SVB Financial (SIVBQ) 10-K 28 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	SIVB
Entity Registrant Name	SVB FINANCIAL GROUP
Entity Central Index Key	719,739
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		52,874,188
Entity Public Float			$ 9,261,347,942

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 2,923,075	$ 2,545,750
Available-for-sale securities, at fair value (cost of $11,131,008 and $12,588,783, respectively)	11,120,664	12,620,411
Held-to-maturity securities, at cost (fair value of $12,548,280 and $8,376,138, respectively)	12,663,455	8,426,998
Non-marketable and other securities	651,053	622,552
Total investment securities	24,435,172	21,669,961
Loans, net of unearned income	23,106,316	19,899,944
Allowance for loan losses	(255,024)	(225,366)
Net loans	22,851,292	19,674,578
Premises and equipment, net of accumulated depreciation and amortization	128,682	120,683
Accrued interest receivable and other assets	876,246	672,688
Total assets	51,214,467	44,683,660
Liabilities:
Noninterest-bearing demand deposits	36,655,497	31,975,457
Interest-bearing deposits	7,598,578	7,004,411
Total deposits	44,254,075	38,979,868
Short-term borrowings	1,033,730	512,668
Other liabilities	911,755	618,383
Long-term debt	695,492	795,704
Total liabilities	46,895,052	40,906,623
Commitments and contingencies (Note 19 and Note 25)
SVBFG stockholders’ equity:
Preferred stock, $0.001 par value, 20,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.001 par value, 150,000,000 shares authorized; 52,835,188 shares and 52,254,074 shares outstanding, respectively	53	52
Additional paid-in capital	1,314,377	1,242,741
Retained earnings	2,866,837	2,376,331
Accumulated other comprehensive (loss) income	(1,472)	23,430
Total SVBFG stockholders’ equity	4,179,795	3,642,554
Noncontrolling interests	139,620	134,483
Total equity	4,319,415	3,777,037
Total liabilities and total equity	$ 51,214,467	$ 44,683,660

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Available-for-sale Securities, Amortized Cost	$ 11,131,008	$ 12,588,783
Held-to-maturity Securities, Fair Value	$ 12,548,280	$ 8,376,138
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares outstanding	52,835,188	52,254,074

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Interest income:
Loans	$ 1,025,788		$ 834,155		$ 693,147
Investment securities:
Taxable	412,133		346,937		344,646
Non-taxable	5,714		2,234		2,905
Federal funds sold, securities purchased under agreements to resell and other short-term investment securities	21,505		10,070		6,067
Total interest income	1,465,140		1,193,396		1,046,765
Interest expense:
Deposits	8,676		5,611		5,447
Borrowings	36,095		37,262		34,893
Total interest expense	44,771		42,873		40,340
Net interest income	1,420,369		1,150,523		1,006,425
Provision for loan losses	85,939		95,697		97,629
Provision for Loan and Lease Losses	92,304		106,679	[1]	95,683	[1]
Net interest income after provision for loan losses	1,328,065		1,043,844		910,742
Noninterest income:
Gains on investment securities, net	64,603		51,740		89,445
Gains on derivative instruments, net	54,555		37,892		70,963
Foreign exchange fees	115,760		104,183		87,007
Credit card fees	76,543		68,205		56,657
Deposit service charges	58,715		52,524		46,683
Fees and Commissions	43,265		33,395		32,536
Letters of credit and standby letters of credit fees	28,544		25,644		20,889
Asset Management Fees	56,136		32,219		21,610
Other	59,110		50,750		47,004
Noninterest Income	557,231		456,552		472,794
Noninterest expense:
Compensation and benefits	606,402		514,270		473,841
Professional services	121,935		94,982		82,839
Premises and equipment	71,753		65,502		51,927
Business development and travel	41,978		40,130		39,524
Net occupancy	48,397		39,928		34,674
FDIC assessments	35,069		30,285		25,455
Correspondent bank fees	12,976		12,457		13,415
Other	72,145		62,243		58,287
Total noninterest expense	1,010,655		859,797	[1]	779,962	[1]
Income before income tax expense	874,641		640,599		603,574
Income tax expense	355,463	[2]	250,333		228,754
Net income before noncontrolling interests	519,178		390,266		374,820
Net income attributable to noncontrolling interests	(28,672)		(7,581)		(30,916)
Net income available to common stockholders	$ 490,506	[2]	$ 382,685		$ 343,904
Earnings per common share—basic, in dollars per share	$ 9.33	[2]	$ 7.37		$ 6.70
Earnings per common share—diluted, in dollars per share	$ 9.20	[2]	$ 7.31		$ 6.62
[1]	Our consolidated statements of income for the years ended December 31, 2016 and 2015 were modified from prior periods’ presentation to conform to the current period's presentation, which reflects our provision for loan losses and provision for unfunded credit commitments together as our “provision for credit losses”. In prior periods, our provision for unfunded credit commitments were reported separately as a component of noninterest expense.
[2]	Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted, for the year ended December 31, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update ("ASU") 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income before noncontrolling interests	$ 519,178	$ 390,266	$ 374,820
Change in cumulative translation gains (losses):
Foreign currency translation gains (losses)	6,355	(5,245)	2,570
Related tax (expense) benefit	(2,587)	2,050	(957)
Change in unrealized (losses) gains on available-for-sale securities:
Unrealized holding (losses) gains	(47,161)	39,016	(36,702)
Related tax benefit (expense)	19,282	(15,911)	14,730
Reclassification adjustment for losses (gains) included in net income	5,189	(12,195)	(1,201)
Related tax (benefit) expense	(2,098)	4,963	481
Amortization of unrealized gains on securities transferred from available-for-sale to held-to-maturity	(6,475)	(7,786)	(10,412)
Related tax benefit	2,593	3,134	4,191
Other comprehensive (loss) income, net of tax	(24,902)	8,026	(27,300)
Comprehensive income	494,276	398,292	347,520
Comprehensive income attributable to noncontrolling interests	(28,672)	(7,581)	(30,916)
Comprehensive income attributable to SVBFG	$ 465,604	$ 390,711	$ 316,604

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Common stock	Additional Paid-in Capital		Retained Earnings	Accumulated Other Comprehensive Income	Total SVBFG Stockholders’ Equity	Noncontrolling Interests
Balance (in shares) at Dec. 31, 2014			50,924,925
Balance at Dec. 31, 2014		$ 4,051,734	$ 51	$ 1,120,350		$ 1,649,967	$ 42,704	$ 2,813,072	$ 1,238,662
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)			657,876
Common stock issued under employee benefit plans, net of restricted stock cancellations		18,898	$ 1	18,897				18,898
Common stock issued under ESOP (in shares)			27,425
Common stock issued under ESOP		3,512		3,512				3,512
Net income		374,820				343,904		343,904	30,916
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net		16,602		16,602	[1]			16,602
Capital calls and distributions, net		(65,044)							(65,044)
Net change in unrealized gains on available-for-sale securities, net of tax		(22,692)					(22,692)	(22,692)
Amortization of unrealized gains on securities transferred from available-for-sale to held-to-maturity, net of tax		(6,221)					(6,221)	(6,221)
Foreign currency translation adjustments, net of tax		1,613					1,613	1,613
Share-based compensation expense		29,671		29,671				29,671
Other, net		(225)		0		(225)		(225)
Deconsolidation of noncontrolling interest	[2]	(1,069,437)							(1,069,437)
Balance (in shares) at Dec. 31, 2015			51,610,226
Balance at Dec. 31, 2015		3,333,231	$ 52	1,189,032		1,993,646	15,404	3,198,134	135,097
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)			600,683
Common stock issued under employee benefit plans, net of restricted stock cancellations		21,819	$ 0	21,819				21,819
Common stock issued under ESOP (in shares)			43,165
Common stock issued under ESOP		4,328		4,328				4,328
Net income		390,266				382,685		382,685	7,581
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net		(3,640)		(3,640)	[1]			(3,640)
Capital calls and distributions, net		(8,195)							(8,195)
Net change in unrealized gains on available-for-sale securities, net of tax		15,873					15,873	15,873
Amortization of unrealized gains on securities transferred from available-for-sale to held-to-maturity, net of tax		(4,652)					(4,652)	(4,652)
Foreign currency translation adjustments, net of tax		(3,195)					(3,195)	(3,195)
Share-based compensation expense		31,202		31,202				31,202
Balance (in shares) at Dec. 31, 2016			52,254,074
Balance at Dec. 31, 2016		3,777,037	$ 52	1,242,741		2,376,331	23,430	3,642,554	134,483
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)			570,276
Common stock issued under employee benefit plans, net of restricted stock cancellations		24,909	$ 1	24,908				24,909
Common stock issued under ESOP (in shares)			10,838
Common stock issued under ESOP		2,094		2,094				2,094
Net income		519,178				490,506		490,506	28,672
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net		0		0	[1]			0
Capital calls and distributions, net		(23,535)							(23,535)
Net change in unrealized gains on available-for-sale securities, net of tax		(24,788)					(24,788)	(24,788)
Amortization of unrealized gains on securities transferred from available-for-sale to held-to-maturity, net of tax		(3,882)					(3,882)	(3,882)
Foreign currency translation adjustments, net of tax		3,768					3,768	3,768
Share-based compensation expense		44,634		44,634				44,634
Balance (in shares) at Dec. 31, 2017			52,835,188
Balance at Dec. 31, 2017		$ 4,319,415	$ 53	$ 1,314,377		$ 2,866,837	$ (1,472)	$ 4,179,795	$ 139,620
[1]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjI1OTA3ZGEyNTlkYTRjYjA5OThkMzM0ODhkZDAwZDljfFRleHRTZWxlY3Rpb246ODg2NUQxNzNFM0IwOEZDRTUyNzdCNTlBRDlCRDM4QTIM}
[2]	During the second quarter of 2015 we adopted new accounting guidance related to our consolidated variable interest entities (ASU 2015-02). Amounts prior to January 1, 2015 have not been revised for the adoption of this guidance. See Note 2— "Summary of Significant Accounting Policies” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report for additional details.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Cash flows from operating activities:
Net income before noncontrolling interests		$ 519,178	$ 390,266		$ 374,820
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses		92,304	106,679	[1]	95,683	[1]
Gains on investment securities, net		(64,603)	(51,740)		(89,445)
Depreciation and amortization		56,123	46,819		40,008
Amortization of premiums and discounts on available-for-sale securities, net		2,530	6,582		18,271
Amortization of share-based compensation		36,900	35,494		32,239
Amortization of deferred loan fees		(111,738)	(98,150)		(89,384)
Deferred income tax (benefit) expense		25,187	(4,235)		(9,133)
Excess Tax Benefit from Share-based Compensation, Operating Activities	[2]	(18,014)	0		0
Gain (Loss) on Disposition of Business		(5,124)	0		(1,287)
Changes in other assets and liabilities:
Accrued interest receivable and payable, net		(31,372)	(3,663)		(8,397)
Accounts receivable and payable, net		3,481	(4,945)		(24,029)
Income tax payable and receivable, net		46,168	3,672		(9,857)
Accrued compensation		31,689	(15,292)		30,293
Foreign exchange spot contracts, net		(20,891)	3,093		(31,159)
Other, net		15,882	41,684		64,044
Net cash provided by operating activities		580,099	437,977		339,197
Cash flows from investing activities:
Purchases of available-for-sale securities		(2,420,741)	(429,268)		(4,586,680)
Proceeds from sales of available-for-sale securities		580,871	2,892,460		8,054
Proceeds from maturities and pay downs of available-for-sale securities		3,339,574	1,364,398		1,704,918
Purchases of held-to-maturity securities		(5,967,223)	(1,306,010)		(2,888,805)
Proceeds from maturities and paydowns of held-to-maturity securities		1,708,001	1,656,580		1,495,362
Purchases of nonmarketable securities		(43,994)	(48,932)		(39,455)
Proceeds from sales of nonmarketable securities		117,765	96,708		138,453
Net increase in loans		(3,170,099)	(3,157,281)		(2,328,944)
Purchases of premises and equipment		(50,884)	(53,311)		(53,918)
Proceeds from Divestiture of Businesses		3,000			39,284	[3]
Effect of deconsolidation due to adoption of ASU 2015-02		0	0		15,995
Net cash used for investing activities		(5,903,730)	1,015,344		(6,495,736)
Cash flows from financing activities:
Net increase in deposits		5,274,207	(162,908)		4,719,738
Increase (decrease) in short-term borrowings		521,062	(262,232)		767,119
Repayments of Other Long-term Debt		(97,781)	0		0
Proceeds from (Payments of) Capital Calls (Distributions) from Noncontrolling Interest		(23,535)	(8,195)		(23,518)
Proceeds from issuance of common stock, ESPP, and ESOP		27,003	26,147		22,410
Tax benefit from stock exercises	[2]	0	(3,640)		16,602
Proceeds from issuance of 3.50% Senior Notes		0	0		346,431
Net cash provided by financing activities		5,700,956	(410,828)		5,848,782
Net increase (decrease) in cash and cash equivalents		377,325	1,042,493		(307,757)
Cash and cash equivalents at beginning of period		2,545,750	1,503,257		1,811,014	[3]
Cash and cash equivalents at end of period		2,923,075	2,545,750		1,503,257
Cash paid during the period for:
Interest		45,592	42,918		35,280
Income taxes		277,823	240,752		220,484
Noncash items during the period:
Changes in unrealized gains and losses on available-for-sale securities, net of tax		(24,788)	15,873		(22,692)
Distributions Of Stock From Investments		6,807	1,315		64,503	[4]
Equity warrant assets
Adjustments to reconcile net income to net cash provided by operating activities:
Unrealized Gain (Loss) on Derivatives		(11,862)	(9,251)		(54,678)
Derivative
Adjustments to reconcile net income to net cash provided by operating activities:
Unrealized Gain (Loss) on Derivatives		$ 14,261	$ (9,036)		$ 1,208
[1]	Our consolidated statements of income for the years ended December 31, 2016 and 2015 were modified from prior periods’ presentation to conform to the current period's presentation, which reflects our provision for loan losses and provision for unfunded credit commitments together as our “provision for credit losses”. In prior periods, our provision for unfunded credit commitments were reported separately as a component of noninterest expense.
[2]	In 2017 we adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting on a prospective basis with no change to prior period amounts. See Note 2- "Summary of Significant Accounting Policies" of the "Notes to Consolidated Financial Statements" under Part II, Item 8 of this report for additional details.
[3]	Cash and cash equivalents at December 31, 2014 included $15.0 million recognized in assets held-for-sale in conjunction with the SVBIF sale transaction. On April 13, 2015 we received net proceeds of $39.3 million consisting of the sales price of $48.6 million less $9.3 million of cash and cash equivalents held by SVBIF that were sold.
[4]	For the year ended December 31, 2015, includes distributions to our noncontrolling interests of $41.5 million.

Consolidated Statements of Cas8

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Apr. 15, 2015	Dec. 31, 2014
Long Lived Assets Held-for-sale [Line Items]
Noncash or Part Non-Cash, Distributions of Stock from Investments to NCI		$ 41,500
Cash and cash equivalents		1,503,257		$ 1,811,014	[1]
Proceeds from Sales of Assets, Investing Activities	[1]	$ 39,284
Sales price of assets sold			$ 48,600
Cash and cash equivalents included in sale of assets			$ 9,300
Other Assets
Long Lived Assets Held-for-sale [Line Items]
Cash and cash equivalents				$ 15,000
[1]	Cash and cash equivalents at December 31, 2014 included $15.0 million recognized in assets held-for-sale in conjunction with the SVBIF sale transaction. On April 13, 2015 we received net proceeds of $39.3 million consisting of the sales price of $48.6 million less $9.3 million of cash and cash equivalents held by SVBIF that were sold.

Nature of Business

Nature of Business	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business SVB Financial Group is a diversified financial services company, as well as a bank holding company and a financial holding company. SVB Financial was incorporated in the state of Delaware in March 1999. Through our various subsidiaries and divisions, we offer a diverse set of banking and financial products and services to support our clients of all sizes and stages throughout their life cycles. In these notes to our consolidated financial statements, when we refer to “SVB Financial Group,” “SVBFG”, the “Company,” “we,” “our,” “us” or use similar words, we mean SVB Financial Group and all of its subsidiaries collectively, including Silicon Valley Bank (the “Bank”), unless the context requires otherwise. When we refer to “SVB Financial” or the “Parent” we are referring only to the parent company entity, SVB Financial Group (not including subsidiaries). We offer commercial banking products and services through our principal subsidiary, the Bank, which is a California-chartered bank founded in 1983 and a member of the Federal Reserve System. Through its subsidiaries, the Bank also offers asset management, private wealth management and other investment services. We also offer non-banking products and services, such as funds management, private equity/venture capital investment through our other subsidiaries and divisions. We primarily focus on serving corporate clients in the following niches: technology, life science/healthcare, private equity/venture capital and premium wine. Our corporate clients range widely in terms of size and stage of maturity. Additionally, we focus on cultivating strong relationships with firms within the venture capital and private equity community worldwide, many of which are also our clients and may invest in our corporate clients. Headquartered in Santa Clara, California, we operate in centers of innovation in the United States and around the world. For reporting purposes, SVB Financial Group has three operating segments for which we report financial information in this report: Global Commercial Bank, SVB Private Bank, and SVB Capital. Financial information, results of operations and a description of the services provided by our operating segments are set forth in Note 22—“Segment Reporting” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report .

