Loans and Allowance for Loan Losses Activity in Allowance for Loan Losses Broken out by Portfolio Segment (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	$ 110,651	$ 89,947	$ 82,627
Charge-offs	(42,666)	(33,319)	(23,904)
Recoveries	11,208	9,693	25,123
Provision for (Reduction of)	63,693	44,330	6,101
Ending Balance	142,886	110,651	89,947
Hardware
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	29,761	16,810	14,688
Charge-offs	(18,819)	(20,247)	(4,828)
Recoveries	2,677	1,107	455
Provision for (Reduction of)	22,934	32,091	6,495
Ending Balance	36,553	29,761	16,810
Software
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	42,648	38,263	29,288
Charge-offs	(8,861)	(4,316)	(10,252)
Recoveries	1,934	4,874	11,659
Provision for (Reduction of)	28,363	3,827	7,568
Ending Balance	64,084	42,648	38,263
Venture capital/private equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	9,963	7,319	8,241
Charge-offs	0	0	0
Recoveries	0	0	0
Provision for (Reduction of)	6,422	2,644	(922)
Ending Balance	16,385	9,963	7,319
Life science
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	13,606	10,243	9,077
Charge-offs	(6,010)	(5,080)	(4,201)
Recoveries	1,860	334	6,644
Provision for (Reduction of)	2,470	8,109	(1,277)
Ending Balance	11,926	13,606	10,243
Premium wine
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	3,523	3,914	5,492
Charge-offs	0	(584)	(449)
Recoveries	170	650	1,223
Provision for (Reduction of)	221	(457)	(2,352)
Ending Balance	3,914	3,523	3,914
Commercial, Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	3,912	5,817	5,318
Charge-offs	(8,107)	(2,485)	(3,954)
Recoveries	2,995	1,377	471
Provision for (Reduction of)	4,880	(797)	3,982
Ending Balance	3,680	3,912	5,817
Commercial loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	103,413	82,366	72,104
Charge-offs	(41,797)	(32,712)	(23,684)
Recoveries	9,636	8,342	20,452
Provision for (Reduction of)	65,290	45,417	13,494
Ending Balance	136,542	103,413	82,366
Consumer loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	7,238	7,581	10,523
Charge-offs	(869)	(607)	(220)
Recoveries	1,572	1,351	4,671
Provision for (Reduction of)	(1,597)	(1,087)	(7,393)
Ending Balance	$ 6,344	$ 7,238	$ 7,581