Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net interest income (loss)	$ 512,927	$ 529,403	$ 1,037,064	$ 1,042,289
Provision for credit losses	(66,481)	(23,946)	(309,961)	(52,497)
Noninterest income (7)	368,848	333,750	670,782	614,126
Noninterest expense	(479,636)	(383,522)	(879,221)	(749,186)
Income before income tax expense	335,658	455,685	518,664	854,732
Total average loans, amortized cost	36,512,159	29,406,620	35,086,444	28,900,160
Total average assets	78,432,002	60,700,486	75,419,585	59,123,234
Total average deposits	67,916,381	52,962,208	64,862,306	51,347,180
Global Commercial Bank
Segment Reporting Information [Line Items]
Noninterest income (7)	133,474	157,605	300,308	310,465
SVB Private Bank
Segment Reporting Information [Line Items]
Noninterest income (7)	670	686	1,570	1,196
SVB Capital
Segment Reporting Information [Line Items]
Noninterest income (7)	21,450	40,059	26,368	64,904
SVB Leerink
Segment Reporting Information [Line Items]
Noninterest income (7)	163,817	67,000	226,494	135,117
Operating segments | Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income (loss)	484,969	461,752	948,805	907,628
Provision for credit losses	(43,456)	(18,295)	(237,867)	(45,100)
Noninterest income (7)	133,474	157,605	300,308	310,465
Noninterest expense	(241,343)	(206,902)	(466,198)	(404,147)
Income before income tax expense	333,644	394,160	545,048	768,846
Total average loans, amortized cost	30,472,414	25,724,704	29,804,949	25,264,010
Total average assets	67,936,486	53,965,699	64,870,536	52,068,609
Total average deposits	65,090,982	51,126,806	62,153,426	49,371,589
Operating segments | SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income (loss)	18,644	12,277	33,808	24,258
Provision for credit losses	(4,585)	(853)	(59,075)	131
Noninterest income (7)	670	686	1,570	1,196
Noninterest expense	(10,164)	(9,526)	(20,254)	(18,378)
Income before income tax expense	4,565	2,584	(43,951)	7,207
Total average loans, amortized cost	4,035,940	3,217,597	3,946,709	3,152,104
Total average assets	4,071,648	3,247,557	3,982,024	3,179,064
Total average deposits	2,119,983	1,394,905	2,021,323	1,442,803
Operating segments | SVB Capital
Segment Reporting Information [Line Items]
Net interest income (loss)	5	6	26	12
Provision for credit losses		0	0	0
Noninterest income (7)	21,450	40,059	26,368	64,904
Noninterest expense	(8,256)	(7,883)	(16,842)	(13,665)
Income before income tax expense	13,199	32,182	9,552	51,251
Total average loans, amortized cost	0	0	0	0
Total average assets	430,272	373,167	438,737	375,934
Total average deposits	0	0	0	0
Operating segments | SVB Leerink
Segment Reporting Information [Line Items]
Net interest income (loss)	(3)	242	198	684
Provision for credit losses		0	0	0
Noninterest income (7)	163,817	67,000	226,494	135,117
Noninterest expense	(108,650)	(61,935)	(170,687)	(122,475)
Income before income tax expense	55,164	5,307	56,005	13,326
Total average loans, amortized cost	0	0	0	0
Total average assets	454,603	410,279	469,126	355,609
Total average deposits	0	0	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income (loss)	9,312	55,126	54,227	109,707
Provision for credit losses	(18,440)	(4,798)	(13,019)	(7,528)
Noninterest income (7)	49,437	68,400	116,042	102,444
Noninterest expense	(111,223)	(97,276)	(205,240)	(190,521)
Income before income tax expense	(70,914)	21,452	(47,990)	14,102
Total average loans, amortized cost	2,003,805	464,319	1,334,786	484,046
Total average assets	5,538,993	2,703,784	5,659,162	3,144,018
Total average deposits	$ 705,416	$ 440,497	$ 687,557	$ 532,788