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates and Assumptions The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Estimates may change as new information is obtained. Significant items that are subject to such estimates include measurements of fair value, the valuation of non-marketable and other securities, the valuation of equity warrant assets, the adequacy of the allowance for loan losses and the allowance for unfunded credit commitments and the recognition and measurement of income tax assets and liabilities. The following discussion provides additional background on our significant accounting policies. Principles of Consolidation and Presentation Our consolidated financial statements include the accounts of SVB Financial Group and consolidated entities. We consolidate voting entities in which we have control through voting interests or entities through which we have a controlling financial interest in a variable interest entity ("VIE"). We determine whether we have a controlling financial interest in a VIE by determining if we have (a) the power to direct the activities of the VIE that most significantly impact the entity’s economic performance, (b) the obligation to absorb the expected losses, or (c) the right to receive the expected returns of the entity. Generally, we have significant variable interests if our commitments to a limited partnership investment represent a significant amount of the total commitments to the entity. We also evaluate the impact of related parties on our determination of variable interests in our consolidation conclusions. We consolidate VIEs in which we are the primary beneficiary based on a controlling financial interest. If we are not the primary beneficiary of a VIE, we record our pro-rata interests or our cost basis in the VIE, as appropriate, based on other accounting guidance within GAAP. VIEs are entities where investors lack sufficient equity at risk for the entity to finance its activities without additional subordinated financial support or equity investors and, as a group, lack one of the following characteristics: (a) the power to direct the activities that most significantly impact the entity’s economic performance, (b) the obligation to absorb the expected losses of the entity, or (c) the right to receive the expected returns of the entity. We assess VIEs to determine if we are the primary beneficiary of a VIE. A primary beneficiary is defined as a variable interest holder that has a controlling financial interest. A controlling financial interest requires both: (a) the power to direct the activities that most significantly impact the VIEs economic performance, and (b) the obligation to absorb losses or receive benefits of a VIE that could potentially be significant to a VIE. Under this analysis, we also evaluate kick-out rights and other participating rights, which could provide us a controlling financial interest. The primary beneficiary of a VIE is required to consolidate the VIE. We also evaluate fees paid to managers of our limited partnership investments. We exclude those fee arrangements that are not deemed to be variable interests from the analysis of our interests in our investments in VIEs and the determination of a primary beneficiary, if any. Fee arrangements based on terms that are customary and commensurate with the services provided are deemed not to be variable interests and are, therefore, excluded. All significant intercompany accounts and transactions with consolidated entities have been eliminated. We have not provided financial or other support during the periods presented to any VIE that we were not previously contractually required to provide. Cash and Cash Equivalents Cash and cash equivalents consist of cash on hand, cash balances due from banks, interest-earning deposits, Federal Reserve deposits, federal funds sold, securities purchased under agreements to resell and other short-term investment securities. For the consolidated statements of cash flows, we consider cash equivalents to be investments that are readily convertible to known amounts of cash, so near to their maturity that they present an insignificant risk of change in fair value due to changes in market interest rates, and purchased in conjunction with our cash management activities. Investment Securities Available-for-Sale Securities Our available-for-sale securities portfolio is a fixed income investment portfolio that is managed to earn an appropriate portfolio yield over the long-term while maintaining sufficient liquidity and credit diversification and meeting our asset/liability management objectives. Unrealized gains and losses on available-for-sale securities, net of applicable taxes, are reported in accumulated other comprehensive income, which is a separate component of SVBFG's stockholders' equity, until realized. We analyze available-for-sale securities for other-than-temporary impairment each quarter. Market valuations represent the current fair value of a security at a specified point in time and incorporates the risk of timing of interest due and the return of principal over the contractual life of each security. Gains and losses on securities are realized when there is a sale of the security prior to maturity. A credit downgrade represents an increased level of risk of other-than-temporary impairment, and as a part of our consideration of recording an other-than-temporary impairment we will assess the issuer's ability to service the debt and to repay the principal at contractual maturity. We apply the other-than-temporary impairment standards of ASC 320, Investments-Debt and Equity Securities . For our debt securities, we have the intent and ability to hold these securities until we recover our cost less any credit-related loss. We separate the amount of the other-than-temporary impairment, if any, into the amount that is credit related (credit loss component) and the amount due to all other factors. The credit loss component is recognized in earnings and is the difference between a security's amortized cost basis and the present value of expected future cash flows discounted at the security's effective interest rate. The amount due to all other factors is recognized in other comprehensive income. We consider numerous factors in determining whether a credit loss exists and the period over which the debt security is expected to recover. The following list is not meant to be all inclusive. All of the following factors are considered: • The length of time and the extent to which the fair value has been less than the amortized cost basis (severity and duration); • Adverse conditions specifically related to the security, an industry, or geographic area; for example, changes in the financial condition of the issuer of the security, or in the case of an asset-backed debt security, changes in the financial condition of the underlying loan obligors. Examples of those changes include any of the following: ◦ Changes in technology; ◦ The discontinuance of a segment of the business that may affect the future earnings potential of the issuer or underlying loan obligors of the security; and ◦ Changes in the quality of the credit enhancement. • The historical and implied volatility of the fair value of the security; • The payment structure of the debt security and the likelihood of the issuer being able to make payments that increase in the future; • Failure of the issuer of the security to make scheduled interest or principal payments; • Any changes to the rating of the security by a rating agency; and • Recoveries or additional declines in fair value after the balance sheet date. In accordance with ASC 310-20, Receivables-Nonrefundable Fees and Other Costs , we use estimates of future principal prepayments, provided by third-party market-data vendors, in addition to actual principal prepayment experience to calculate the constant effective yield necessary to apply the effective interest method in the amortization of purchase discounts or premiums on mortgage-backed securities and fixed rate collateralized mortgage obligations (“CMO”). The accretion and amortization of discounts and premiums, respectively, are included in interest income over the contractual terms of the underlying securities replicating the effective interest method. Held-to-Maturity Securities Debt securities purchased in which we have the positive intent and ability to hold to its maturity are classified as held-to-maturity securities and are recorded at amortized cost. Transfers of investment securities into the held-to-maturity category from the available-for-sale category are made at fair value at the date of transfer. The net unrealized gains, net of tax, are retained in other comprehensive income, and the carrying value of the held-to-maturity securities are amortized over the life of the securities in a manner consistent with the amortization of a premium or discount. Our decision to re-designate the securities was based on our ability and intent to hold these securities to maturity. Non-Marketable and Other Securities Non-marketable and other securities include investments in venture capital and private equity funds, SPD Silicon Valley Bank Co., Ltd. (the Bank's joint venture bank in China ("SPD-SVB")), debt funds, private and public portfolio companies and investments in qualified affordable housing projects. A majority of these investments are managed through our SVB Capital funds business in funds of funds and direct venture funds. Our accounting for investments in non-marketable and other securities depends on several factors, including the level of ownership, power to control and the legal structure of the subsidiary making the investment. As further described below, we base our accounting for such securities on: (i) fair value accounting, (ii) equity method accounting, (iii) cost method accounting, and (iv) the proportional amortization method which is used only for qualified affordable housing projects. Fair Value Accounting Our managed funds are investment companies under the AICPA Audit and Accounting Guide for Investment Companies (codified in ASC 946) and accordingly, these funds report their investments at estimated fair value, with unrealized gains and losses resulting from changes in fair value reflected as investment gains or losses in our consolidated statements of income. Our non-marketable and other securities recorded pursuant to fair value accounting consist of our investments through the following funds: • Funds of funds, which make investments in venture capital and private equity funds, • Direct venture funds, which make equity investments in privately held companies. A summary of our ownership interests in the investments held under fair value accounting as of December 31, 2017 is presented in the following table: Limited partnership Company Direct and Indirect Ownership in Limited Partnership Managed funds of funds Strategic Investors Fund, LP 12.6 % Capital Preferred Return Fund, LP 20.0 Growth Partners, LP 33.0 Managed direct venture funds CP I, LP 10.7 The general partner interests of these funds are controlled, and in some cases, owned by SVB Financial. The limited partners of these funds do not have substantive participating or kick-out rights. Therefore, these funds are consolidated and any gains or losses resulting from changes in the estimated fair value of the investments are recorded as investment gains or losses in our consolidated net income. Under fair value accounting, investments are carried at their estimated fair value based on financial information obtained as the general partner of the fund or obtained from the funds' respective general partner. For direct private company investments, valuations are based upon consideration of a range of factors including, but not limited to, the price at which the investment was acquired, the term and nature of the investment, local market conditions, values for comparable securities, current and projected operating performance, exit strategies and financing transactions subsequent to the acquisition of the investment. For direct equity investments in public companies, valuations are based on quoted market prices less a discount if the securities are subject to certain sales restrictions. Sales restriction discounts generally range from ten percent to twenty percent depending on the duration of the sale restrictions which typically range from three to six months. The valuation of non-marketable securities in shares of private company capital stock and the valuation of other securities in shares of public company stock with certain sales restrictions is subject to significant judgment. The inherent uncertainty in the process of valuing securities for which a ready market does not exist may cause our estimated values of these securities to differ significantly from the values that would have been derived had a ready market for the securities existed, and those differences could be material. For our fund investments, we utilize the net asset value as obtained from the general partners of the fund investments as the funds do not have a readily determinable fair value. The general partners of our fund investments prepare their financial statements using guidance consistent with fair value accounting. We account for differences between our measurement date and the date of the fund investment's net asset value by using the most recent available financial information from the investee general partner, for example September 30 th , for our December 31 st consolidated financial statements. We adjust the value of our investments for any contributions paid, distributions received from the investment, and known significant fund transactions or market events about which we are aware through information provided by the fund managers or from publicly available transaction data during the reporting period. Gains or losses resulting from changes in the estimated fair value of the investments and from distributions received are recorded as gains on investment securities, net, a component of noninterest income. The portion of any investment gains or losses attributable to the limited partners is reflected as net income attributable to noncontrolling interests and adjusts our net income to reflect its percentage ownership. Equity Method Our equity method non-marketable securities consist of investments in venture capital and private equity funds, privately-held companies, debt funds, and joint ventures. Our equity method non-marketable securities and related accounting policies are described as follows: • Equity securities, such as preferred or common stock in privately-held companies in which we hold a voting interest of at least 20 percent , or in which we have the ability to exercise significant influence over the investees' operating and financial policies through board involvement or other influence, are accounted for under the equity method. • Investments in limited partnerships in which we hold voting interests of more than 5 percent , or in which we have the ability to exercise significant influence over the partnerships' operating and financial policies, are accounted for using the equity method. • Our China Joint Venture partnership, for which we have 50 percent ownership, is accounted for under the equity method. We recognize our proportionate share of the results of operations of these equity method investees in our results of operations, based on the most current financial information available from the investee. We review our investments accounted for under the equity method at least quarterly for possible other-than-temporary impairment. Our review typically includes an analysis of facts and circumstances for each investment, the expectations of the investment's future cash flows and capital needs, variability of its business and the company's exit strategy. For our fund investments, we utilize the net asset value per share as provided by the general partners of the fund investments. We account for differences between our measurement date and the date of the fund investment's net asset value by using the most recent available financial information from the investee general partner, for example September 30 th , for our December 31 st consolidated financial statements. We adjust the value of our investments for any contributions paid, distributions received from the investment, and known significant fund transactions or market events about which we are aware through information provided by the fund managers or from publicly available transaction data during the reporting period. We reduce our investment value when we consider declines in value to be other-than-temporary and recognize the estimated loss as a loss on investment securities, a component of noninterest income. Cost Method Our cost method non-marketable securities and related accounting policies are described as follows: • Equity securities, such as preferred or common stock in privately-held companies in which we hold an ownership interest in which we do not have the ability to exercise significant influence over the investees' operating and financial policies, are accounted for under the cost method. • Investments in limited partnerships in which we hold voting interests of less than 5 percent and in which we do not have the ability to exercise significant influence over the partnerships' operating and financial policies, are accounted for under the cost method. These non-marketable securities include investments in venture capital and private equity funds. We record these investments at cost and recognize distributions or returns received from net accumulated earnings of the investee since the date of acquisition as income. Our share of net accumulated earnings of the investee after the date of investment are recognized in consolidated net income only to the extent distributed by the investee. Distributions or returns received in excess of accumulated earnings are considered a return of investment and are recorded as reductions in the cost basis of the investment. We review our investments accounted for under the cost method at least quarterly for possible other-than-temporary impairment. Our review typically includes an analysis of facts and circumstances of each investment, the expectations of the investment's future cash flows and capital needs, variability of its business and the company's exit strategy. To help determine impairment, if any, for our fund investments, we utilize the net asset value per share as provided by the general partners of the fund investments. We reduce our investment value when we consider declines in value to be other-than-temporary and recognize the estimated loss as a loss on investment securities, a component of noninterest income. Gains or losses on cost method investment securities that result from a portfolio company being acquired by a publicly traded company are determined using the fair value of the consideration received when the acquisition occurs. The resulting gains or losses are recognized in consolidated net income in the period of acquisition. Proportional Amortization Method In order to fulfill our responsibilities under the Community Reinvestment Act, we invest as a limited partner in low income housing partnerships that operate qualified affordable housing projects and generate tax benefits, including federal low income housing tax credits, for investors. The partnerships are deemed to be VIEs because they do not have sufficient equity investment at risk and are structured with non-substantive voting rights. We are not the primary beneficiary of the VIEs and do not consolidate them. Our investments in low income housing partnerships are recorded in non-marketable and other securities within our investment securities portfolio on the consolidated balance sheet. As a practical expedient, we amortize the investment in proportion to the allocated tax benefits under the proportional amortization method of accounting and present such benefits net of investment amortization in income tax expense. Loans Loans are reported at the principal amount outstanding, net of unearned loan fees. Unearned loan fees reflect unamortized deferred loan origination and commitment fees net of unamortized deferred loan origination costs. In addition to cash loan fees, we often obtain equity warrant assets that give us an option to purchase a position in a client company's stock in consideration for providing credit facilities. The grant date fair values of these equity warrant assets are deemed to be loan fees and are deferred as unearned income and recognized as an adjustment of loan yield through loan interest income. The net amount of unearned loan fees is amortized into loan interest income over the contractual terms of the underlying loans and commitments using the constant effective yield method, adjusted for actual loan prepayment experience, or the straight-line method, as applicable. Allowance for Loan Losses The allowance for loan losses considers credit risk and is established through a provision for loan losses charged to expense. Our allowance for loan losses is established for estimated loan losses that are probable and incurred but not yet realized. Our evaluation process is designed to determine that the allowance for loan losses is appropriate at the balance sheet date. The process of estimating loan losses is inherently imprecise. We maintain a systematic process for the evaluation of individual loans and pools of loans for inherent risk of loan losses. At the time of approval, each loan in our portfolio is assigned a Credit Risk Rating and industry niche. Credit Risk Ratings are assigned on a scale of 1 to 10, with 1 representing loans with a low risk of nonpayment, 9 representing loans with the highest risk of nonpayment, and 10 representing loans which have been charged-off. The credit risk ratings for each loan are monitored and updated on an ongoing basis. This Credit Risk Rating process includes, but is not limited to, consideration of such factors as payment status, the financial condition and operating performance of the borrower, borrower compliance with loan covenants, underlying collateral values and performance trends, the degree of access to additional capital, the presence of credit enhancements such as third party guarantees (where applicable), the degree to which the borrower is sensitive to external factors, the depth and experience of the borrower's management team, potential loan concentrations, and general economic conditions. Our policies require a committee of senior management to review, at least quarterly, credit relationships with a credit risk rating of 5 through 9 that exceed specific dollar values. Our review process evaluates the appropriateness of the credit risk rating and allocation of the allowance for loan losses, as well as other account management functions. The allowance for loan losses is determined based on a qualitative analysis and a formula allocation for similarly risk-rated loans by portfolio segment and individually for impaired loans. The formula allocation provides the average loan loss experience for each portfolio segment, which considers our quarterly historical loss experience since the year 2000, both by risk-rating category and client industry sector. The resulting loan loss factors for each risk-rating category and client industry sector are ultimately applied to the respective period-end client loan balances for each corresponding risk-rating category by client industry sector to provide an estimation of the allowance for loan losses. The probable loan loss experience for any one year period of time is reasonably expected to be greater or less than the average as determined by the loss factors. As such, management applies a qualitative allocation to the results of the aforementioned model to ascertain the total allowance for loan losses. This qualitative allocation is based on management's assessment of the risks that may lead to a loan loss experience different from our historical loan loss experience. Based on management's prediction or estimate of changing risks in the lending environment, the qualitative allocation may vary significantly from period to period and includes, but is not limited to, consideration of the following factors: • Changes in lending policies and procedures, including underwriting standards and collections, and charge-off and recovery practices; • Changes in national and local economic business conditions, including the market and economic condition of our clients' industry sectors; • Changes in the nature of our loan portfolio; • Changes in experience, ability, and depth of lending management and staff; • Changes in the trend of the volume and severity of past due and classified loans; • Changes in the trend of the volume of nonaccrual loans, troubled debt restructurings, and other loan modifications; • Reserve floor for portfolio segments that would not draw a minimum reserve based on the lack of historical loan loss experience; • Reserve for large funded loan exposure; • Reserve for performing impaired loan exposure; and • Other factors as determined by management from time to time. While the evaluation process of our allowance for loan losses uses historical and other objective information, the classification of loans and the establishment of the allowance for loan losses rely, to a great extent, on the judgment and experience of our management. Allowance for Unfunded Credit Commitments We record a liability for probable and estimable incurred losses associated with our unfunded credit commitments being funded and subsequently being charged off. Each quarter, every unfunded client credit commitment is allocated to a credit risk-rating in accordance with each client's credit risk rating and portfolio segment. We use the segment specific historical loan loss factors described under our allowance for loan losses to calculate the loan loss experience if unfunded credit commitments are funded. Separately, we use historical trends to calculate a probability of an unfunded credit commitment being funded. We apply the loan funding probability factor to risk-factor adjusted unfunded credit commitments by credit risk-rating and portfolio segment to derive the allowance for unfunded credit commitments, similar to funded loans. The allowance for unfunded credit commitments also includes certain qualitative allocations as deemed appropriate by management. We include the allowance for unfunded credit commitments in other liabilities and the related provision in our provision for credit losses. Uncollectible Loans and Write-offs Our charge-off policy applies to all loans, regardless of portfolio segment. Commercial loans are considered for a full or partial charge-off in the event that principal or interest is over 180 days past due and the loan lacks sufficient collateral and it is not in the process of collection, provided that a loss event has been defined and the charge-off is consistent with GAAP. Consumer loans are considered for a full or partial charge-off in the event that principal or interest is over 120 days past due and the loan lacks sufficient collateral and it is not in the process of collection, provided that a loss event has been defined and the charge-off is consistent with GAAP. We also consider writing off loans in the event of any of the following circumstances: 1) the loan, or a portion of the loan is deemed uncollectible due to: a) the borrower's inability to make recurring payments, b) material changes in the borrower's financial condition, or c) the expected sale of all or a portion of the borrower's business is insufficient to repay the loan in full, or 2) the loan has been identified for charge-off by regulatory authorities. Troubled Debt Restructurings A TDR arises from the modification of a loan where we have granted a concession to the borrower related to the borrower's financial difficulties that we would not have otherwise considered for economic or legal reasons. These concessions may include: (1) deferral of payment for more than an insignificant period of time that does not include sufficient offsetting borrower concessions; (2) interest rate reductions; (3) extension of the maturity date outside of ordinary course extension; (4) principal forgiveness; and/or (5) reduction of accrued interest. We use the factors in ASC 310-40, Receivables, Troubled Debt Restructurings by Creditors, in analyzing when a borrower is experiencing financial difficulty, and when we have granted a concession, both of which must be present for a restructuring to meet the criteria of a TDR. If we determine that a TDR exists, we measure impairment based on the present value of expected future cash flows discounted at the loan's effective interest rate, except that as a practical expedient, we may also measure impairment based on a loan's observable market price, or the fair value of the collateral less selling costs if the loan is a collateral-dependent loan. Impaired Loans A loan is considered impaired when, based upon currently known information, it is deemed probable that we will be unable to collect all amounts due according to the contractual terms of the agreement. On a quarterly basis, we review our loan portfolio for impairment. Within each class of loans, we review individual loans for impairment based on credit risk ratings. Loans risk-rated 5 through 7 are performing loans; however, we consider them as demonstrating higher risk, which requires more frequent review of the individual exposures; these translate to an internal rating of "Performing (Criticized)" and could be classified as a performing impaired loan. For each loan identified as impaired, we measure the impairment based upon the present value of expected future cash flows discounted at the loan's effective interest rate. In limited circumstances, we may measure impairment based on the loan's observable market price or the fair value of the collateral less selling costs if the loan is collateral dependent. Impaired collateral dependent loans will have independent appraisals completed and accepted at least annually. The fair value of the collateral will be determined by the most recent appraisal, as adjusted to reflect a reasonable marketing period for the sale of the asset(s) and an estimate of reasonable selling expenses. If it is determined that the value of an impaired loan is less than the recorded investment in the loan, net of previous charge-offs and payments collected, we recognize impairment through the allowance for loan losses as determined by our analysis. Nonaccrual Loans Loans are placed on nonaccrual status when they become 90 days past due as to principal or interest payments (unless the principal and interest are well secured and in the process of collection); or when we have determined, based upon currently known information, that the timely collection of principal or interest is not probable. When a loan is placed on nonaccrual status, the accrued interest and fees are reversed against interest income and the loan is accounted for using the cost recovery method thereafter until qualifying for return to accrual status. Historically, loans that have been placed on nonaccrual status have remained as nonaccrual loans until the loan is either charged-off, or the principal balances have been paid off. For a loan to be returned to accrual status, all delinquent principal and interest must become current in accordance with the terms of the loan agreement and future collection of remaining principal and interest must be deemed probable. We apply a cost recovery method in which all cash received is applied to the loan principal until it has been collected. Under this approach, interest income is recognized after total cash flows received exceed the recorded investment at the date of initial nonaccrual. All of our nonaccrual loans have credit risk ratings of 8 or 9 and are classified under the nonperforming impaired category. Premises and Equipment Premises and equipment are reported at cost less accumulated depreciation and amortization. Depreciation and amortization are computed using the straight-line method over t

