Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Credit Quality Indicators, Broken out by Risk-Based Segments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	$ 47,675,166	$ 45,181,488
Loans, at gross basis		45,181,488
Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	90,247
Loans, at gross basis		104,244
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	46,348,701
Loans, at gross basis		43,825,846
Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,236,218
Loans, at gross basis		1,251,398
Global fund banking
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	27,306,926	25,543,198
Loans, at gross basis		25,543,198
Global fund banking | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	18	11
Loans, at gross basis		11
Global fund banking | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	27,292,491	25,537,354
Loans, at gross basis		25,537,354
Global fund banking | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	14,417	5,833
Loans, at gross basis		5,833
Investor dependent
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	5,167,069	4,971,818
Loans, at gross basis		4,971,818
Investor dependent | Early stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,523,208	1,485,866
Loans, at gross basis		1,485,866
Investor dependent | Mid stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,588,185	1,564,870
Loans, at gross basis		1,564,870
Investor dependent | Later stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	2,055,676	1,921,082
Loans, at gross basis		1,921,082
Investor dependent | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	35,169
Loans, at gross basis		51,053
Investor dependent | Nonperforming (Nonaccrual) | Early stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	7,766	18,340
Loans, at gross basis		18,340
Investor dependent | Nonperforming (Nonaccrual) | Mid stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	0	4,056
Loans, at gross basis		4,056
Investor dependent | Nonperforming (Nonaccrual) | Later stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	27,403	28,657
Loans, at gross basis		28,657
Investor dependent | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	4,717,953
Loans, at gross basis		4,454,347
Investor dependent | Pass | Early stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,303,581	1,288,897
Loans, at gross basis		1,288,897
Investor dependent | Pass | Mid stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,492,157	1,420,788
Loans, at gross basis		1,420,788
Investor dependent | Pass | Later stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,922,215	1,744,662
Loans, at gross basis		1,744,662
Investor dependent | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	413,947
Loans, at gross basis		466,418
Investor dependent | Criticized | Early stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	211,861	178,629
Loans, at gross basis		178,629
Investor dependent | Criticized | Mid stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	96,028	140,026
Loans, at gross basis		140,026
Investor dependent | Criticized | Later stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	106,058	147,763
Loans, at gross basis		147,763
Cash flow dependent
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	4,944,176	4,934,533
Loans, at gross basis		4,934,533
Cash flow dependent | Sponsor led buyout
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,984,567	1,989,173
Loans, at gross basis		1,989,173
Cash flow dependent | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	2,959,609	2,945,360
Loans, at gross basis		2,945,360
Cash flow dependent | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	45,476
Loans, at gross basis		46,000
Cash flow dependent | Nonperforming (Nonaccrual) | Sponsor led buyout
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	39,848	39,996
Loans, at gross basis		39,996
Cash flow dependent | Nonperforming (Nonaccrual) | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	5,628	6,004
Loans, at gross basis		6,004
Cash flow dependent | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	4,524,529
Loans, at gross basis		4,473,343
Cash flow dependent | Pass | Sponsor led buyout
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,844,415	1,795,972
Loans, at gross basis		1,795,972
Cash flow dependent | Pass | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	2,680,114	2,677,371
Loans, at gross basis		2,677,371
Cash flow dependent | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	374,171
Loans, at gross basis		415,190
Cash flow dependent | Criticized | Sponsor led buyout
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	100,304	153,205
Loans, at gross basis		153,205
Cash flow dependent | Criticized | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	273,867	261,985
Loans, at gross basis		261,985
SVB Private Bank
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	5,063,827	4,901,056
Loans, at gross basis		4,901,056
SVB Private Bank | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	8,445	6,152
Loans, at gross basis		6,152
SVB Private Bank | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	5,024,735	4,862,176
Loans, at gross basis		4,862,176
SVB Private Bank | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	30,647	32,728
Loans, at gross basis		32,728
Balance sheet dependent
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	2,501,524	2,191,023
Loans, at gross basis		2,191,023
Balance sheet dependent | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	0	0
Loans, at gross basis		0
Balance sheet dependent | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	2,373,152	2,104,645
Loans, at gross basis		2,104,645
Balance sheet dependent | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	128,372	86,378
Loans, at gross basis		86,378
Premium wine
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,040,223	1,052,643
Loans, at gross basis		1,052,643
Premium wine | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,139	998
Loans, at gross basis		998
Premium wine | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	903,583	910,397
Loans, at gross basis		910,397
Premium wine | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	135,501	141,248
Loans, at gross basis		141,248
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	45,688	27,687
Loans, at gross basis		27,687
Other | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	0	30
Loans, at gross basis		30
Other | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	45,653	27,594
Loans, at gross basis		27,594
Other | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	35	63
Loans, at gross basis		63
SBA loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,605,733	1,559,530
SBA loans | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	0	0
SBA loans | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	1,466,605	1,455,990
SBA loans | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, at amortized cost	$ 139,128	$ 103,540