Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Activity in Allowance for Loan Losses Broken out by Portfolio Segment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	$ 280,903	$ 255,024	$ 225,366
Charge-offs	(92,603)	(67,917)	(66,682)
Recoveries	21,038	11,636	8,538
Provision for (Reduction of) Loan Losses	94,183	84,292	85,939
Foreign Currency Translation Adjustments	1,403	(2,132)	1,863
Ending Balance	304,924	280,903	255,024
Commercial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	260,966	238,583	213,182
Charge-offs	(91,572)	(67,628)	(65,115)
Recoveries	20,782	11,149	7,175
Provision for (Reduction of) Loan Losses	91,814	80,953	81,553
Foreign Currency Translation Adjustments	1,428	(2,091)	1,788
Ending Balance	283,418	260,966	238,583
Commercial loans \| Software/internet
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	103,567	96,104	97,388
Charge-offs	(46,930)	(42,315)	(45,012)
Recoveries	11,363	5,664	4,649
Provision for (Reduction of) Loan Losses	31,766	45,068	38,462
Foreign Currency Translation Adjustments	457	(954)	617
Ending Balance	100,223	103,567	96,104
Commercial loans \| Hardware
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	19,725	27,614	31,166
Charge-offs	(10,056)	(16,148)	(10,414)
Recoveries	7,069	1,849	487
Provision for (Reduction of) Loan Losses	2,740	6,555	6,051
Foreign Currency Translation Adjustments	166	(145)	324
Ending Balance	19,644	19,725	27,614
Commercial loans \| Private equity/venture capital
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	98,581	82,468	50,299
Charge-offs	(2,047)	(112)	(323)
Recoveries	2,047	13	0
Provision for (Reduction of) Loan Losses	16,989	16,485	31,625
Foreign Currency Translation Adjustments	235	(273)	867
Ending Balance	115,805	98,581	82,468
Commercial loans \| Life science/healthcare
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	32,180	24,924	25,446
Charge-offs	(31,950)	(6,662)	(8,210)
Recoveries	267	348	189
Provision for (Reduction of) Loan Losses	38,178	14,347	7,414
Foreign Currency Translation Adjustments	570	(777)	85
Ending Balance	39,245	32,180	24,924
Commercial loans \| Premium wine
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	3,355	3,532	4,115
Charge-offs	(174)	0	0
Recoveries	0	0	0
Provision for (Reduction of) Loan Losses	1,813	(182)	(540)
Foreign Currency Translation Adjustments	154	5	(43)
Ending Balance	5,148	3,355	3,532
Commercial loans \| Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	3,558	3,941	4,768
Charge-offs	(415)	(2,391)	(1,156)
Recoveries	36	3,275	1,850
Provision for (Reduction of) Loan Losses	328	(1,320)	(1,459)
Foreign Currency Translation Adjustments	(154)	53	(62)
Ending Balance	3,353	3,558	3,941
Consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	19,937	16,441	12,184
Charge-offs	(1,031)	(289)	(1,567)
Recoveries	256	487	1,363
Provision for (Reduction of) Loan Losses	2,369	3,339	4,386
Foreign Currency Translation Adjustments	(25)	(41)	75
Ending Balance	$ 21,506	$ 19,937	$ 16,441

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of gain (loss) from converting allowance reserve for credit loss to currency of reporting entity from amount denominated or measured in a different currency, which decreases (increases) the allowance for loan and lease losses.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of credit loss expense (reversal of expense) for financing receivable.

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