Stockholders' Equity and EPS

Stockholders' Equity and EPS	12 Months Ended
	Dec. 31, 2017
Equity and Earnings Per Share [Abstract]
Stockholders' Equity and EPS	Stockholders' Equity and EPS Accumulated Other Comprehensive (Loss) Income The following table summarizes the items reclassified out of accumulated other comprehensive income into the Consolidated Statements of Income for 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) Income Statement Location 2017 2016 2015 Reclassification adjustment for losses (gains) included in net income Gains on investment securities, net $ 5,189 $ (12,195 ) $ (1,201 ) Related tax (benefit) expense Income tax expense (2,098 ) 4,963 481 Total reclassification adjustment for losses (gains) included in net income, net of tax $ 3,091 $ (7,232 ) $ (720 ) EPS Basic EPS is the amount of earnings available to each share of common stock outstanding during the reporting period. Diluted EPS is the amount of earnings available to each share of common stock outstanding during the reporting period adjusted to include the effect of potentially dilutive common shares. Potentially dilutive common shares include incremental shares issuable for stock option and restricted stock unit awards outstanding under our 2006 Equity Incentive Plan and our ESPP. Potentially dilutive common shares are excluded from the computation of dilutive EPS in periods in which the effect would be antidilutive. The following is a reconciliation of basic EPS to diluted EPS for 2017 , 2016 and 2015 : Year ended December 31, (Dollars and shares in thousands, except per share amounts) 2017 2016 2015 Numerator: Net income available to common stockholders $ 490,506 $ 382,685 $ 343,904 Denominator: Weighted average common shares outstanding—basic 52,588 51,915 51,318 Weighted average effect of dilutive securities: Stock options and ESPP 385 254 387 Restricted stock units 333 180 211 Weighted average common shares outstanding—diluted 53,306 52,349 51,916 Earnings per common share: Basic $ 9.33 $ 7.37 $ 6.70 Diluted 9.20 7.31 6.62 The following table summarizes the weighted average common shares excluded from the diluted EPS calculation due to the antidilutive effect for 2017 , 2016 and 2015 : Year ended December 31, (Shares in thousands) 2017 2016 2015 Stock options 73 272 185 Restricted stock units 1 1 — Total 74 273 185

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation Share-based compensation expense was recorded net of estimated forfeitures for 2017 , 2016 and 2015 , such that expense was recorded only for those share-based awards that are expected to vest. In 2017 , 2016 and 2015 , we recorded share-based compensation and related benefits as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Share-based compensation expense $ 36,900 $ 35,494 $ 32,239 Income tax benefit related to share-based compensation expense (12,845 ) (12,505 ) (11,395 ) Capitalized compensation costs 1,071 5,580 2,226 Equity Incentive Plan Our 2006 Equity Incentive Plan (the “2006 Incentive Plan”) was adopted in May 2006, and is amended from time to time. The 2006 Incentive Plan provides for the grant of various types of incentive awards, of which the following have been granted: (i) stock options; (ii) restricted stock awards; (iii) restricted stock units (subject to either time-and/or performance-based vesting); and (iv) other cash or stock settled equity awards. Eligible participants in the 2006 Incentive Plan include directors, employees and consultants. Subject to the provisions of Section 16 of the 2006 Incentive Plan, the maximum aggregate number of shares that may be awarded and sold thereunder is 9,528,505 . Restricted stock awards/units are counted against the available-for-issuance limits of the 2006 Incentive Plan as two shares for every one share awarded. Further, if shares acquired under any such award are forfeited, repurchased by SVB Financial, used to satisfy the tax withholding obligations related to an award, or otherwise canceled and would otherwise return to the 2006 Incentive Plan, two times the number of such shares will return to the 2006 Incentive Plan and will again become available for issuance. Under the terms of the 2006 Incentive Plan and subject to certain exceptions: (i) restricted stock awards/units are subject to a minimum of at least three years of annual vesting, and (ii) performance-based restricted stock awards/units and stock options are subject to a minimum of at least one year of vesting. Generally in practice, restricted stock awards/units vest annually over four years and require continued employment or other service through the vesting period. Performance-based restricted stock awards/units granted to executives generally vest upon meeting certain performance-based objectives over a three year period and, typically the passage of time, and require continued employment or other service through the vesting period. Stock options typically vest annually over four years, from the grant date based on continued employment or other service, and expire no later than seven years after the grant date. Employee Stock Purchase Plan We maintain the 1999 ESPP under which participating employees may annually contribute up to 10 percent of their gross compensation (not to exceed $25,000 ) to purchase shares of our common stock at 85 percent of its fair market value at either the beginning or end of each six-month offering period, whichever price is less. To be eligible to participate in the ESPP, an employee must, among other requirements, be employed by the Company on both the date of offering and date of purchase, and be employed customarily for at least 20 hours per week and at least five months per calendar year. We issued 122,882 shares and received $18.2 million in cash under the ESPP in 2017 . At December 31, 2017 , a total of 1,614,399 shares of our common stock were still available for future issuance under the ESPP. Unrecognized Compensation Expense As of December 31, 2017 , unrecognized share-based compensation expense was as follows: (Dollars in thousands) Unrecognized Expense Weighted Average Expected Recognition Period - in Years Stock options $ 9,630 2.59 Restricted stock units 50,530 2.59 Total unrecognized share-based compensation expense $ 60,160 Valuation Assumptions The fair values of share-based awards for employee stock options and employee stock purchases made under our ESPP were estimated using the Black-Scholes option pricing model. The fair values of restricted stock units were based on our closing stock price on the date of grant. The following weighted average assumptions and fair values were used for our employee stock options and restricted stock units: Equity Incentive Plan Awards 2017 2016 2015 Weighted average expected term of options - in years 4.9 4.8 4.7 Weighted average expected volatility of the Company's underlying common stock 33.7 % 31.7 % 31.3 % Risk-free interest rate 1.81 1.32 1.49 Expected dividend yield — — — Weighted average grant date fair value - stock options $ 57.81 $ 31.17 $ 37.86 Weighted average grant date fair value - restricted stock units 181.23 100.35 129.23 The following weighted average assumptions and fair values were used for our ESPP: ESPP 2017 2016 2015 Expected term in years 0.5 0.5 0.5 Weighted average expected volatility of the Company's underlying common stock 31.2 % 41.8 % 25.9 % Risk-free interest rate 0.80 0.45 0.12 Expected dividend yield — — — Weighted average grant date fair value $ 41.70 $ 29.16 $ 29.27 The expected term is based on the implied term of the stock options using factors based on historical exercise behavior. The expected volatilities are based on a blended rate consisting of our historic volatility and our expected volatility over a five -year term which is an indicator of expected volatility and future stock price trends. For 2017 , 2016 and 2015 , expected volatilities for the ESPP were equal to the historical volatility for the previous six-month periods. The expected risk-free interest rates were based on the yields of U.S. Treasury securities, as reported by the Federal Reserve Bank of New York, with maturities equal to the expected terms of the employee stock options. Share-Based Payment Award Activity The table below provides stock option information related to the 2006 Equity Incentive Plan for the year ended December 31, 2017 : Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life - in Years Aggregate Intrinsic Value of In-The-Money Options Outstanding at December 31, 2016 1,010,557 $ 87.24 Granted 116,995 179.39 Exercised (302,744 ) 71.65 Forfeited (16,759 ) 122.97 Outstanding at December 31, 2017 808,049 105.68 3.69 $ 103,506,420 Vested and expected to vest at December 31, 2017 787,182 104.69 3.64 101,607,636 Exercisable at December 31, 2017 464,685 84.86 2.57 69,197,233 The aggregate intrinsic value of outstanding options shown in the table above represents the pre-tax intrinsic value based on our closing stock price of $233.77 as of December 31, 2017 . The following table summarizes information regarding stock options outstanding and exercisable as of December 31, 2017 : Outstanding Options Exercisable Options Range of Exercise Prices Shares Weighted Average Remaining Contractual Life - in Years Weighted Average Exercise Price Shares Weighted Average Exercise Price $42.79 - 63.62 52,630 0.52 $ 59.22 52,630 $ 59.22 63.63 - 67.77 84,961 1.33 64.37 84,961 64.37 67.78 - 79.77 141,026 2.33 71.11 141,026 71.11 79.78 - 105.14 11,686 3.67 98.17 7,336 96.09 105.15 - 105.84 154,345 5.33 105.18 31,958 105.18 105.85 - 108.59 148,456 3.32 107.96 101,824 107.95 108.60 - 149.65 102,306 4.27 128.65 44,950 128.13 149.66 - 180.62 108,266 6.34 178.15 — — 180.63 - 217.69 4,373 6.80 210.42 — — Total 808,049 3.69 105.68 464,685 84.86 We expect to satisfy the exercise of stock options by issuing shares under the 2006 Incentive Plan. All future awards of stock options and restricted stock units will be issued from the 2006 Incentive Plan. At December 31, 2017 , 2,091,064 shares were available for future issuance. The table below provides information for restricted stock units under the 2006 Equity Incentive Plan for the year ended December 31, 2017 : Shares Weighted Average Grant Date Fair Value Nonvested at December 31, 2016 670,969 $ 106.64 Granted 247,591 181.23 Vested (228,198 ) 102.47 Forfeited (52,695 ) 121.52 Nonvested at December 31, 2017 637,667 135.86 The following table summarizes information regarding stock option and restricted stock unit activity during 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Total intrinsic value of stock options exercised $ 36,173 $ 18,186 $ 27,430 Total grant date fair value of stock options vested 6,094 7,364 21,052 Total intrinsic value of restricted stock vested 40,925 22,966 34,009 Total grant date fair value of restricted stock vested 23,383 19,454 19,428

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2017
Investments In Variable Interest Entities [Abstract]
Variable Interest Entities	Variable Interest Entities Our involvement with VIEs includes our investments in venture capital and private equity funds, debt funds, private and public portfolio companies and our investments in qualified affordable housing projects. The following table presents the carrying amounts and classification of significant variable interests in consolidated and unconsolidated VIEs as of December 31, 2017 and December 31, 2016 : (Dollars in thousands) Consolidated VIEs Unconsolidated VIEs Maximum Exposure to Loss in Unconsolidated VIEs December 31, 2017: Assets: Cash and cash equivalents $ 6,674 $ — $ — Non-marketable and other securities (1) 190,562 346,097 346,097 Accrued interest receivable and other assets 365 — — Total assets $ 197,601 $ 346,097 $ 346,097 Liabilities: Other liabilities (1) 990 100,891 — Total liabilities $ 990 $ 100,891 $ — December 31, 2016: Assets: Cash and cash equivalents $ 11,469 $ — $ — Non-marketable and other securities (1) 196,140 314,810 314,810 Accrued interest receivable and other assets 294 — — Total assets $ 207,903 $ 314,810 $ 314,810 Liabilities: Other liabilities (1) 517 58,095 — Total liabilities $ 517 $ 58,095 $ — (1) Included in our unconsolidated non-marketable and other securities portfolio at December 31, 2017 and December 31, 2016 are investments in qualified affordable housing projects of $174.2 million and $112.4 million , respectively, and related other liabilities consisting of unfunded credit commitments of $100.9 million and $58.1 million , respectively. Non-marketable and other securities Our non-marketable and other securities portfolio primarily represents investments in venture capital and private equity funds, SPD Silicon Valley Bank Co., Ltd. (the Bank's joint venture in China ("SPD-SVB")), debt funds, private and public portfolio companies and investments in qualified affordable housing projects. A majority of these investments are through third party funds held by SVB Financial in which we do not have controlling or significant variable interests. These investments represent our unconsolidated VIEs in the table above. Our non-marketable and other securities portfolio also includes investments from SVB Capital. SVB Capital is the funds management business of SVB Financial Group, which focuses primarily on venture capital investments. The SVB Capital family of funds is comprised of direct venture funds that invest in companies and funds of funds that invest in other venture capital funds. We have a controlling and significant variable interest in four of these SVB Capital funds and consolidate these funds for financial reporting purposes. All investments are generally non-redeemable and distributions are expected to be received through the liquidation of the underlying investments throughout the life of the investment fund. Investments may only be sold or transferred subject to the notice and approval provisions of the underlying investment agreement. Subject to applicable regulatory requirements, including the Volcker Rule, we also make commitments to invest in venture capital and private equity funds. For additional details, see Note 19—“Off-Balance Sheet Arrangements, Guarantees and Other Commitments” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report . The Bank also has variable interests in qualified affordable housing projects tax credit funds, in connection with fulfilling its responsibilities under the Community Reinvestment Act ("CRA"), that are designed to generate a return primarily through the realization of federal tax credits. These investments are typically limited partnerships in which the general partner, other than the Bank, holds the power over significant activities of the VIE; therefore, these investments are not consolidated. For additional information on our investments in qualified affordable housing projects see Note 8—“Investment Securities" of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report . As of December 31, 2017 , our exposure to loss with respect to the consolidated VIEs is limited to our net assets of $196.6 million and our exposure to loss for our unconsolidated VIEs is equal to our investment in these assets of $346.1 million .

Reserves on Deposit with the Fe

Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock	12 Months Ended
	Dec. 31, 2017
Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock [Abstract]
Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock	Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock The Bank is required to maintain reserves against customer deposits by keeping balances with the Federal Reserve. The cash balances at the Federal Reserve are classified as cash and cash equivalents. Additionally, as a member of the FHLB and FRB, we are required to hold shares of FHLB and FRB stock under the Bank's borrowing agreement. FHLB and FRB stock are recorded at cost as a component of other assets, and any cash dividends received are recorded as a component of other noninterest income. The tables below provide information on the required reserve balances at the Federal Reserve, as well as shares held at the FHLB and FRB for the years ended and as of December 31, 2017 and 2016 : Year ended December 31, (Dollars in thousands) 2017 2016 Average required reserve balances at FRB San Francisco $ 397,235 $ 370,002 December 31, (Dollars in thousands) 2017 2016 FHLB stock holdings $ 18,900 $ 17,250 FRB stock holdings 41,120 40,342

Cash and Cash Equivalents

Cash and Cash Equivalents	12 Months Ended
	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	Cash and Cash Equivalents The following table details our cash and cash equivalents at December 31, 2017 and December 31, 2016 : (Dollars in thousands) December 31, 2017 December 31, 2016 Cash and due from banks (1) $ 2,672,290 $ 2,476,588 Securities purchased under agreements to resell (2) 247,876 64,028 Other short-term investment securities 2,909 5,134 Total cash and cash equivalents $ 2,923,075 $ 2,545,750 (1) At December 31, 2017 and 2016 , $0.6 billion and $1.1 billion , respectively, of our cash and due from banks was deposited at the FRB and was earning interest at the Federal Funds target rate, and interest-earning deposits in other financial institutions were $1.1 billion and $0.7 billion , respectively. (2) At December 31, 2017 and 2016 , securities purchased under agreements to resell were collateralized by U.S. Treasury securities and U.S. agency securities with aggregate fair values of $253 million and $66 million , respectively. None of these securities were sold or repledged as of December 31, 2017 and 2016 . Additional information regarding our securities purchased under agreements to resell for 2017 and 2016 are as follows: Year Ended December 31, (Dollars in thousands) 2017 2016 Average securities purchased under agreements to resell $ 94,094 $ 90,362 Maximum amount outstanding at any month-end during the year 377,073 316,059

