725	62,750
Spot contract commissions | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	34,428	31,350	69,233	62,322
Spot contract commissions | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	165	144	288	323
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	54	204	105
Card interchange fees, gross
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	42,077	31,838	80,938	61,386
Card interchange fees, gross | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	41,887	31,734	80,601	61,183
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	190	104	337	203
Merchant service fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,286	3,425	8,821	6,331
Merchant service fees | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,286	3,425	8,821	6,331
Merchant service fees | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
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	22,075	18,794	43,014	36,493
Deposit service charges | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	21,750	18,386	42,543	35,426
Deposit service charges | SVB Private Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	33	31	68	59
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	292	377	403	1,008
Investment banking revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	48,694		98,489
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	48,694		98,489
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	14,429		28,537
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	14,429		28,537
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	7,758	5,929	15,799	11,665
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	6,328	5,929	12,987	11,665
Fund management fees | SVB Leerink
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,430		2,812
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	1,612	1,473	3,079	2,869
Correspondent bank rebates | Global Commercial Bank
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,612	1,473	3,079	2,869
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