Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Credit Quality Indicators, Broken out by Risk-Based Segments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	$ 45,181,488	$ 33,164,636
Loans, at gross basis		33,327,704
Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	104,244
Loans, at gross basis		102,669
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	43,825,846
Loans, at gross basis		32,361,879
Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,251,398
Loans, at gross basis		863,156
Global fund banking
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	25,543,198	17,696,794
Loans, at gross basis		17,712,797
Global fund banking | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	11
Loans, at gross basis		0
Global fund banking | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	25,537,354
Loans, at gross basis		17,708,550
Global fund banking | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	5,833
Loans, at gross basis		4,247
Investor dependent
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	4,971,818	4,335,195
Loans, at gross basis		4,418,884
Investor dependent | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	51,053
Loans, at gross basis		34,719
Investor dependent | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	4,454,347
Loans, at gross basis		3,850,585
Investor dependent | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	466,418
Loans, at gross basis		533,580
Investor dependent | Early stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,485,866	1,624,221
Loans, at gross basis		1,653,425
Investor dependent | Early stage | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	18,340
Loans, at gross basis		11,093
Investor dependent | Early stage | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,288,897
Loans, at gross basis		1,436,022
Investor dependent | Early stage | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	178,629
Loans, at gross basis		206,310
Investor dependent | Mid stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,564,870	1,047,398
Loans, at gross basis		1,066,783
Investor dependent | Mid stage | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	4,056
Loans, at gross basis		17,330
Investor dependent | Mid stage | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,420,788
Loans, at gross basis		924,002
Investor dependent | Mid stage | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	140,026
Loans, at gross basis		125,451
Investor dependent | Later stage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,921,082	1,663,576
Loans, at gross basis		1,698,676
Investor dependent | Later stage | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	28,657
Loans, at gross basis		6,296
Investor dependent | Later stage | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,744,662
Loans, at gross basis		1,490,561
Investor dependent | Later stage | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	147,763
Loans, at gross basis		201,819
Cash flow dependent
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	4,934,533	4,424,238
Loans, at gross basis		4,455,867
Cash flow dependent | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	46,000
Loans, at gross basis		62,266
Cash flow dependent | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	4,473,343
Loans, at gross basis		4,181,613
Cash flow dependent | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	415,190
Loans, at gross basis		211,988
Cash flow dependent | Sponsor led buyout
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,989,173	2,185,497
Loans, at gross basis		2,203,020
Cash flow dependent | Sponsor led buyout | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	39,996
Loans, at gross basis		44,585
Cash flow dependent | Sponsor led buyout | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,795,972
Loans, at gross basis		2,039,847
Cash flow dependent | Sponsor led buyout | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	153,205
Loans, at gross basis		118,588
Cash flow dependent | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	2,945,360	2,238,741
Loans, at gross basis		2,252,847
Cash flow dependent | Other | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	6,004
Loans, at gross basis		17,681
Cash flow dependent | Other | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	2,677,371
Loans, at gross basis		2,141,766
Cash flow dependent | Other | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	261,985
Loans, at gross basis		93,400
Private Bank
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	4,901,056	3,492,269
Loans, at gross basis		3,489,219
Private Bank | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	6,152
Loans, at gross basis		5,480
Private Bank | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	4,862,176
Loans, at gross basis		3,472,138
Private Bank | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	32,728
Loans, at gross basis		11,601
Balance sheet dependent
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	2,191,023	1,286,153
Loans, at gross basis		1,297,304
Balance sheet dependent | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	0
Loans, at gross basis		0
Balance sheet dependent | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	2,104,645
Loans, at gross basis		1,231,961
Balance sheet dependent | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	86,378
Loans, at gross basis		65,343
Premium wine
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,052,643	1,062,264
Loans, at gross basis		1,063,512
Premium wine | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	998
Loans, at gross basis		204
Premium wine | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	910,397
Loans, at gross basis		1,026,973
Premium wine | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	141,248
Loans, at gross basis		36,335
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	27,687	867,723
Loans, at gross basis		890,121
Other | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	30
Loans, at gross basis		0
Other | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	27,594
Loans, at gross basis		890,059
Other | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	63
Loans, at gross basis		62
SBA loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,559,530	$ 0
SBA loans | Nonperforming (Nonaccrual)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	0
SBA loans | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	1,455,990
SBA loans | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, amortized cost	$ 103,540