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities Our investment securities portfolio consists of: (i) an available-for-sale securities portfolio and a held-to-maturity securities portfolio, both of which represent interest-earning investment securities; and (ii) a non-marketable and other securities portfolio, which primarily represents investments managed as part of our funds management business. Available-for-Sale Securities The major components of our AFS investment securities portfolio at December 31, 2017 and 2016 are as follows: December 31, 2017 (Dollars in thousands) Amortized Unrealized Unrealized Carrying Available-for-sale securities, at fair value: U.S. Treasury securities $ 6,865,068 $ 1,113 $ (25,679 ) $ 6,840,502 U.S. agency debentures 1,569,195 3,569 (5,636 ) 1,567,128 Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations—fixed rate 2,292,311 258 (25,534 ) 2,267,035 Agency-issued collateralized mortgage obligations—variable rate 372,481 1,375 (126 ) 373,730 Equity securities 31,953 40,525 (209 ) 72,269 Total available-for-sale securities $ 11,131,008 $ 46,840 $ (57,184 ) $ 11,120,664 December 31, 2016 (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Carrying Value Available-for-sale securities, at fair value: U.S. Treasury securities $ 8,880,358 $ 30,323 $ (1,190 ) $ 8,909,491 U.S. agency debentures 2,065,535 14,443 (1,603 ) 2,078,375 Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations—fixed rate 1,163,017 3,046 (13,398 ) 1,152,665 Agency-issued collateralized mortgage obligations—variable rate 474,238 685 (640 ) 474,283 Equity securities 5,635 748 (786 ) 5,597 Total available-for-sale securities $ 12,588,783 $ 49,245 $ (17,617 ) $ 12,620,411 The following tables summarize our unrealized losses on our AFS securities portfolio into categories of less than 12 months, or 12 months or longer as of December 31, 2017 and 2016 : December 31, 2017 Less than 12 months 12 months or longer Total (Dollars in thousands) Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Available-for-sale securities: U.S. Treasury securities $ 5,968,914 $ (23,397 ) $ 323,966 $ (2,282 ) $ 6,292,880 $ (25,679 ) U.S. agency debentures 736,541 (2,289 ) 336,196 (3,347 ) 1,072,737 (5,636 ) Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations—fixed rate 2,193,277 (25,534 ) — — 2,193,277 (25,534 ) Agency-issued collateralized mortgage obligations—variable rate 13,843 (3 ) 53,186 (123 ) 67,029 (126 ) Equity securities 624 (209 ) — — 624 (209 ) Total temporarily impaired securities (1) $ 8,913,199 $ (51,432 ) $ 713,348 $ (5,752 ) $ 9,626,547 $ (57,184 ) (1) As of December 31, 2017 , we identified a total of 268 investments that were in unrealized loss positions, of which 46 investments totaling $713.3 million with unrealized losses of $5.8 million have been in an impaired position for a period of time greater than 12 months. As of December 31, 2017 , we do not intend to sell any of our impaired securities prior to recovery of our adjusted cost basis, and it is more likely than not that we will not be required to sell any of our securities prior to recovery of our adjusted cost basis. Based on our analysis as of December 31, 2017 , we deem all impairments to be temporary, and therefore changes in value for our temporarily impaired securities as of the same date are included in other comprehensive income. Market valuations and impairment analyses on assets in the AFS securities portfolio are reviewed and monitored on a quarterly basis. December 31, 2016 Less than 12 months 12 months or longer Total (Dollars in thousands) Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Available-for-sale securities: U.S. Treasury securities $ 879,255 $ (1,190 ) $ — $ — $ 879,255 $ (1,190 ) U.S. agency debentures 513,198 (1,603 ) — — 513,198 (1,603 ) Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations—fixed rate 635,566 (6,704 ) 227,480 (6,694 ) 863,046 (13,398 ) Agency-issued collateralized mortgage obligations—variable rate 258,325 (613 ) 6,068 (27 ) 264,393 (640 ) Equity securities 3,693 (786 ) — — 3,693 (786 ) Total temporarily impaired securities (1) $ 2,290,037 $ (10,896 ) $ 233,548 $ (6,721 ) $ 2,523,585 $ (17,617 ) (1) As of December 31, 2016 , we identified a total of 174 investments that were in unrealized loss positions, of which 20 investments totaling $233.5 million with unrealized losses of $6.7 million have been in an impaired position for a period of time greater than 12 months. The following table summarizes the fixed income securities, carried at fair value, classified as AFS as of December 31, 2017 by the remaining contractual principal maturities. For U.S. Treasury securities and U.S. agency debentures, the expected maturity is the actual contractual maturity of the notes. Expected maturities for mortgage-backed securities may differ significantly from their contractual maturities because mortgage borrowers have the right to prepay outstanding loan obligations with or without penalties. Mortgage-backed securities classified as AFS typically have original contractual maturities from 10 to 30 years whereas expected average lives of these securities tend to be significantly shorter and vary based upon structure and prepayments in lower rate environments. December 31, 2017 (Dollars in thousands) Total One Year After One After Five After U.S. Treasury securities $ 6,840,502 $ 1,967,480 $ 4,873,022 $ — $ — U.S. agency debentures 1,567,128 481,280 1,085,848 — — Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations - fixed rate 2,267,035 — — 88,425 2,178,610 Agency-issued collateralized mortgage obligations - variable rate 373,730 — — — 373,730 Total $ 11,048,395 $ 2,448,760 $ 5,958,870 $ 88,425 $ 2,552,340 Held-to-Maturity Securities The components of our HTM investment securities portfolio at December 31, 2017 and 2016 are as follows: December 31, 2017 (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Held-to-maturity securities, at cost: U.S. agency debentures (1) $ 659,979 $ 3,167 $ (1,601 ) $ 661,545 Residential mortgage-backed securities: Agency-issued mortgage-backed securities 6,304,969 4,854 (43,528 ) 6,266,295 Agency-issued collateralized mortgage obligations—fixed rate 2,829,979 23 (54,372 ) 2,775,630 Agency-issued collateralized mortgage obligations—variable rate 255,782 733 (34 ) 256,481 Agency-issued commercial mortgage-backed securities 1,868,985 694 (25,563 ) 1,844,116 Municipal bonds and notes 743,761 3,452 (3,000 ) 744,213 Total held-to-maturity securities $ 12,663,455 $ 12,923 $ (128,098 ) $ 12,548,280 (1) Consists of pools of Small Business Investment Company debentures issued and guaranteed by the U.S. Small Business Administration, an independent agency of the United States. December 31, 2016 (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Held-to-maturity securities, at cost: U.S. agency debentures (1) $ 622,445 $ 7,840 $ (1,198 ) $ 629,087 Residential mortgage-backed securities: Agency-issued mortgage-backed securities 2,896,179 6,919 (24,526 ) 2,878,572 Agency-issued collateralized mortgage obligations—fixed rate 3,362,598 788 (31,274 ) 3,332,112 Agency-issued collateralized mortgage obligations—variable rate 312,665 176 (1,339 ) 311,502 Agency-issued commercial mortgage-backed securities 1,151,363 1,237 (7,638 ) 1,144,962 Municipal bonds and notes 81,748 8 (1,853 ) 79,903 Total held-to-maturity securities $ 8,426,998 $ 16,968 $ (67,828 ) $ 8,376,138 (1) Consists of pools of Small Business Investment Company debentures issued and guaranteed by the U.S. Small Business Administration, an independent agency of the United States. The following tables summarize our unrealized losses on our HTM securities portfolio into categories of less than 12 months and 12 months or longer as of December 31, 2017 and 2016 : December 31, 2017 Less than 12 months 12 months or longer (1) Total (Dollars in thousands) Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Held-to-maturity securities: U.S. agency debentures $ 104,688 $ (1,601 ) $ — $ — $ 104,688 $ (1,601 ) Residential mortgage-backed securities: Agency-issued mortgage-backed securities 4,270,377 (34,092 ) 408,913 (9,436 ) 4,679,290 (43,528 ) Agency-issued collateralized mortgage obligations—fixed rate 1,011,709 (13,631 ) 1,741,614 (40,741 ) 2,753,323 (54,372 ) Agency-issued collateralized mortgage obligations—variable rate — — 9,812 (34 ) 9,812 (34 ) Agency-issued commercial mortgage-backed securities 979,361 (11,566 ) 773,712 (13,997 ) 1,753,073 (25,563 ) Municipal bonds and notes 344,796 (2,103 ) 32,844 (897 ) 377,640 (3,000 ) Total temporarily impaired securities (1) $ 6,710,931 $ (62,993 ) $ 2,966,895 $ (65,105 ) $ 9,677,826 $ (128,098 ) (1) As of December 31, 2017 , we identified a total of 753 investments that were in unrealized loss positions, of which 237 investments totaling $3.0 billion with unrealized losses of $65.1 million have been in an impaired position for a period of time greater than 12 months. As of December 31, 2017 , we do not intend to sell any of our impaired securities prior to recovery of our adjusted cost basis, and it is more likely than not that we will not be required to sell any of our securities prior to recovery of our adjusted cost basis, which is consistent with our classification of these securities. Based on our analysis as of December 31, 2017 , we deem all impairments to be temporary. Market valuations and impairment analyses on assets in the HTM securities portfolio are reviewed and monitored on a quarterly basis. December 31, 2016 Less than 12 months 12 months or longer (1) Total (Dollars in thousands) Fair Value of Unrealized Fair Value of Unrealized Fair Value of Unrealized Held-to-maturity securities: U.S. agency debentures $ 118,721 $ (1,198 ) $ — $ — $ 118,721 $ (1,198 ) Residential mortgage-backed securities: Agency-issued mortgage-backed securities 1,801,861 (23,558 ) 21,917 (968 ) 1,823,778 (24,526 ) Agency-issued collateralized mortgage obligations—fixed rate 2,729,889 (25,723 ) 228,220 (5,551 ) 2,958,109 (31,274 ) Agency-issued collateralized mortgage obligations—variable rate 251,012 (1,339 ) — — 251,012 (1,339 ) Agency-issued commercial mortgage-backed securities 999,440 (7,494 ) 14,934 (144 ) 1,014,374 (7,638 ) Municipal bonds and notes 42,267 (877 ) 30,586 (976 ) 72,853 (1,853 ) Total temporarily impaired securities (1) $ 5,943,190 $ (60,189 ) $ 295,657 $ (7,639 ) $ 6,238,847 $ (67,828 ) (1) As of December 31, 2016 , we identified a total of 462 investments that were in unrealized loss positions, of which 85 investments totaling $295.7 million with unrealized losses of $7.6 million have been in an impaired position for a period of time greater than 12 months. The following table summarizes the remaining contractual principal maturities on fixed income investment securities classified as HTM as of December 31, 2017 . For U.S. agency debentures, the expected maturity is the actual contractual maturity of the notes. Expected maturities for mortgage-backed securities may differ significantly from their contractual maturities because mortgage borrowers have the right to prepay outstanding loan obligations with or without penalties. Mortgage-backed securities classified as HTM typically have original contractual maturities from 10 to 30 years whereas expected average lives of these securities tend to be significantly shorter and vary based upon structure and prepayments in lower rate environments. December 31, 2017 Total One Year or Less After One Year to Five Years After Five Years to Ten Years After Ten Years (Dollars in thousands) Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value U.S. agency debentures $ 659,979 $ 661,545 $ — $ — $ 102,496 $ 102,739 $ 557,483 $ 558,806 $ — $ — Residential mortgage-backed securities: Agency-issued mortgage-backed securities 6,304,969 6,266,295 728 723 226,997 225,149 56,380 55,697 6,020,864 5,984,726 Agency-issued collateralized mortgage obligations - fixed rate 2,829,979 2,775,630 — — — — 462,533 451,069 2,367,446 2,324,561 Agency-issued collateralized mortgage obligations - variable rate 255,782 256,481 — — — — — — 255,782 256,481 Agency-issued commercial mortgage-backed securities 1,868,985 1,844,116 — — — — — — 1,868,985 1,844,116 Municipal bonds and notes 743,761 744,213 7,073 7,054 73,054 72,261 233,728 233,257 429,906 431,641 Total $ 12,663,455 $ 12,548,280 $ 7,801 $ 7,777 $ 402,547 $ 400,149 $ 1,310,124 $ 1,298,829 $ 10,942,983 $ 10,841,525 Non-marketable and Other Securities The major components of our non-marketable and other investment securities portfolio at December 31, 2017 and 2016 are as follows: (Dollars in thousands) December 31, 2017 December 31, 2016 Non-marketable and other securities: Non-marketable securities (fair value accounting): Venture capital and private equity fund investments (1) $ 127,192 $ 141,649 Other venture capital investments (2) 919 2,040 Other securities (fair value accounting) (3) 310 753 Non-marketable securities (equity method accounting) (4): Venture capital and private equity fund investments 89,809 82,823 Debt funds 21,183 17,020 Other investments 111,198 123,514 Non-marketable securities (cost method accounting): Venture capital and private equity fund investments (5) 98,548 114,606 Other investments 27,680 27,700 Investments in qualified affordable housing projects, net (6) 174,214 112,447 Total non-marketable and other securities $ 651,053 $ 622,552 (1) The following table shows the amounts of venture capital and private equity fund investments held by the following consolidated funds and our ownership percentage of each fund at December 31, 2017 and 2016 (fair value accounting): December 31, 2017 December 31, 2016 (Dollars in thousands) Amount Ownership % Amount Ownership % Strategic Investors Fund, LP $ 14,673 12.6 % $ 18,459 12.6 % Capital Preferred Return Fund, LP 54,147 20.0 57,627 20.0 Growth Partners, LP 58,372 33.0 59,718 33.0 Other private equity fund (i) — — 5,845 58.2 Total venture capital and private equity fund investments $ 127,192 $ 141,649 (i) At December 31, 2016, we had direct ownership interest of 41.5 percent in one other private equity fund and an indirect ownership interest of 12.6 percent through our ownership interest of Growth Partners, LP and an indirect ownership interest of 4.1 percent through our ownership interest of Capital Preferred Return Fund, LP. On January 3, 2017, such other private equity fund was closed resulting in an immaterial impact on the Company's financial statements. (2) The following table shows the amounts of other venture capital investments held by the following consolidated funds and our ownership percentage of each fund at December 31, 2017 and 2016 (fair value accounting): December 31, 2017 December 31, 2016 (Dollars in thousands) Amount Ownership % Amount Ownership % CP I, LP $ 919 10.7 % $ 2,040 10.7 % Total other venture capital investments $ 919 $ 2,040 (3) Investments classified as other securities (fair value accounting) represent direct equity investments in public companies held by our consolidated funds. (4) The following table shows the carrying value and our ownership percentage of each investment at December 31, 2017 and 2016 (equity method accounting): December 31, 2017 December 31, 2016 (Dollars in thousands) Amount Ownership % Amount Ownership % Venture capital and private equity fund investments: Strategic Investors Fund II, LP $ 6,342 8.6 % $ 7,720 8.6 % Strategic Investors Fund III, LP 18,758 5.9 20,449 5.9 Strategic Investors Fund IV, LP 25,551 5.0 24,530 5.0 Strategic Investors Fund V funds 16,856 Various 12,029 Various CP II, LP (i) 6,700 5.1 7,798 5.1 Other venture capital and private equity fund investments 15,602 Various 10,297 Various Total venture capital and private equity fund investments $ 89,809 $ 82,823 Debt funds: Gold Hill Capital 2008, LP (ii) $ 18,690 15.5 % $ 13,557 15.5 % Other debt funds 2,493 Various 3,463 Various Total debt funds $ 21,183 $ 17,020 Other investments: SPD Silicon Valley Bank Co., Ltd. $ 75,337 50.0 % $ 75,296 50.0 % Other investments 35,861 Various 48,218 Various Total other investments $ 111,198 $ 123,514 (i) Our ownership includes direct ownership of 1.3 percent and indirect ownership interest of 3.8 percent through our investments in Strategic Investors Fund II, LP. (ii) Our ownership includes direct ownership interest of 11.5 percent in the fund and an indirect interest in the fund through our investment in Gold Hill Capital 2008, LLC of 4.0 percent . (5) Represents investments in 235 and 252 funds (primarily venture capital funds) at December 31, 2017 and 2016 , respectively, where our ownership interest is less than five percent of the voting interests of each such fund and in which we do not have the ability to exercise significant influence over the partnerships operating activities and financial policies. The carrying value, and estimated fair value, of these venture capital and private equity fund investments (cost method accounting) was $99 million , and $202 million , respectively, as of December 31, 2017 . The carrying value, and estimated fair value, of the venture capital and private equity fund investments (cost method accounting) was $115 million , and $222 million , respectively, as of December 31, 2016 . (6) The following table presents the balances of our investments in qualified affordable housing projects and related unfunded commitments included as a component of "other liabilities" on our consolidated balance sheets at December 31, 2017 and 2016 : (Dollars in thousands) December 31, 2017 December 31, 2016 Investments in qualified affordable housing projects, net $ 174,214 $ 112,447 Other liabilities 100,891 58,095 The following table presents other information relating to our investments in qualified affordable housing projects for the year ended December 31, 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Tax credits and other tax benefits recognized $ 17,296 $ 15,404 $ 14,375 Amortization expense included in provision for income taxes (i) 17,362 12,145 10,389 (i) All investments are amortized using the proportional amortization method and amortization expense is included in the provision for income taxes. Included in amortization expense for the year ended December 31, 2017 is a one-time cumulative effect adjustment of $3.8 million due to the decrease in value of deductions in the 2018 tax year and going forward, due to the TCJ Act federal corporate income tax rate reduction. The following table presents the components of gains and losses (realized and unrealized) on investment securities in 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Gross gains on investment securities: Available-for-sale securities, at fair value (1) $ 5,113 $ 15,051 $ 2,971 Non-marketable securities (fair value accounting): Venture capital and private equity fund investments 34,093 25,041 32,399 Other venture capital investments 1,114 17 1,512 Other securities (fair value accounting) 991 691 9,180 Non-marketable securities (equity method accounting): Venture capital and private equity fund investments 15,013 10,834 26,415 Debt funds 11,658 1,406 4,111 Other investments 3,181 15,739 2,791 Non-marketable securities (cost method accounting): Venture capital and private equity fund investments 21,718 18,428 25,908 Other investments 4,111 293 2,599 Total gross gains on investment securities 96,992 87,500 107,886 Gross losses on investment securities: Available-for-sale securities, at fair value (1) (10,302 ) (2,856 ) (1,770 ) Non-marketable securities (fair value accounting): Venture capital and private equity fund investments (6,907 ) (19,077 ) (9,210 ) Other venture capital investments (143 ) (38 ) (320 ) Other securities (fair value accounting) (750 ) (781 ) (1,559 ) Non-marketable securities (equity method accounting): Venture capital and private equity fund investments (541 ) (6,764 ) (909 ) Debt funds (2,708 ) (458 ) (774 ) Other investments (9,457 ) (4,857 ) (3,146 ) Non-marketable securities (cost method accounting): Venture capital and private equity fund investments (2) (1,312 ) (591 ) (729 ) Other investments (3) (269 ) (338 ) (24 ) Total gross losses on investment securities (32,389 ) (35,760 ) (18,441 ) Gains on investment securities, net $ 64,603 $ 51,740 $ 89,445 (1) Includes realized gains and losses on sales of AFS securities that are recognized in the income statement. Unrealized gains and losses on AFS securities are recognized in other comprehensive income. The cost basis of AFS securities sold is determined on a specific identification basis. (2) Includes OTTI of $1.3 million from the declines in value for 24 of the 235 investments held at December 31, 2017 , $0.6 million from the declines in value for 26 of the 252 investments held at December 31, 2016 and $0.6 million from the declines in value for 22 of the 267 investments held at December 31, 2015 . We concluded that any declines in value for the remaining investments were temporary, and as such, no OTTI was required to be recognized. (3) No OTTI was recognized for the years ended December 31, 2017 , 2016 , and 2015 , respectively. We concluded that any declines in value for the investments were temporary, and as such, no OTTI was required to be recognized.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Loans and Allowance for Loan Losses	Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments We serve a variety of commercial clients in the technology, life science/healthcare, private equity/venture capital and premium wine industries. Our technology clients generally tend to be in the industries of hardware (semiconductors, communications, data, storage, and electronics), software/internet (such as infrastructure software, applications, software services, digital content and advertising technology), and energy and resource innovation ("ERI"). Because of the diverse nature of ERI products and services, for our loan-related reporting purposes, ERI-related loans are reported under our hardware, software/internet, life science/healthcare and other commercial loan categories, as applicable. Our life science/healthcare clients primarily tend to be in the industries of biotechnology, medical devices, healthcare information technology and healthcare services. Loans made to private equity/venture capital firm clients typically enable them to fund investments prior to their receipt of funds from capital calls. Loans to the premium wine industry focus on vineyards and wineries that produce grapes and wines of high quality. In addition to commercial loans, we make consumer loans through SVB Private Bank and provide real estate secured loans to eligible employees through our EHOP. Our private banking clients are primarily private equity/venture capital professionals and executive leaders in the innovation companies they support. These products and services include real estate secured home equity lines of credit, which may be used to finance real estate investments and loans used to purchase, renovate or refinance personal residences. These products and services also include restricted stock purchase loans and capital call lines of credit. We also provide community development loans made as part of our responsibilities under the Community Reinvestment Act. These loans are included within “Construction loans” below and are primarily secured by real estate. The composition of loans, net of unearned income of $148 million and $125 million at December 31, 2017 and 2016 , respectively, is presented in the following table: December 31, (Dollars in thousands) 2017 2016 Commercial loans: Software/internet $ 6,172,531 $ 5,627,031 Hardware 1,193,599 1,180,398 Private equity/venture capital 9,952,377 7,691,148 Life science/healthcare 1,808,827 1,853,004 Premium wine 204,105 200,156 Other 365,724 393,551 Total commercial loans 19,697,163 16,945,288 Real estate secured loans: Premium wine (1) 669,053 678,166 Consumer loans (2) 2,300,506 1,926,968 Other 42,068 43,487 Total real estate secured loans 3,011,627 2,648,621 Construction loans 68,546 64,671 Consumer loans 328,980 241,364 Total loans, net of unearned income (3) $ 23,106,316 $ 19,899,944 (1) Included in our premium wine portfolio are gross construction loans of $100 million and $110 million at December 31, 2017 and 2016 , respectively. (2) Consumer loans secured by real estate at December 31, 2017 and 2016 were comprised of the following: December 31, (Dollars in thousands) 2017 2016 Loans for personal residence $ 1,995,840 $ 1,655,349 Loans to eligible employees 243,118 199,291 Home equity lines of credit 61,548 72,328 Consumer loans secured by real estate $ 2,300,506 $ 1,926,968 (3) Included within our total loan portfolio are credit card loans of $270 million and $224 million at December 31, 2017 and 2016 , respectively. Credit Quality The composition of loans, net of unearned income of $148 million and $125 million at December 31, 2017 and 2016 , respectively, broken out by portfolio segment and class of financing receivable, is as follows: December 31, (Dollars in thousands) 2017 2016 Commercial loans: Software/internet $ 6,172,531 $ 5,627,031 Hardware 1,193,599 1,180,398 Private equity/venture capital 9,952,377 7,691,148 Life science/healthcare 1,808,827 1,853,004 Premium wine 873,158 878,322 Other 476,338 501,709 Total commercial loans 20,476,830 17,731,612 Consumer loans: Real estate secured loans 2,300,506 1,926,968 Other consumer loans 328,980 241,364 Total consumer loans 2,629,486 2,168,332 Total loans, net of unearned income $ 23,106,316 $ 19,899,944 The following table summarizes the aging of our gross loans, broken out by portfolio segment and class of financing receivable as of December 31, 2017 and 2016 : (Dollars in thousands) 30 - 59 Days Past Due 60 - 89 Days Past Due Equal to or Greater Than 90 Days Past Due Total Past Due Current Loans Past Due 90 Days or More Still Accruing Interest December 31, 2017: Commercial loans: Software/internet $ 14,257 $ 6,526 $ 141 $ 20,924 $ 6,101,147 $ 141 Hardware 1,145 77 50 1,272 1,163,278 50 Private equity/venture capital 86,566 38,580 — 125,146 9,835,317 — Life science/healthcare 4,390 191 — 4,581 1,841,692 — Premium wine 418 — — 418 871,074 — Other 445 — — 445 490,292 — Total commercial loans 107,221 45,374 191 152,786 20,302,800 191 Consumer loans: Real estate secured loans 2,164 532 — 2,696 2,292,980 — Other consumer loans 796 — — 796 327,234 — Total consumer loans 2,960 532 — 3,492 2,620,214 — Total gross loans excluding impaired loans 110,181 45,906 191 156,278 22,923,014 191 Impaired loans 1,344 11,902 30,403 43,649 131,212 — Total gross loans $ 111,525 $ 57,808 $ 30,594 $ 199,927 $ 23,054,226 $ 191 December 31, 2016: Commercial loans: Software/internet $ 37,087 $ 1,162 $ 6 $ 38,255 $ 5,507,575 $ 6 Hardware 5,591 36 27 5,654 1,118,065 27 Private equity/venture capital 689 — — 689 7,747,222 — Life science/healthcare 283 551 — 834 1,827,490 — Premium wine 1,003 4 — 1,007 876,185 — Other 34 300 — 334 504,021 — Total commercial loans 44,687 2,053 33 46,773 17,580,558 33 Consumer loans: Real estate secured loans 850 — — 850 1,923,266 — Other consumer loans 1,402 — — 1,402 237,353 — Total consumer loans 2,252 — — 2,252 2,160,619 — Total gross loans excluding impaired loans 46,939 2,053 33 49,025 19,741,177 33 Impaired loans 34,636 3,451 11,180 49,267 185,193 — Total gross loans $ 81,575 $ 5,504 $ 11,213 $ 98,292 $ 19,926,370 $ 33 The following table summarizes our impaired loans as they relate to our allowance for loan losses, broken out by portfolio segment and class of financing receivable for the years ended December 31, 2017 and 2016 : (Dollars in thousands) Impaired loans for which there is a related allowance for loan losses Impaired loans for which there is no related allowance for loan losses Total carrying value of impaired loans Total unpaid principal of impaired loans December 31, 2017: Commercial loans: Software/internet $ 49,645 $ 61,009 $ 110,654 $ 129,006 Hardware 15,637 20,713 36,350 41,721 Private equity/venture capital 658 — 658 984 Life science/healthcare 20,521 1,166 21,687 26,360 Premium wine — 2,877 2,877 2,911 Other 32 — 32 165 Total commercial loans 86,493 85,765 172,258 201,147 Consumer loans: Real estate secured loans 1,331 850 2,181 3,712 Other consumer loans 422 — 422 436 Total consumer loans 1,753 850 2,603 4,148 Total $ 88,246 $ 86,615 $ 174,861 $ 205,295 December 31, 2016: Commercial loans: Software/internet $ 121,658 $ 1,090 $ 122,748 $ 129,648 Hardware 65,395 — 65,395 70,683 Private equity/venture capital — — — — Life science/healthcare 38,361 — 38,361 41,130 Premium wine 3,187 — 3,187 3,187 Other 867 — 867 867 Total commercial loans 229,468 1,090 230,558 245,515 Consumer loans: Real estate secured loans 1,504 — 1,504 2,779 Other consumer loans 2,398 — 2,398 2,398 Total consumer loans 3,902 — 3,902 5,177 Total $ 233,370 $ 1,090 $ 234,460 $ 250,692 The following table summarizes our average impaired loans and interest income on impaired loans, broken out by portfolio segment and class of financing receivable during 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) Average impaired loans Interest income on impaired loans 2017 2016 2015 2017 2016 2015 Commercial loans: Software/internet $ 119,557 $ 89,462 $ 63,825 $ 2,263 $ 1,054 $ 344 Hardware 35,022 39,108 8,854 1,061 2,624 574 Private equity/venture capital 556 — — — — — Life science/healthcare 30,842 40,620 18,083 90 155 132 Premium wine 3,249 2,056 1,455 152 28 12 Other 576 3,442 2,758 — 6 8 Total commercial loans 189,802 174,688 94,975 3,566 3,867 1,070 Consumer loans: Real estate secured loans 1,514 588 172 — — — Other consumer loans 1,804 1,136 41 — 17 — Total consumer loans 3,318 1,724 213 — 17 — Total average impaired loans $ 193,120 $ 176,412 $ 95,188 $ 3,566 $ 3,884 $ 1,070 The following tables summarize the activity relating to our allowance for loan losses for 2017 , 2016 and 2015 broken out by portfolio segment: Year ended December 31, 2017 (Dollars in thousands) Beginning Balance December 31, 2016 Charge-offs Recoveries Provision for (Reduction of) Loan Losses Foreign Currency Translation Adjustments Ending Balance December 31, 2017 Commercial loans: Software/internet $ 97,388 $ (45,012 ) $ 4,649 $ 38,462 $ 617 $ 96,104 Hardware 31,166 (10,414 ) 487 6,051 324 27,614 Private equity/venture capital 50,299 (323 ) — 31,625 867 82,468 Life science/healthcare 25,446 (8,210 ) 189 7,414 85 24,924 Premium wine 4,115 — — (540 ) (43 ) 3,532 Other 4,768 (1,156 ) 1,850 (1,459 ) (62 ) 3,941 Total commercial loans 213,182 (65,115 ) 7,175 81,553 1,788 238,583 Consumer loans 12,184 (1,567 ) 1,363 4,386 75 16,441 Total allowance for loan losses $ 225,366 $ (66,682 ) $ 8,538 $ 85,939 $ 1,863 $ 255,024 Year ended December 31, 2016 (Dollars in thousands) Beginning Balance December 31, 2015 Charge-offs Recoveries Provision for (Reduction of) Loan Losses Foreign Currency Translation Adjustments Ending Balance December 31, 2016 Commercial loans: Software/internet $ 103,045 $ (68,784 ) $ 7,278 $ 58,350 $ (2,501 ) $ 97,388 Hardware 23,085 (13,233 ) 1,667 20,851 (1,204 ) 31,166 Private equity/venture capital 35,282 — — 15,114 (97 ) 50,299 Life science/healthcare 36,576 (9,693 ) 1,129 (2,543 ) (23 ) 25,446 Premium wine 5,205 — — (1,260 ) 170 4,115 Other 4,252 (5,045 ) 1,880 3,373 308 4,768 Total commercial loans 207,445 (96,755 ) 11,954 93,885 (3,347 ) 213,182 Consumer loans 10,168 (102 ) 258 1,812 48 12,184 Total allowance for loan losses $ 217,613 $ (96,857 ) $ 12,212 $ 95,697 $ (3,299 ) $ 225,366 Year ended December 31, 2015 Beginning Balance December 31, 2014 Charge-offs Recoveries Provision for (Reduction of) Loan Losses Foreign Currency Translation Adjustments Ending Balance December 31, 2015 Commercial loans: Software/internet $ 80,981 $ (33,246 ) $ 1,621 $ 53,696 $ (7 ) $ 103,045 Hardware 25,860 (5,145 ) 3,332 (1,035 ) 73 23,085 Private equity/venture capital 27,997 — — 7,391 (106 ) 35,282 Life science/healthcare 15,208 (7,291 ) 277 28,400 (18 ) 36,576 Premium wine 4,473 — 7 725 — 5,205 Other 3,253 (4,990 ) 809 5,736 (556 ) 4,252 Total commercial loans 157,772 (50,672 ) 6,046 94,913 (614 ) 207,445 Consumer loans 7,587 (296 ) 163 2,716 (2 ) 10,168 Total allowance for loan losses $ 165,359 $ (50,968 ) $ 6,209 $ 97,629 $ (616 ) $ 217,613 The following table summarizes the activity relating to our allowance for unfunded credit commitments for 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Allowance for unfunded credit commitments, beginning balance $ 45,265 $ 34,415 $ 36,419 Provision for (reduction of) unfunded credit commitments 6,365 10,982 (1,946 ) Foreign currency translation adjustments 140 (132 ) (58 ) Allowance for unfunded credit commitments, ending balance (1) $ 51,770 $ 45,265 $ 34,415 (1) See Note 19—“Off-Balance Sheet Arrangements, Guarantees and Other Commitments” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report for additional disclosures related to our commitments to extend credit. The following table summarizes the allowance for loan losses individually and collectively evaluated for impairment as of December 31, 2017 and 2016 , broken out by portfolio segment: December 31, 2017 December 31, 2016 Individually Evaluated for Impairment Collectively Evaluated for Impairment Individually Evaluated for Impairment Collectively Evaluated for Impairment (Dollars in thousands) Allowance for loan losses Recorded investment in loans Allowance for loan losses Recorded investment in loans Allowance for loan losses Recorded investment in loans Allowance for loan losses Recorded investment in loans Commercial loans: Software/internet $ 23,088 $ 110,654 $ 73,016 $ 6,061,877 $ 28,245 $ 122,748 $ 69,143 $ 5,504,283 Hardware 8,450 36,350 19,164 1,157,249 9,995 65,395 21,171 1,115,003 Private equity/venture capital 330 658 82,138 9,951,719 — — 50,299 7,691,148 Life science/healthcare 9,315 21,687 15,609 1,787,140 8,709 38,361 16,737 1,814,643 Premium wine — 2,877 3,532 870,281 520 3,187 3,595 875,135 Other 32 32 3,909 476,306 233 867 4,535 500,842 Total commercial loans 41,215 172,258 197,368 20,304,572 47,702 230,558 165,480 17,501,054 Total consumer loans 578 2,603 15,863 2,626,883 1,123 3,902 11,061 2,164,430 Total $ 41,793 $ 174,861 $ 213,231 $ 22,931,455 $ 48,825 $ 234,460 $ 176,541 $ 19,665,484 Credit Quality Indicators For each individual client, we establish an internal credit risk rating for that loan, which is used for assessing and monitoring credit risk as well as performance of the loan and the overall portfolio. Our internal credit risk ratings are also used to summarize the risk of loss due to failure by an individual borrower to repay the loan. For our internal credit risk ratings, each individual loan is given a risk rating of 1 through 10. Loans risk-rated 1 through 4 are performing loans and translate to an internal rating of “Pass”, with loans risk-rated 1 being cash secured. Loans risk-rated 5 through 7 are performing loans, however, we consider them as demonstrating higher risk, which requires more frequent review of the individual exposures; these translate to an internal rating of “Performing (Criticized)”. When full repayment of a criticized loan has been deemed improbable under the original contractual terms but full repayment remains probable overall, the loan is considered to be a “Performing Impaired (Criticized)” loan. The loan is also considered for nonaccrual status if full repayment is determined to be improbable. All of our nonaccrual loans are risk-rated 8 or 9 and are classified under the nonperforming impaired category. (For a further description of nonaccrual loans, refer to Note 2—“Summary of Significant Accounting Policies” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report ). Loans rated 10 are charged-off and are not included as part of our loan portfolio balance. We review our credit quality indicators for performance and appropriateness of risk ratings as part of our evaluation process for our allowance for loan losses. The following table summarizes the credit quality indicators, broken out by portfolio segment and class of financing receivables as of December 31, 2017 and 2016 : (Dollars in thousands) Pass Performing (Criticized) Performing Impaired (Criticized) Nonperforming Impaired (Nonaccrual) Total December 31, 2017: Commercial loans: Software/internet $ 5,655,739 $ 466,332 $ 31,794 $ 78,860 $ 6,232,725 Hardware 1,112,574 51,976 20,165 16,185 1,200,900 Private equity/venture capital 9,955,082 5,381 — 658 9,961,121 Life science/healthcare 1,720,613 125,660 1,167 20,520 1,867,960 Premium wine 834,537 36,955 2,476 401 874,369 Other 469,721 21,016 — 32 490,769 Total commercial loans 19,748,266 707,320 55,602 116,656 20,627,844 Consumer loans: Real estate secured loans 2,282,375 13,301 — 2,181 2,297,857 Other consumer loans 326,851 1,179 — 422 328,452 Total consumer loans 2,609,226 14,480 — 2,603 2,626,309 Total gross loans $ 22,357,492 $ 721,800 $ 55,602 $ 119,259 $ 23,254,153 December 31, 2016: Commercial loans: Software/internet $ 4,924,923 $ 620,907 $ 46,143 $ 76,605 $ 5,668,578 Hardware 985,889 137,830 58,814 6,581 1,189,114 Private equity/venture capital 7,747,317 594 — — 7,747,911 Life science/healthcare 1,707,499 120,825 6,578 31,783 1,866,685 Premium wine 865,354 11,838 2,696 491 880,379 Other 480,845 23,510 464 403 505,222 Total commercial loans 16,711,827 915,504 114,695 115,863 17,857,889 Consumer loans: Real estate secured loans 1,914,512 9,604 — 1,504 1,925,620 Other consumer loans 238,256 499 786 1,612 241,153 Total consumer loans 2,152,768 10,103 786 3,116 2,166,773 Total gross loans $ 18,864,595 $ 925,607 $ 115,481 $ 118,979 $ 20,024,662 Troubled Debt Restructurings As of December 31, 2017 we had 22 TDRs with a total carrying value of $147.8 million where concessions have been granted to borrowers experiencing financial difficulties, in an attempt to maximize collection. This compares to 20 TDRs with a total carrying value of $96.1 million as of December 31, 2016 . There were unfunded commitments available for funding of $0.6 million to the clients associated with these TDRs as of December 31, 2017 . The following table summarizes our loans modified in TDRs, broken out by portfolio segment and class of financing receivables at December 31, 2017 and 2016 : December 31, (Dollars in thousands) 2017 2016 Loans modified in TDRs: Commercial loans: Software/internet $ 73,455 $ 52,646 Hardware 51,132 14,870 Private equity/venture capital 350 — Life science/healthcare 19,235 24,176 Premium wine 3,198 3,194 Other — 387 Total commercial loans 147,370 95,273 Consumer loans: Other consumer loans 423 786 Total loans modified in TDRs $ 147,793 $ 96,059 The following table summarizes the recorded investment in loans modified in TDRs, broken out by portfolio segment and class of financing receivable, for modifications made during 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Loans modified in TDRs during the period: Commercial loans: Software/internet $ 42,184 $ 23,574 $ 56,790 Hardware 51,132 14,870 286 Private equity/venture capital 350 — — Life science/healthcare — 1,638 51,878 Premium wine 177 677 898 Other — — 519 Total commercial loans 93,843 40,759 110,371 Consumer loans: Other consumer loans — 786 — Total loans modified in TDRs during the period (1) $ 93,843 $ 41,545 $ 110,371 (1) During 2017 , we had $3.0 million of partial charge-offs on loans classified as TDRs. We had $3.6 million of partial charge-offs in 2016 and $23.5 million of partial charge-offs in 2015. During 2017 , $93.5 million of new TDRs were modified through payment deferrals granted to our clients and $0.3 million were modified through partial forgiveness of principal. During 2016 and 2015, all new TDRs were modified through payment deferrals granted to our clients. The related allowance for loan losses for the majority of our TDRs is determined on an individual basis by comparing the carrying value of the loan to the present value of the estimated future cash flows, discounted at the pre-modification contractual interest rate. For certain TDRs, the related allowance for loan losses is determined based on the fair value of the collateral if the loan is collateral dependent. The following table summarizes the recorded investment in loans modified in TDRs within the previous 12 months that subsequently defaulted during their respective periods, broken out by portfolio segment and class of financing receivable, during 2017 , 2016 and 2015 : December 31, (Dollars in thousands) 2017 (1) 2016 2015 TDRs modified within the previous 12 months that defaulted during the period: Commercial loans: Software/internet $ — $ — $ 16,804 Hardware — 134 286 Premium wine — 491 — Life science/healthcare — — 943 Total commercial loans — 625 18,033 Consumer loans: Other consumer loans — 786 — Total TDRs modified within the previous 12 months that defaulted in the period $ — $ 1,411 $ 18,033 (1) There were no loans modified in TDRs within the previous 12 months that subsequently defaulted during 2017 . Charge-offs and defaults on previously restructured loans are evaluated to determine the impact to the allowance for loan losses, if any. The evaluation of these defaults may impact the assumptions used in calculating the reserve on other TDRs and impaired loans as well as management’s overall outlook of macroeconomic factors that affect the reserve on the loan portfolio as a whole. After evaluating the charge-offs and defaults experienced on our TDRs we determined that no change to our reserving methodology was necessary to determine the allowance for loan losses as of December 31, 2017 .

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment Premises and equipment at December 31, 2017 and 2016 consisted of the following: December 31, (Dollars in thousands) 2017 2016 Computer software $ 203,359 $ 189,867 Computer hardware 63,881 56,215 Leasehold improvements 89,225 70,909 Furniture and equipment 38,146 31,886 Total 394,611 348,877 Accumulated depreciation and amortization (265,929 ) (228,194 ) Premises and equipment, net $ 128,682 $ 120,683 Depreciation and amortization expense for premises and equipment was $38.0 million , $33.9 million and $28.3 million in 2017 , 2016 and 2015 , respectively.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Deposits	Deposits The following table presents the composition of our deposits at December 31, 2017 and 2016 : December 31, (Dollars in thousands) 2017 2016 Noninterest-bearing demand $ 36,655,497 $ 31,975,457 Interest bearing checking and savings accounts 556,121 375,710 Money market 5,975,220 5,331,054 Money market deposits in foreign offices 111,201 107,657 Sweep deposits in foreign offices 908,890 1,133,872 Time 47,146 56,118 Total deposits $ 44,254,075 $ 38,979,868 The aggregate amount of time deposit accounts individually equal to or greater than $250,000 totaled $37 million and $43 million at December 31, 2017 and 2016 , respectively. At December 31, 2017 , time deposit accounts individually equal to or greater than $250,000 totaling $37 million were scheduled to mature within one year.

Short-Term Borrowings and Long-

Short-Term Borrowings and Long-Term Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Short-Term Borrowings and Long-Term Debt	Short-Term Borrowings and Long-Term Debt The following table represents outstanding short-term borrowings and long-term debt at December 31, 2017 and 2016 : Carrying Value (Dollars in thousands) Maturity Principal value at December 31, 2017 December 31, December 31, Short-term borrowings: Short-term FHLB advances January 2, 2018 $ 700,000 $ 700,000 $ 500,000 Federal funds purchased January 2, 2018 330,000 330,000 — Other short-term borrowings (1) 3,730 3,730 12,668 Total short-term borrowings $ 1,033,730 $ 512,668 Long-term debt: 3.50% Senior Notes January 29, 2025 $ 350,000 $ 347,303 $ 346,979 5.375% Senior Notes September 15, 2020 350,000 348,189 347,586 6.05% Subordinated Notes (2) — — 46,646 7.0% Junior Subordinated Debentures (3) — — 54,493 Total long-term debt $ 695,492 $ 795,704 (1) Represents cash collateral received from certain counterparties in relation to market value exposures of derivative contracts in our favor. (2) Our 6.05% Subordinated Notes were repaid on June 1, 2017 and the interest rate swap agreement related to this issuance was terminated upon repayment of the 6.05% Subordinated Notes. At December 31, 2016, included in the carrying value of our 6.05% Subordinated Notes were $0.8 million related to hedge accounting associated with the notes. (3) On December 21, 2017, we redeemed in full the outstanding aggregate principal amount of $51.5 million of our 7.0% Junior Subordinated Debentures due October 15, 2033, relating to our 7.0% Cumulative Trust Preferred Securities issued by SVB Capital II. The aggregate annual maturities of long-term debt obligations as of December 31, 2017 are as follows: Year ended December 31, (Dollars in thousands): Amount 2018 $ — 2019 — 2020 348,189 2021 — 2022 — 2023 and thereafter 347,303 Total $ 695,492 Interest expense related to short-term borrowings and long-term debt was $36.1 million , $37.3 million and $34.9 million in 2017 , 2016 and 2015 , respectively. Interest expense is net of the hedge accounting impact from our interest rate swap agreements related to our 6.05% Subordinated Notes. The weighted average interest rate associated with our short-term borrowings was 1.39 percent as of December 31, 2017 and 0.59 percent as of December 31, 2016 . 3.50% Senior Notes In January 2015, SVB Financial issued $350 million of 3.50% Senior Notes due in January 2025. We received net proceeds of approximately $346.4 million after deducting underwriting discounts and commissions and issuance costs. The balance of our 3.50% Senior Notes at December 31, 2017 was $347.3 million , which is reflective of $3.0 million of debt issuance costs and a $0.3 million discount. 5.375% Senior Notes In September 2010, SVB Financial issued $350 million of 5.375% Senior Notes due in September 2020. We received net proceeds of $345 million after deducting underwriting discounts and commissions and other expenses. We used approximately $250 million of the net proceeds from the sale of the notes to meet obligations due on our 3.875% Convertible Notes, which matured in April 2011. The remaining net proceeds were used for general corporate purposes, including working capital. 6.05% Subordinated Notes In May 2007, the Bank issued 6.05% Subordinated Notes, due in June 2017 , in an aggregate principal amount of $250 million ("6.05% Subordinated Notes"). Concurrent with the issuance of the 6.05% Subordinated Notes, we entered into a fixed-to-variable interest rate swap agreement. See Note 13—“Derivative Financial Instruments” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report for additional details. Our 6.05% Subordinated Notes, issued by the Bank, were repaid on June 1, 2017. The interest rate swap agreement relating to this issuance was terminated upon repayment of the notes. 7.0% Junior Subordinated Debentures In October 2003, SVB Financial issued $50 million in 7.0% Junior Subordinated Debentures to a special-purpose trust, SVB Capital II. Distributions to SVB Capital II are cumulative and are payable quarterly at a fixed rate of 7.0% per annum of the face value of the junior subordinated debentures. Distributions for 2017 were $3.3 million and $3.5 million for each of years 2016 and 2015 . The junior subordinated debentures were mandatorily redeemable upon maturity in October 2033, or could be redeemed prior to maturity in whole or in part, at our option, at any time. Issuance costs of $2.2 million related to the junior subordinated debentures were deferred and were being amortized over the period until redemption. On December 21, 2017, we redeemed in full the outstanding aggregate principal amount of $51.5 million of our 7.0% Junior Subordinated Debentures due October 15, 2033, relating to our 7.0% Cumulative Trust Preferred Securities issued by SVB Capital II and the remaining deferred issuance costs were recognized upon redemption. Available Lines of Credit We have certain facilities in place to enable us to access short-term borrowings on a secured (using loans and available-for-sale securities as collateral) and an unsecured basis. These include repurchase agreements and uncommitted federal funds lines with various financial institutions. As of December 31, 2017 , we borrowed $330 million against our uncommitted federal funds lines. We also pledge securities to the FHLB of San Francisco and the discount window at the FRB. The fair value of collateral pledged to the FHLB of San Francisco (comprised primarily of loans and U.S. Treasury securities) at December 31, 2017 totaled $3.4 billion , of which $2.7 billion was available to support additional borrowings. The fair value of collateral pledged at the discount window of the FRB (comprised primarily of U.S. Treasury securities and U.S. agency debentures) at December 31, 2017 totaled $1.0 billion , all of which was unused and available to support additional borrowings.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments We primarily use derivative financial instruments to manage interest rate risk, currency exchange rate risk and to assist customers with their risk management objectives. Also, in connection with negotiating credit facilities and certain other services, we often obtain equity warrant assets giving us the right to acquire stock in private, venture-backed companies in the technology and life science/healthcare industries. Interest Rate Risk Interest rate risk is our primary market risk and can result from timing and volume differences in the repricing of our interest rate sensitive assets and liabilities and changes in market interest rates. To manage interest rate risk for our 6.05% Subordinated Notes, we entered into a fixed-for-floating interest rate swap agreement at the time of debt issuance based upon LIBOR with matched-terms. Net cash benefits associated with our interest rate swap are recorded as a reduction in “Interest expense—Borrowings,” a component of net interest income. The fair value of our interest rate swaps is calculated using a discounted cash flow method and adjusted for credit valuation associated with counterparty risk. Changes in fair value of the interest rate swaps are reflected in either other assets (for swaps in an asset position) or other liabilities (for swaps in a liability position). On June 1, 2017, our interest rate swap was terminated upon repayment of the 6.05% Subordinated Notes. Currency Exchange Risk We enter into foreign exchange forward contracts to economically reduce our foreign exchange exposure risk associated with the net difference between foreign currency denominated assets and liabilities. We do not designate any foreign exchange forward contracts as derivative instruments that qualify for hedge accounting. Gains or losses from changes in currency rates on foreign currency denominated instruments are recorded in the line item "Other" as part of noninterest income, a component of consolidated net income. We may experience ineffectiveness in the economic hedging relationship, because the instruments are revalued based upon changes in the currency’s spot rate on the principal value, while the forwards are revalued on a discounted cash flow basis. We record forward agreements in gain positions in other assets and loss positions in other liabilities, while net changes in fair value are recorded in the line item "Other" as part of noninterest income, a component of consolidated net income. Other Derivative Instruments Also included in our derivative instruments are equity warrant assets and client forward and option contracts, and client interest rate contracts. For further description of these other derivative instruments, refer to Note 2—“Summary of Significant Accounting Policies” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report . Counterparty Credit Risk We are exposed to credit risk if counterparties to our derivative contracts do not perform as expected. We mitigate counterparty credit risk through credit approvals, limits, monitoring procedures and obtaining collateral, as appropriate. With respect to measuring counterparty credit risk for derivative instruments, we measure the fair value of a group of financial assets and financial liabilities on a net risk basis by counterparty portfolio. The total notional or contractual amounts, fair value, collateral and net exposure of our derivative financial instruments at December 31, 2017 and 2016 were as follows: December 31, 2017 December 31, 2016 (Dollars in thousands) Balance Sheet Location Notional or Contractual Amount Fair Value Collateral (1) Net Exposure (2) Notional or Contractual Amount Fair Value Collateral (1) Net Exposure (2) Derivatives designated as hedging instruments: Interest rate risks: Interest rate swaps Other assets $ — $ — $ — $ — $ 45,964 $ 810 $ 89 $ 721 Derivatives not designated as hedging instruments: Currency exchange risks: Foreign exchange forwards Other assets 50,889 414 39 375 219,950 3,057 — 3,057 Foreign exchange forwards Other liabilities 425,055 (5,201 ) — (5,201 ) 54,338 (968 ) — (968 ) Net exposure (4,787 ) 39 (4,826 ) 2,089 — 2,089 Other derivative instruments: Equity warrant assets Other assets 211,253 123,763 — 123,763 211,434 131,123 — 131,123 Other derivatives: Client foreign exchange forwards Other assets 2,203,643 95,035 3,691 91,344 1,251,308 54,587 12,579 42,008 Client foreign exchange forwards Other liabilities 2,092,207 (90,253 ) — (90,253 ) 1,068,991 (43,317 ) — (43,317 ) Client foreign currency options Other assets 102,678 1,187 — 1,187 775,000 10,383 — 10,383 Client foreign currency options Other liabilities 102,678 (1,187 ) — (1,187 ) 775,000 (10,383 ) — (10,383 ) Client interest rate derivatives Other assets 726,984 11,753 — 11,753 583,511 10,110 — 10,110 Client interest rate derivatives Other liabilities 782,586 (11,940 ) — (11,940 ) 627,639 (9,770 ) — (9,770 ) Net exposure 4,595 3,691 904 11,610 12,579 (969 ) Net $ 123,571 $ 3,730 $ 119,841 $ 145,632 $ 12,668 $ 132,964 (1) Cash collateral received from our counterparties in relation to market value exposures of derivative contracts in our favor is recorded as a component of “short-term borrowings” on our consolidated balance sheets. (2) Net exposure for contracts in a gain position reflects the replacement cost in the event of nonperformance by all such counterparties. The credit ratings of our institutional counterparties as of December 31, 2017 remain at investment grade or higher and there were no material changes in their credit ratings for the year ended December 31, 2017. A summary of our derivative activity and the related impact on our consolidated statements of income for 2017 , 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) Statement of income location 2017 2016 2015 Derivatives designated as hedging instruments: Interest rate risks: Net cash benefit associated with interest rate swaps Interest expense—borrowings $ 1,053 $ 2,341 $ 2,526 Changes in fair value of interest rate swaps Other noninterest income (7 ) (35 ) (20 ) Net gains associated with interest rate risk derivatives $ 1,046 $ 2,306 $ 2,506 Derivatives not designated as hedging instruments: Currency exchange risks: Gains (losses) on revaluations of internal foreign currency instruments, net Other noninterest income $ 33,161 $ (16,676 ) $ (12,735 ) (Losses) gains on internal foreign exchange forward contracts, net Other noninterest income (32,286 ) 16,136 12,377 Net gains (losses) associated with internal currency risk $ 875 $ (540 ) $ (358 ) Other derivative instruments: Gains on revaluations of client foreign currency instruments, net Other noninterest income $ 10,882 $ 4,215 $ 115 (Losses) gains on client foreign exchange forward contracts, net Other noninterest income (9,969 ) (5,674 ) 694 Net gains (losses) associated with client currency risk $ 913 $ (1,459 ) $ 809 Net gains on equity warrant assets Gains on equity warrant assets, net $ 54,555 $ 37,892 $ 70,963 Net (losses) gains on other derivatives Other noninterest income $ (564 ) $ 262 $ (209 ) Balance Sheet Offsetting Certain of our derivative and other financial instruments are subject to enforceable master netting arrangements with our counterparties. These agreements provide for the net settlement of multiple contracts with a single counterparty through a single payment, in a single currency, in the event of default on or termination of any one contract. The following table summarizes our assets subject to enforceable master netting arrangements as of December 31, 2017 and 2016 : (Dollars in thousands) Gross Amounts of Recognized Assets Gross Amounts offset in the Statement of Financial Position Net Amounts of Assets Presented in the Statement of Financial Position Gross Amounts Not Offset in the Statement of Financial Position But Subject to Master Netting Arrangements Net Amount Financial Instruments Cash Collateral Received December 31, 2017: Derivative Assets: Interest rate swaps $ — $ — $ — $ — $ — $ — Foreign exchange forwards 95,449 — 95,449 (14,456 ) (3,730 ) 77,263 Foreign currency options 1,187 — 1,187 (557 ) — 630 Client interest rate derivatives 11,753 — 11,753 (11,741 ) — 12 Total derivative assets: 108,389 — 108,389 (26,754 ) (3,730 ) 77,905 Reverse repurchase, securities borrowing, and similar arrangements 247,876 — 247,876 (247,876 ) — — Total $ 356,265 $ — $ 356,265 $ (274,630 ) $ (3,730 ) $ 77,905 December 31, 2016: Derivative Assets: Interest rate swaps $ 810 $ — $ 810 $ (721 ) $ (89 ) $ — Foreign exchange forwards 57,644 — 57,644 (22,738 ) (12,579 ) 22,327 Foreign currency options 10,383 — 10,383 (8,806 ) — 1,577 Client interest rate derivatives 10,110 — 10,110 (10,091 ) — 19 Total derivative assets: 78,947 — 78,947 (42,356 ) (12,668 ) 23,923 Reverse repurchase, securities borrowing, and similar arrangements 64,028 — 64,028 (64,028 ) — — Total $ 142,975 $ — $ 142,975 $ (106,384 ) $ (12,668 ) $ 23,923 The following table summarizes our liabilities subject to enforceable master netting arrangements as of December 31, 2017 and 2016 : (Dollars in thousands) Gross Amounts of Recognized Liabilities Gross Amounts offset in the Statement of Financial Position Net Amounts of Liabilities Presented in the Statement of Financial Position Gross Amounts Not Offset in the Statement of Financial Position But Subject to Master Netting Arrangements Net Amount Financial Instruments Cash Collateral Pledged December 31, 2017: Derivative Liabilities: Foreign exchange forwards $ 95,454 $ — $ 95,454 $ (80,107 ) $ — $ 15,347 Foreign currency options 1,187 — 1,187 (631 ) — 556 Client interest rate derivatives 11,940 — 11,940 (11,924 ) — 16 Total derivative liabilities: 108,581 — 108,581 (92,662 ) — 15,919 Repurchase, securities lending, and similar arrangements — — — — — — Total $ 108,581 $ — $ 108,581 $ (92,662 ) $ — $ 15,919 December 31, 2016: Derivative Liabilities: Foreign exchange forwards $ 44,285 $ — $ 44,285 $ (17,964 ) $ — $ 26,321 Foreign currency options 10,383 — 10,383 (1,585 ) — 8,798 Client interest rate derivatives 9,770 — 9,770 (9,770 ) — — Total derivative liabilities: 64,438 — 64,438 (29,319 ) — 35,119 Repurchase, securities lending, and similar arrangements — — — — — — Total $ 64,438 $ — $ 64,438 $ (29,319 ) $ — $ 35,119

Noninterest Income

Noninterest Income	12 Months Ended
	Dec. 31, 2017
Other Income and Expenses [Abstract]
Noninterest Income	Noninterest Income For the year ended December 31, 2017, noninterest income was $557.2 million , compared to $456.6 million and $472.8 million , for the comparable 2016 and 2015 periods. Year ended December 31, (Dollars in thousands) 2017 2016 2015 Noninterest income: Gains on investment securities, net $ 64,603 $ 51,740 $ 89,445 Gains on equity warrant assets, net 54,555 37,892 70,963 Foreign exchange fees 115,760 104,183 87,007 Credit card fees 76,543 68,205 56,657 Deposit service charges 58,715 52,524 46,683 Client investment fees 56,136 32,219 21,610 Lending related fees 43,265 33,395 32,536 Letters of credit and standby letters of credit fees 28,544 25,644 20,889 Other 59,110 50,750 47,004 Total noninterest income $ 557,231 $ 456,552 $ 472,794 Gains on investment securities, net Net gains on investment securities include both gains and losses from our non-marketable and other securities, as well as gains and losses from sales of our AFS securities portfolio, when applicable. Our non-marketable and other securities portfolio primarily represents investments in venture capital and private equity funds, our joint venture bank in China, debt funds, private and public portfolio companies and investments in qualified affordable housing projects. Our AFS securities portfolio is primarily a fixed income investment portfolio that is managed with the objective of earning an appropriate portfolio yield over the long-term while maintaining sufficient liquidity and credit diversification as well as addressing our asset/liability management objectives. Sales of equity securities held as a result of our exercised warrants, result in net gains or losses on investment securities. A summary of gains and losses on investment securities for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Gains on non-marketable and other securities, net $ 69,792 $ 39,545 $ 88,244 (Losses) gains on sales of available-for-sale securities, net (5,189 ) 12,195 1,201 Gains on investment securities, net $ 64,603 $ 51,740 $ 89,445 Gains on equity warrant assets, net In connection with negotiating credit facilities and certain other services, we often obtain rights to acquire stock in the form of equity warrant assets in primarily private, venture-backed companies in the technology and life science/healthcare industries. Any changes in fair value from the grant date fair value of equity warrant assets will be recognized as increases or decreases to other assets on our balance sheet and as net gains or losses on equity warrant assets, in noninterest income, a component of consolidated net income. A summary of gains on equity warrant assets, net, for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Equity warrant assets: Gains on exercises, net $ 48,275 $ 31,197 $ 41,455 Cancellations and expirations (4,422 ) (3,015 ) (1,040 ) Changes in fair value, net 10,702 9,710 30,548 Net gains on equity warrant assets $ 54,555 $ 37,892 $ 70,963 Foreign exchange fees Foreign exchange fees represent the income differential between purchases and sales of foreign currency on behalf of our clients. Foreign exchange fees are recognized based on trade date and are typically settled within two business days. A summary of foreign exchange fee income by instrument type for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Foreign exchange fees by instrument type: Spot contract commissions $ 104,344 $ 89,354 $ 80,564 Forward contract commissions 10,934 14,004 6,414 Option premium fees 482 825 29 Total foreign exchange fees $ 115,760 $ 104,183 $ 87,007 Credit card fees Credit card fees include interchange income from credit and debit cards and fees earned from processing transactions for merchants. Credit card fees are earned daily upon completion of transaction settlement services. Costs related to rewards programs are recorded when the rewards are earned by the customer and presented as a reduction to interchange fee income. Annual card service fees and direct loan origination costs are deferred and recognized on a straight-line basis over a 12-month period. A summary of credit card fees by instrument type for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Credit card fees by instrument type: Card interchange fees, net $ 60,224 $ 51,513 $ 46,185 Merchant service fees 11,584 12,783 7,346 Card service fees 4,735 3,909 3,126 Total credit card fees $ 76,543 $ 68,205 $ 56,657 Deposit service charges Deposit service charges include fees earned from performing cash management activities and other deposit account services. Deposit services include, but are not limited to the following: receivables services, which include merchant services, remote capture, lockbox, electronic deposit capture, and fraud control services. Payment and cash management products and services include wire transfer and automated clearing house payment services to enable clients to transfer funds more quickly, as well as business bill pay, business credit and debit cards, account analysis, and disbursement services. Deposit service charges are recognized over the period in which the related service is provided, generally on a monthly basis. Client investment fees Client investment fees include fees earned from Rule 12(b)-1 fees, revenue sharing and from customer transactional based fees. Rule 12(b)-1 fees and revenue sharing are recognized as earned based on client funds that are invested in the period. Transactional based fees are earned and recognized on fixed income securities when the transaction is executed on the clients' behalf. Amounts paid to third-party service providers are predominantly expensed, such that client investment fees are recorded gross of payments made to third parties. A summary of client investment fees by instrument type for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Client investment fees by type: Sweep money market fees $ 28,485 $ 15,147 $ 9,347 Asset management fees 16,831 15,389 12,263 Client directed investment fees 10,820 1,683 — Total client investment fees $ 56,136 $ 32,219 $ 21,610 Lending related fees Unused commitment fees, minimum finance fees and unused line fees are recognized as earned on a monthly basis. Fees that qualify for syndication treatment are recognized at the completion of the syndicated loan deal for which the fees were received. A summary of lending related fees by instrument type for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Lending related fees by instrument type: Unused commitment fees $ 34,110 $ 25,654 $ 24,025 Other 9,155 7,741 8,511 Total lending related fees $ 43,265 $ 33,395 $ 32,536 Letters of credit and standby letters of credit fees Commercial and standby letters of credit represent conditional commitments issued by us on behalf of a client to guarantee the performance of the client to a third party when certain specified future events have occurred. Fees generated from letters of credit and standby letters of credit are deferred as a component of other liabilities and recognized in noninterest income over the commitment period using the straight-line method, based on the likelihood that the commitment being drawn down will be remote. Other noninterest income Other noninterest income primarily includes income from fund management fees, valuation service-based fee income and other service revenue. Fund management fees are comprised of fees charged directly to our managed funds of funds and direct venture funds. Fund management fees are based upon the contractual terms of the limited partnership agreements and are recognized as earned over the specified contract period, which is generally equal to the life of the individual fund. Other service revenue primarily includes revenue from dividends on FHLB/FRB stock, correspondent bank rebate income, incentive fees related to carried interest and other fee income. We recognize revenue when: (i) persuasive evidence of an arrangement exists, (ii) we have performed the service, provided we have no other remaining obligations to the customer, (iii) the fee is fixed or determinable and, (iv) collectability is probable. A summary of other noninterest income by instrument type for 2017 , 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Fund management fees $ 21,214 $ 19,195 $ 15,941 Valuation fee income 3,860 7,962 8,767 Gains on revaluation of client foreign currency instruments, net (1) 10,882 4,215 115 (Losses) gains on client foreign exchange forward contracts, net (1) (9,969 ) (5,674 ) 694 Gains (losses) on revaluation of internal foreign currency instruments, net (2) 33,161 (16,676 ) (12,735 ) (Losses) gains on internal foreign exchange forward contracts, net (2) (32,286 ) 16,136 12,377 Other service revenue 32,248 25,592 21,845 Total other noninterest income $ 59,110 $ 50,750 $ 47,004 (1) Represents the net revaluation of client foreign currency denominated financial instruments. We enter into client foreign exchange forward contracts to economically reduce our foreign exchange exposure related to client foreign currency denominated financial instruments. (2) Represents the net revaluation of foreign currency denominated financial instruments issued and held by us, primarily loans, deposits and cash. We enter into internal foreign exchange forward contracts to economically reduce our foreign exchange exposure related to these foreign currency denominated financial instruments issued and held by us.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We are subject to income tax in the U.S. federal jurisdiction and various state and foreign jurisdictions and have identified our federal and California tax returns as major tax filings. Our U.S. federal tax returns for 2014 and subsequent years remain open to full examination. Our California tax returns for 2012 and subsequent tax years remain open to full examination. The components of our provision for income taxes for 2017 , 2016 and 2015 were as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Current provision: Federal $ 263,231 $ 195,249 $ 191,194 State 67,046 59,319 50,815 Deferred expense (benefit): Federal 24,654 (3,560 ) (11,270 ) State 532 (675 ) (1,985 ) Income tax expense $ 355,463 $ 250,333 $ 228,754 Our effective tax rate is calculated by dividing income tax expense by the sum of income before income tax expense and the net income attributable to noncontrolling interests. The reconciliation between the federal statutory income tax rate and our effective income tax rate for 2017 , 2016 and 2015 , is as follows: December 31, (Dollars in thousands) 2017 2016 2015 Federal statutory income tax rate 35.0 % 35.0 % 35.0 % State income taxes, net of the federal tax effect 5.8 5.9 5.7 Net deferred tax assets revaluation (TCJ Act) 4.3 — — Meals and entertainment 0.3 0.4 0.3 Disallowed officer's compensation 0.1 0.1 0.3 Share-based compensation expense on incentive stock options and ESPP (2.1 ) — — Qualified affordable housing project tax credits (0.4 ) (0.5 ) (0.5 ) Tax-exempt interest income (0.3 ) (0.2 ) (0.2 ) Valuation allowance benefit — (0.3 ) (0.4 ) Other, net (0.7 ) (0.9 ) (0.3 ) Effective income tax rate 42.0 % 39.5 % 39.9 % Deferred tax assets and liabilities at December 31, 2017 and 2016 , consisted of the following: December 31, (Dollars in thousands) 2017 2016 Deferred tax assets: Allowance for loan losses $ 84,812 $ 110,248 Net unrealized losses on AFS debt securities 12,404 — Share-based compensation expense 9,418 15,498 State income taxes 9,186 12,682 Accrued compensation 8,336 6,799 Deferred rent 8,169 10,050 Other accruals 7,165 20,502 Net operating loss 2,300 4,116 Loan fee income and costs 1,189 8,266 Other 3,639 2,168 Deferred tax assets 146,618 190,329 Valuation allowance (2,624 ) (4,440 ) Net deferred tax assets after valuation allowance 143,994 185,889 Deferred tax liabilities: Derivative equity warrant assets (29,127 ) (36,406 ) Change in accounting method (section 481(a)) (15,953 ) (35,262 ) Net unrealized gains on AFS equity securities (11,145 ) — Non-marketable and other securities (10,724 ) (6,075 ) Premises and equipment and other intangibles (9,223 ) (11,956 ) Net unrealized gains on AFS debt securities — (17,970 ) Other (3,977 ) (6,380 ) Deferred tax liabilities (80,149 ) (114,049 ) Net deferred tax assets $ 63,845 $ 71,840 At December 31, 2017 we revalued our net deferred tax assets based on the lower corporate tax rate associated with the TCJ Act enacted into law on December 22, 2017. The TCJ Act resulted in increases to income tax expense of $33.8 million related to the revaluation of our deferred tax assets, incorporating the new federal tax rate related to the TCJ Act. At December 31, 2017 and 2016 , federal net operating loss carryforwards totaled $3 million and $4 million , respectively. Our foreign net operating loss carryforwards totaled $11 million and $16 million at December 31, 2017 and 2016, respectively. These net operating loss carryforwards expire at various dates beginning in 2022. Currently, we believe that it is more likely than not that the benefit from these net operating loss carryforwards, which are associated with our former eProsper business unit, part of SVB Analytics, and our UK operations, will not be realized in the near term due to uncertainties in the timing of future profitability in those businesses. In recognition of this, our valuation allowance is $3 million on the deferred tax assets related to these net operating loss carryforwards and research and development credits at December 31, 2017 . We believe it is more likely than not that the remaining deferred tax assets will be realized through recovery of taxes previously paid and/or future taxable income. Therefore, no valuation allowance was provided for the remaining deferred tax assets. At December 31, 2017 , our unrecognized tax benefit was $12 million , the recognition of which would reduce our income tax expense by $9 million . We do not expect that our unrecognized tax benefit will materially change in the next 12 months. We recognize interest and penalties related to income tax matters as part of income before income taxes. Interest and penalties were not material for the years ended December 31, 2017, 2016 and 2015. A summary of changes in our unrecognized tax benefit (including interest and penalties) for December 31, 2017, 2016 and 2015 is as follows: (Dollars in thousands) Reconciliation of Unrecognized Tax Benefit Interest & Penalties Total Balance at December 31, 2014 $ 3,397 $ 100 $ 3,497 Additions for tax positions for current year 1,208 — 1,208 Additions for tax positions for prior years — 228 228 Reduction for tax positions for prior years (1,228 ) (22 ) (1,250 ) Lapse of the applicable statute of limitations (20 ) (5 ) (25 ) Balance at December 31, 2015 $ 3,357 $ 301 $ 3,658 Additions for tax positions for current year 793 — 793 Additions for tax positions for prior years 1,427 166 1,593 Reduction for tax positions for prior years (271 ) (16 ) (287 ) Lapse of the applicable statute of limitations (37 ) (9 ) (46 ) Balance at December 31, 2016 $ 5,269 $ 442 $ 5,711 Additions for tax positions for current year 3,141 — 3,141 Additions for tax positions for prior years 3,378 754 4,132 Reduction for tax positions for prior years (223 ) (1 ) (224 ) Lapse of the applicable statute of limitations (60 ) (17 ) (77 ) Balance at December 31, 2017 $ 11,505 $ 1,178 $ 12,683

Other Noninterest Expense (Note

Other Noninterest Expense (Notes)	12 Months Ended
	Dec. 31, 2017
Other noninterest expense [Abstract]
Other Noninterest Expense	Other Noninterest Expense A summary of other noninterest expense for 2017 , 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Lending and other client related processing costs $ 23,768 $ 19,867 $ 15,944 Telephone 10,647 9,793 9,398 Data processing services 10,251 9,014 7,316 Dues and publications 3,263 2,828 2,476 Postage and supplies 2,797 2,851 3,154 Other 21,419 17,890 19,999 Total other noninterest expense $ 72,145 $ 62,243 $ 58,287

Employee Compensation and Benef

Employee Compensation and Benefit Plans	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Employee Compensation and Benefit Plans	Employee Compensation and Benefit Plans Our employee compensation and benefit plans include: (i) Incentive Compensation Plan; (ii) Direct Drive Incentive Compensation Plan; (iii) Retention Program; (iv) Warrant Incentive Plan; (v) Deferred Compensation Plan; (vi) 401(k) and ESOP; (vii) EHOP; (viii) 2006 Incentive Plan; and (ix) ESPP. The 2006 Incentive Plan and the ESPP are described in Note 4—“Share-Based Compensation” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report . A summary of expenses incurred under certain employee compensation and benefit plans for 2017 , 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Incentive Compensation Plan $ 125,584 $ 96,892 $ 97,565 Direct Drive Incentive Compensation Plan 18,721 21,174 21,930 Retention Program 1,317 1,475 1,996 Warrant Incentive Plan 15,386 4,954 9,110 Deferred Compensation Plan 203 1,318 2,404 SVBFG 401(k) Plan 17,860 16,078 13,809 SVBFG ESOP 4,719 3,159 8,585 Incentive Compensation Plan Our Incentive Compensation Plan (“ICP”) is an annual cash incentive plan that rewards performance based on our financial results and other performance criteria. Awards are made based on company performance, the employee's target bonus level, and management's assessment of individual employee performance. Direct Drive Incentive Compensation Plan The Direct Drive Incentive Compensation Plan (“Direct Drive”) is an annual sales cash incentive program. Awards are based on sales teams' performance as to predetermined financial targets and other company/individual performance criteria. Actual awards for each sales team member under Direct Drive are based on: (i) the actual results and financial performance with respect to the incentive gross profit targets; (ii) the sales team payout targets; and (iii) the sales team member's sales position and team payout allocation. Retention Program The Retention Program (“RP”) is a long-term incentive plan that allows designated employees to share directly in our investment success. Plan participants were granted an interest in the distributions of gains from certain designated investments made by us during the applicable year. Specifically, participants share in: (i) returns from designated investments made by us, including investments in certain venture capital and private equity funds, debt funds, and direct equity investments in companies; (ii) income realized from the exercise of, and the subsequent sale of shares obtained through the exercise of, warrants held by us; and (iii) other designated amounts as determined by us. Since 2009, no new participants have been added and no new investments have been designated to the plan. Warrant Incentive Plan The Warrant Incentive Plan provides individual and team awards to those employees who negotiate warrants on our behalf. Designated participants, as determined by the Company, share in the cash proceeds received by the Company from the exercise of equity warrant assets. Deferred Compensation Plan Under the Deferred Compensation Plan (the “DC Plan”), eligible employees may elect to defer up to 50 percent of their base salary and/or up to 100 percent of any eligible bonus payment to which they are entitled, for a period of 12 consecutive months, beginning January 1 st and ending December 31 st . Any amounts deferred under the DC Plan will be invested and administered by us (or such person we designate). We do not match employee deferrals to the DC Plan. From time to time, we may also offer deferred special retention incentives under this plan to key plan participants. The deferred incentives are eligible for investment in the DC Plan during the retention qualifying period. Voluntary deferrals under the DC Plan were $5.5 million , $4.4 million and $3.7 million in 2017 , 2016 and 2015 , respectively. The DC Plan overall, had investment gains of $4.7 million and $2.4 million in 2017 and 2016, respectively, and losses of $0.1 million in 2015 . 401(k) and ESOP The 401(k) Plan and ESOP, collectively referred to as the “Plan”, is a combined 401(k) tax-deferred savings plan and employee stock ownership plan in which all regular U.S. employees are eligible to participate. Employees participating in the 401(k) Plan are allowed to contribute up to 75 percent of their pre-tax pay as defined in the Plan, up to the maximum annual amount allowable under federal income tax regulations of $18,000 for the years 2017, 2016 and 2015. We match the employee's contributions dollar-for-dollar, up to five percent of the employee's pre-tax pay as defined in the Plan. Our matching contributions vest immediately. The amount of salary deferred, up to the allowed maximum, is not subject to federal or state income taxes at the time of deferral. Discretionary ESOP contributions, based on our company performance, are made by us to all eligible individuals employed by us on the last day of the fiscal year. We may elect to contribute cash or our common stock (or a combination of cash and stock), in an amount not exceeding ten percent of the employee's eligible pay earned in the fiscal year. The ESOP contributions vest in equal annual increments over a participant's first five years of service (thereafter, all subsequent ESOP contributions are fully vested). EHOP The EHOP is a benefit plan that provides for the issuance of mortgage loans at favorable interest rates to eligible employees. Eligible employees may apply for a fixed-rate mortgage for their primary residence, which is due and payable in either five or seven years and is based on amortization over a 30 year period. Applicants must qualify for a loan through the normal mortgage review and approval process, which is typical of industry standards. The maximum loan amount generally cannot be greater than 80 percent of the lesser of the purchase price or the appraised value. The interest rate on the loan is written at the then market rate for five year (5/1) or seven year (7/1) mortgage loans as determined by us. However, provided that the applicant continues to meet all the eligibility requirements, including employment, the actual rate charged to the borrower shall be up to two percent below the market rate. The loan rate shall not be less than the greater of either the jumbo conforming market rate (corresponding to the maturity of the loan) or the monthly Applicable Federal Rate for medium-term loans as published by the Internal Revenue Service. The loan rate will be fixed at the time of approval and locked in for 30 days. For additional details, see Note 9—“Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report .

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Parties	Related Parties We have no material related party transactions requiring disclosure. In the ordinary course of business, the Bank may extend credit to related parties, including executive officers, directors, principal shareholders and their related interests. Additionally, we also provide real estate secured loans to eligible employees through our EHOP. For additional details, see Note 17—“Employee Compensation and Benefit Plans” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report .

Off-Balance Sheet Arrangements,

Off-Balance Sheet Arrangements, Guarantees and Other Commitments	12 Months Ended
	Dec. 31, 2017
Disclosure Off Balance Sheet Arrangements Guarantees And Other Commitments Additional Information [Abstract]
Off-Balance Sheet Arrangements, Guarantees and Other Commitments	Off-Balance Sheet Arrangements, Guarantees and Other Commitments Operating Leases We are obligated under a number of noncancelable operating leases for premises and equipment that expire at various dates, through 2030, and in most instances, include options to renew or extend at market rates and terms. Such leases may provide for periodic adjustments of rentals during the term of the lease based on changes in various economic indicators. The following table presents minimum future payments under noncancelable operating leases as of December 31, 2017 : Year ended December 31, (Dollars in thousands) Amount 2018 $ 35,627 2019 35,545 2020 32,117 2021 31,451 2022 27,501 2023 and thereafter 64,234 Net minimum operating lease payments $ 226,475 Rent expense for premises and equipment leased under operating leases totaled $31.3 million , $24.8 million and $21.9 million in 2017 , 2016 and 2015 , respectively. Commitments to Extend Credit A commitment to extend credit is a formal agreement to lend funds to a client as long as there is no violation of any condition established in the agreement. Such commitments generally have fixed expiration dates, or other termination clauses, and usually require a fee paid by the client upon us issuing the commitment. The following table summarizes information related to our commitments to extend credit at December 31, 2017 and 2016 , respectively: December 31, (Dollars in thousands) 2017 2016 Loan commitments available for funding: (1) Fixed interest rate commitments $ 1,478,157 $ 1,475,179 Variable interest rate commitments 14,034,169 13,572,161 Total loan commitments available for funding 15,512,326 15,047,340 Commercial and standby letters of credit (2) 1,950,211 1,695,856 Total unfunded credit commitments $ 17,462,537 $ 16,743,196 Commitments unavailable for funding (3) $ 2,117,057 $ 1,719,524 Allowance for unfunded credit commitments (4) 51,770 45,265 (1) Represents commitments which are available for funding, due to clients meeting all collateral, compliance and financial covenants required under loan commitment agreements. (2) See below for additional information on our commercial and standby letters of credit. (3) Represents commitments which are currently unavailable for funding due to clients failing to meet all collateral, compliance and financial covenants under loan commitment agreements. (4) Our allowance for unfunded credit commitments includes an allowance for both our unfunded loan commitments and our letters of credit. Our potential exposure to credit loss for commitments to extend credit, in the event of nonperformance by the other party to the financial instrument, is the contractual amount of the available unused loan commitment. We use the same credit approval and monitoring process in extending credit commitments as we do in making loans. The actual liquidity needs and the credit risk that we have experienced have historically been lower than the contractual amount of commitments to extend credit because a significant portion of these commitments expire without being drawn upon. We evaluate each potential borrower and the necessary collateral on an individual basis. The type of collateral varies, but may include real property, intellectual property, bank deposits, or business and personal assets. The credit risk associated with these commitments is considered in the allowance for unfunded credit commitments. Commercial and Standby Letters of Credit Commercial and standby letters of credit represent conditional commitments issued by us on behalf of a client to guarantee the performance of the client to a third party when certain specified future events have occurred. Commercial letters of credit are issued primarily for inventory purchases by a client and are typically short-term in nature. We provide two types of standby letters of credit: performance and financial standby letters of credit. Performance standby letters of credit are issued to guarantee the performance of a client to a third party when certain specified future events have occurred and are primarily used to support performance instruments such as bid bonds, performance bonds, lease obligations, repayment of loans, and past due notices. Financial standby letters of credit are conditional commitments issued by us to guarantee the payment by a client to a third party (beneficiary) and are primarily used to support many types of domestic and international payments. These standby letters of credit have fixed expiration dates and generally require a fee to be paid by the client at the time we issue the commitment. The credit risk involved in issuing letters of credit is essentially the same as that involved with extending credit commitments to clients, and accordingly, we use a credit evaluation process and collateral requirements similar to those for credit commitments. Our standby letters of credit often are cash secured by our clients. The actual liquidity needs and the credit risk that we have experienced historically have been lower than the contractual amount of letters of credit issued because a significant portion of these conditional commitments expire without being drawn upon. The table below summarizes our commercial and standby letters of credit at December 31, 2017 . The maximum potential amount of future payments represents the amount that could be remitted under letters of credit if there were a total default by the guaranteed parties, without consideration of possible recoveries under recourse provisions or from the collateral held or pledged. (Dollars in thousands) Expires In One Year or Less Expires After One Year Total Amount Outstanding Maximum Amount of Future Payments Financial standby letters of credit $ 1,765,857 $ 60,819 $ 1,826,676 $ 1,826,676 Performance standby letters of credit 94,519 11,105 105,624 105,624 Commercial letters of credit 17,911 — 17,911 17,911 Total $ 1,878,287 $ 71,924 $ 1,950,211 $ 1,950,211 Deferred fees related to financial and performance standby letters of credit were $12 million at December 31, 2017 and $10 million at December 31, 2016 . At December 31, 2017 , collateral in the form of cash of $961 million was available to us to reimburse losses, if any, under financial and performance standby letters of credit. Commitments to Invest in Venture Capital and Private Equity Funds We make commitments to invest in venture capital and private equity funds, which generally makes investments in privately-held companies. Commitments to invest in these funds are generally made for a 10 -year period from the inception of the fund. Although the limited partnership agreements governing these investments typically do not restrict the general partners from calling 100% of committed capital in one year, it is customary for these funds to call most of the capital commitments over 5 to 7 years, and in certain cases, the funds may not call 100% of committed capital. The actual timing of future cash requirements to fund these commitments is generally dependent upon the investment cycle, overall market conditions, and the nature and type of industry in which the privately held companies operate. The following table details our total capital commitments, unfunded capital commitments, and our ownership percentage in each fund at December 31, 2017 : (Dollars in thousands) SVBFG Capital Commitments SVBFG Unfunded Commitments SVBFG Ownership of each Fund (3) CP I, LP $ 6,000 $ 270 10.7 % CP II, LP (1) 1,200 162 5.1 Shanghai Yangpu Venture Capital Fund (LP) 891 — 6.8 Strategic Investors Fund, LP 15,300 688 12.6 Strategic Investors Fund II, LP 15,000 1,050 8.6 Strategic Investors Fund III, LP 15,000 1,275 5.9 Strategic Investors Fund IV, LP 12,239 2,325 5.0 Strategic Investors Fund V funds 515 131 Various Capital Preferred Return Fund, LP 12,688 — 20.0 Growth Partners, LP 24,670 1,340 33.0 Debt funds (equity method accounting) 58,493 — Various Other fund investments (2) 302,659 8,901 Various Total $ 464,655 $ 16,142 (1) Our ownership includes direct ownership of 1.3 percent and indirect ownership of 3.8 percent through our investment in Strategic Investors Fund II, LP. (2) Represents commitments to 241 funds (primarily venture capital funds) where our ownership interest is generally less than five percent of the voting interests of each such fund. (3) We are subject to the Volcker Rule which restricts or limits us from sponsoring or having ownership interests in “covered” funds including venture capital and private equity funds. See “Business - Supervision and Regulation” under Part I, Item 1 of this report. The following table details the amounts of remaining unfunded commitments to venture capital and private equity funds by our consolidated managed funds of funds (including our interest and the noncontrolling interests) at December 31, 2017 : (Dollars in thousands) Unfunded Commitments Strategic Investors Fund, LP $ 1,338 Capital Preferred Return Fund, LP 1,952 Growth Partners, LP 2,552 Total $ 5,842

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair Value Measurements Our available-for-sale securities, derivative instruments and certain non-marketable and other securities are financial instruments recorded at fair value on a recurring basis. We make estimates regarding valuation of assets and liabilities measured at fair value in preparing our consolidated financial statements. We disclose our method and approach for fair value measurements of assets and liabilities in Note 2—“Summary of Significant Accounting Policies” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report . The following fair value hierarchy table presents information about our assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2017 : (Dollars in thousands) Level 1 Level 2 Level 3 Balance at December 31, 2017 Assets Available-for-sale securities: U.S. Treasury securities $ 6,840,502 $ — $ — $ 6,840,502 U.S. agency debentures — 1,567,128 — 1,567,128 Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations - fixed rate — 2,267,035 — 2,267,035 Agency-issued collateralized mortgage obligations - variable rate — 373,730 — 373,730 Equity securities 158 72,111 — 72,269 Total available-for-sale securities 6,840,660 4,280,004 — 11,120,664 Non-marketable and other securities (fair value accounting): Non-marketable securities: Venture capital and private equity fund investments measured at net asset value — — — 127,192 Other venture capital investments (1) — — 919 919 Other securities (1) 310 — — 310 Total non-marketable and other securities (fair value accounting) 310 — 919 128,421 Other assets: Foreign exchange forward and option contracts — 96,636 — 96,636 Equity warrant assets — 2,432 121,331 123,763 Client interest rate derivatives — 11,753 — 11,753 Total assets $ 6,840,970 $ 4,390,825 $ 122,250 $ 11,481,237 Liabilities Foreign exchange forward and option contracts $ — $ 96,641 $ — $ 96,641 Client interest rate derivatives — 11,940 — 11,940 Total liabilities $ — $ 108,581 $ — $ 108,581 (1) Included in Level 1 and Level 3 assets are $0.2 million and $0.8 million , respectively, attributable to noncontrolling interests calculated based on the ownership percentages of the noncontrolling interests. The following fair value hierarchy table presents information about our assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2016 : (Dollars in thousands) Level 1 Level 2 Level 3 Balance at December 31, 2016 Assets Available-for-sale securities: U.S. Treasury securities $ 8,909,491 $ — $ — $ 8,909,491 U.S. agency debentures — 2,078,375 — 2,078,375 Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations - fixed rate — 1,152,665 — 1,152,665 Agency-issued collateralized mortgage obligations - variable rate — 474,283 — 474,283 Equity securities 175 5,422 — 5,597 Total available-for-sale securities 8,909,666 3,710,745 — 12,620,411 Non-marketable and other securities (fair value accounting): Non-marketable securities: Venture capital and private equity fund investments measured at net asset value — — — 141,649 Other venture capital investments (1) — — 2,040 2,040 Other securities (1) 753 — — 753 Total non-marketable and other securities (fair value accounting) 753 — 2,040 144,442 Other assets: Interest rate swaps — 810 — 810 Foreign exchange forward and option contracts — 68,027 — 68,027 Equity warrant assets — 2,310 128,813 131,123 Client interest rate derivatives — 10,110 — 10,110 Total assets $ 8,910,419 $ 3,792,002 $ 130,853 $ 12,974,923 Liabilities Foreign exchange forward and option contracts $ — $ 54,668 $ — $ 54,668 Client interest rate derivatives — 9,770 — 9,770 Total liabilities $ — $ 64,438 $ — $ 64,438 (1) Included in Level 1 and Level 3 assets are $0.6 million and $1.8 million , respectively, attributable to noncontrolling interests calculated based on the ownership percentages of the noncontrolling interests. The following table presents additional information about Level 3 assets measured at fair value on a recurring basis for 2017 , 2016 and 2015 , respectively: (Dollars in thousands) Beginning Balance Total Realized and Unrealized Gains (Losses), net Included in Income Sales Issuances Distributions and Other Settlements Transfers Out of Level 3 Ending Balance Year ended December 31, 2017: Non-marketable and other securities (fair value accounting): Other venture capital investments (1) $ 2,040 $ 971 $ (2,092 ) $ — $ — $ — $ 919 Other assets: Equity warrant assets (2) 128,813 54,263 (74,769 ) 14,537 — (1,513 ) 121,331 Total assets $ 130,853 $ 55,234 $ (76,861 ) $ 14,537 $ — $ (1,513 ) $ 122,250 Year ended December 31, 2016: Non-marketable and other securities (fair value accounting): Other venture capital investments (1) $ 2,040 $ (21 ) $ (4 ) $ — $ 25 $ — $ 2,040 Other assets: Equity warrant assets (2) 135,168 38,091 (56,643 ) 13,405 — (1,208 ) 128,813 Total assets $ 137,208 $ 38,070 $ (56,647 ) $ 13,405 $ 25 $ (1,208 ) $ 130,853 Year ended December 31, 2015: Non-marketable and other securities (fair value accounting): Other venture capital investments $ 3,291 $ 1,192 $ (2,356 ) $ — $ (87 ) $ — $ 2,040 Other assets: Equity warrant assets (2) 114,698 71,402 (61,044 ) 12,534 — (2,422 ) 135,168 Total assets $ 117,989 $ 72,594 $ (63,400 ) $ 12,534 $ (87 ) $ (2,422 ) $ 137,208 (1) Realized and unrealized gains (losses) are recorded in the line item “Gains on investment securities, net”, a component of noninterest income. (2) Realized and unrealized gains (losses) are recorded in the line item “Gains on equity warrant assets, net”, a component of noninterest income. The following table presents the amount of unrealized gains (losses) included in earnings (which is inclusive of noncontrolling interest) attributable to Level 3 assets still held at December 31, 2017 and 2016 , respectively: Year ended December 31, (Dollars in thousands) 2017 2016 Non-marketable and other securities (fair value accounting): Other venture capital investments (1) $ (444 ) $ 1,739 Other assets: Equity warrant assets (2) 11,174 14,502 Total unrealized gains, net $ 10,730 $ 16,241 Unrealized (losses) gains attributable to noncontrolling interests $ (397 ) $ 1,553 (1) Unrealized gains are recorded on the line item “gains on investment securities, net”, a component of noninterest income. (2) Unrealized gains are recorded on the line item “gains on equity warrant assets, net”, a component of noninterest income. The extent to which any unrealized gains or losses will become realized is subject to a variety of factors, including, among other things, the expiration of current sales restrictions to which these securities are subject, the actual sales of securities and the timing of such actual sales. The following table presents quantitative information about the significant unobservable inputs used for certain of our Level 3 fair value measurements at December 31, 2017 and 2016 . We have not included in this table our venture capital and private equity fund investments (fair value accounting) as we use net asset value per share (as obtained from the general partners of the investments) as a practical expedient to determine fair value. (Dollars in thousands) Fair Value Valuation Technique Significant Unobservable Inputs Weighted Average December 31, 2017: Other venture capital investments (fair value accounting) $ 919 Private company equity pricing (1) (1) Equity warrant assets (public portfolio) 1,936 Black-Scholes option pricing model Volatility 47.9 % Risk-Free interest rate 2.1 Sales restrictions discount (2) 15.5 Equity warrant assets (private portfolio) 119,395 Black-Scholes option pricing model Volatility 36.7 Risk-Free interest rate 1.8 Marketability discount (3) 16.4 Remaining life assumption (4) 45.0 December 31, 2016: Other venture capital investments (fair value accounting) $ 2,040 Private company equity pricing (1) (1) Equity warrant assets (public portfolio) 764 Black-Scholes option pricing model Volatility 46.6 % Risk-Free interest rate 2.1 Sales restrictions discount (2) 17.7 Equity warrant assets (private portfolio) 128,049 Black-Scholes option pricing model Volatility 36.9 Risk-Free interest rate 1.3 Marketability discount (3) 17.1 Remaining life assumption (4) 45.0 (1) In determining the fair value of our other venture capital investment portfolio, we evaluate a variety of factors related to each underlying private portfolio company including, but not limited to, actual and forecasted results, cash position, recent or planned transactions and market comparable companies. Additionally, we have ongoing communication with the portfolio companies and venture capital fund managers, to determine whether there is a material change in fair value. We use company provided valuation reports, if available, to support our valuation assumptions. These factors are specific to each portfolio company and a weighted average or range of values of the unobservable inputs is not meaningful. (2) We adjust quoted market prices of public companies which are subject to certain sales restrictions. Sales restriction discounts generally range from 10 percent to 20 percent depending on the duration of the sales restrictions which typically range from three to six months. (3) Our marketability discount is applied to all private company warrants to account for a general lack of liquidity due to the private nature of the associated underlying company. The quantitative measure used is based on long-run averages and is influenced over time by various factors, including market conditions. On a quarterly basis, a sensitivity analysis is performed on our marketability discount. (4) We adjust the contractual remaining term of private company warrants based on our best estimate of the actual remaining life, which we determine by utilizing historical data on cancellations and exercises. At December 31, 2017 , the weighted average contractual remaining term was 6.0 years, compared to our estimated remaining life of 2.7 years. On a quarterly basis, a sensitivity analysis is performed on our remaining life assumption. During 2017 , 2016 and 2015 there were no transfers between Level 2 and Level 1. During 2017, 2016 and 2015, there were no transfers in our other venture capital investments from Level 3 to Level 2. All other transfers from Level 3 to Level 2 during 2017 , 2016 and 2015 were due to the transfer of equity warrant assets from our private portfolio to our public portfolio (see our Level 3 reconciliation above). All amounts reported as transfers represent the fair value as of the date of the change in circumstances that caused the transfer. Financial Instruments not Carried at Fair Value FASB guidance over financial instruments requires that we disclose estimated fair values for our financial instruments not carried at fair value. Fair value estimates, methods and assumptions, set forth below for our financial instruments, are made solely to comply with these requirements. Fair values are based on estimates or calculations at the transaction level using present value techniques in instances where quoted market prices are not available. As broadly traded markets do not exist for many of our financial instruments, the fair value calculations attempt to incorporate the effect of current market conditions at a specific time. The aggregation of the fair value calculations presented herein does not represent, and should not be construed to represent, the underlying value of the Company. The following describes the methods and assumptions used in estimating the fair values of financial instruments for which carrying value approximates fair value and assets and liabilities measured at fair value on a nonrecurring basis and excludes financial instruments and assets and liabilities already recorded at fair value as described above. Financial Instruments for which Carrying Value Approximates Fair Value Certain financial instruments that are not carried at fair value on the Consolidated Balance Sheets are carried at amounts that approximate fair value, due to their short-term nature and generally negligible credit risk. These instruments include cash and cash equivalents; FHLB and FRB stock; accrued interest receivable; short-term borrowings; short-term time deposits; and accrued interest payable. In addition, U.S. GAAP requires that the fair value of deposit liabilities with no stated maturity (i.e., demand, savings and certain money market deposits) be equal to their carrying value; recognition of the inherent funding value of these instruments is not permitted. Estimated Fair Values of Financial Instruments Not Recorded at Fair Value on a Recurring Basis Held-to-Maturity Securities Held-to-maturity securities include similar investments held in our AFS securities portfolio and are valued using the same methodologies. All securities included in our HTM securities portfolio are valued using Level 2 inputs. Refer to Level 2 fair value measurements in Note 2—“Summary of Significant Accounting Policies” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report for significant inputs used in the valuation of our HTM securities. Non-Marketable (Cost and Equity Method Accounting) Non-marketable securities includes other investments (equity method accounting), venture capital and private equity fund investments (cost method accounting) and other venture capital investments (cost method accounting). Other investments (equity method accounting) includes our investment in SPD-SVB, our joint venture bank in China. At this time, the carrying value of our investment in SPD-SVB is a reasonable estimate of fair value. The fair value of the remaining other investments (equity method accounting) and the fair value of venture capital and private equity fund investments (cost method accounting) and other venture capital investments (cost method accounting) is based on financial information obtained from the fund investments’ or debt fund investments’ respective general partners. For private company investments, estimated fair value is based on consideration of a range of factors including, but not limited to, the price at which the investment was acquired, the term and nature of the investment, local market conditions, values for comparable securities, current and projected operating performance, exit strategies, and financing transactions subsequent to the acquisition of the investment. For our fund investments, we utilize the net asset value per share as obtained from the general partners of the investments. We adjust the net asset value per share for differences between our measurement date and the date of the fund investment’s net asset value by using the most recently available financial information from the investee general partner, for example September 30 th , for our December 31 st consolidated financial statements, adjusted for any contributions paid, distributions received from the investment, and significant fund transactions or market events during the reporting period. Loans The fair value of fixed and variable rate loans is estimated by discounting contractual cash flows using rates that reflect current pricing for similar loans and the projected forward yield curve. This method is not based on the exit price concept of fair value required under ASC 820, Fair Value Measurements and Disclosures . Long-Term Deposits The fair value of long-term time deposits is estimated by discounting the cash flows using our cost of borrowings and the projected forward yield curve over their remaining contractual term. Long-Term Debt The fair value of long-term debt is generally based on quoted market prices, when available, or is estimated based on calculations utilizing third party pricing services and current market spread, price indications from reputable dealers or observable market prices of the underlying instrument(s), whichever is deemed more reliable. Off-Balance Sheet Financial Instruments The fair value of net available commitments to extend credit is estimated based on the average amount we would receive or pay to execute a new agreement with identical terms and pricing, while taking into account the counterparties’ credit standings. Letters of credit are carried at their fair value, which is equivalent to the residual premium or fee at December 31, 2017 and 2016 . Commitments to extend credit and letters of credit typically result in loans with a market interest rate if funded. The following fair value hierarchy table presents the estimated fair values of our financial instruments that are not carried at fair value at December 31, 2017 and 2016 : Estimated Fair Value (Dollars in thousands) Carrying Amount Total Level 1 Level 2 Level 3 December 31, 2017: Financial assets: Cash and cash equivalents $ 2,923,075 $ 2,923,075 $ 2,923,075 $ — $ — Held-to-maturity securities 12,663,455 12,548,280 — 12,548,280 — Non-marketable securities (cost and equity method accounting) not measured at net asset value 120,019 126,345 — — 126,345 Non-marketable securities (cost and equity method accounting) measured at net asset value (1) 228,399 331,496 — — — Net commercial loans 20,238,247 20,520,623 — — 20,520,623 Net consumer loans 2,613,045 2,593,538 — — 2,593,538 FHLB and FRB stock 60,020 60,020 — — 60,020 Accrued interest receivable 141,773 141,773 — 141,773 — Financial liabilities: Short-term FHLB advances 700,000 700,000 700,000 — — Federal funds purchased 330,000 330,000 330,000 — — Other short-term borrowings 3,730 3,730 3,730 — — Non-maturity deposits (2) 44,206,929 44,206,929 44,206,929 — — Time deposits 47,146 46,885 — 46,885 — 3.50% Senior Notes 347,303 352,058 — 352,058 — 5.375% Senior Notes 348,189 374,483 — 374,483 — Accrued interest payable 11,192 11,192 — 11,192 — Off-balance sheet financial assets: Commitments to extend credit — 22,208 — — 22,208 December 31, 2016: Financial assets: Cash and cash equivalents $ 2,545,750 $ 2,545,750 $ 2,545,750 $ — $ — Held-to-maturity securities 8,426,998 8,376,138 — 8,376,138 — Non-marketable securities (cost and equity method accounting) not measured at net asset value 120,037 127,343 — — 127,343 Non-marketable securities (cost and equity method accounting) measured at net asset value (1) 245,626 353,870 — — — Net commercial loans 17,518,430 17,811,356 — — 17,811,356 Net consumer loans 2,156,148 2,199,501 — — 2,199,501 FHLB and FRB stock 57,592 57,592 — — 57,592 Accrued interest receivable 111,222 111,222 — 111,222 — Financial liabilities: Short-term FHLB advances 500,000 500,000 500,000 — — Other short-term borrowings 12,668 12,668 12,668 — — Non-maturity deposits (2) 38,923,750 38,923,750 38,923,750 — — Time deposits 56,118 55,949 — 55,949 — 3.50% Senior Notes 346,979 337,600 — 337,600 — 5.375% Senior Notes 347,586 378,777 — 378,777 — 6.05% Subordinated Notes (3) 46,646 47,489 — 47,489 — 7.0% Junior Subordinated Debentures 54,493 53,140 — 53,140 — Accrued interest payable 12,013 12,013 — 12,013 — Off-balance sheet financial assets: Commitments to extend credit — 22,074 — — 22,074 (1) In accordance with the accounting standard (ASU 2015-07, Fair Value Measurement (Topic 820)), certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. (2) Includes noninterest-bearing demand deposits, interest-bearing checking accounts, money market accounts and interest-bearing sweep deposits. (3) At December 31, 2016 , included in the carrying value and estimated fair value of our 6.05% Subordinated Notes was $0.8 million related to hedge accounting associated with the notes. Investments in Entities that Calculate Net Asset Value Per Share FASB guidance over certain fund investments requires that we disclose the fair value of funds, significant investment strategies of the investees, redemption features of the investees, restrictions on the ability to sell investments, estimate of the period of time over which the underlying assets are expected to be liquidated by the investee, and unfunded commitments related to the investments. Our investments in debt funds and venture capital and private equity fund investments generally cannot be redeemed. Alternatively, we expect distributions, if any, to be received primarily through IPOs and M&A activity of the underlying assets of the fund. Subject to applicable requirements under the Volcker Rule, we do not have any plans to sell any of these fund investments. If we decide to sell these investments in the future, the investee fund’s management must approve of the buyer before the sale of the investments can be completed. The fair values of the fund investments have been estimated using the net asset value per share of the investments, adjusted for any differences between our measurement date and the date of the fund investment’s net asset value by using the most recently available financial information from the investee general partner, for example September 30 th , for our December 31 st consolidated financial statements, adjusted for any contributions paid, distributions received from the investment, and significant fund transactions or market events during the reporting period. The following table is a summary of the estimated fair values of these investments and remaining unfunded commitments for each major category of these investments as of December 31, 2017 : (Dollars in thousands) Carrying Amount Fair Value Unfunded Commitments Non-marketable securities (fair value accounting): Venture capital and private equity fund investments (1) $ 127,192 $ 127,192 $ 5,842 Non-marketable securities (equity method accounting): Venture capital and private equity fund investments (2) 89,809 89,809 4,943 Debt funds (2) 21,183 21,183 — Other investments (2) 18,859 18,859 886 Non-marketable securities (cost method accounting): Venture capital and private equity fund investments (2) 98,548 201,645 8,015 Total $ 355,591 $ 458,688 $ 19,686 (1) Venture capital and private equity fund investments within non-marketable securities (fair value accounting) include investments made by our managed funds of funds and one of our direct venture funds. These investments represent investments in venture capital and private equity funds that invest primarily in U.S. and global technology and life science/healthcare companies. Included in the fair value and unfunded commitments of fund investments under fair value accounting are $94.2 million and $4.4 million , respectively, attributable to noncontrolling interests. It is estimated that we will receive distributions from the fund investments over the next 10 to 13 years, depending on the age of the funds and any potential extensions of terms of the funds. (2) Venture capital and private equity fund investments, debt funds, and other fund investments within non-marketable securities (equity and cost method accounting) include funds that invest in or lend money to primarily U.S. and global technology and life science/healthcare companies. It is estimated that we will receive distributions from the funds over the next 10 to 13 years, depending on the age of the funds and any potential extensions of the terms of the funds.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Regulatory Matters	Regulatory Matters SVB Financial and the Bank are subject to various regulatory capital adequacy requirements administered by the Federal Reserve Board and the California Department of Business Oversight - Division of Financial Institutions. The Federal Deposit Insurance Corporation Improvement Act of 1991 (“FDICIA”) required that the federal regulatory agencies adopt regulations defining five capital categories for banks: well capitalized, adequately capitalized, undercapitalized, significantly undercapitalized and critically undercapitalized. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on our consolidated financial statements. Quantitative measures, established by the regulators to ensure capital adequacy, require that SVB Financial and the Bank maintain minimum ratios (set forth in the table below) of capital to risk-weighted assets. Effective January 1, 2015, SVB Financial Group and the Bank became subject to a regulatory capital measure called "Common Equity Tier 1" and a related regulatory capital ratio of CET 1 to risk-weighted assets implemented under "Basel III" regulatory capital reforms and changes required by the Dodd-Frank Act. There are three categories of capital under the new Basel III standards; CET 1, additional Tier 1 and Tier 2. CET 1 includes common stock plus related surplus and retained earnings, less certain deductions. Additional Tier 1 capital includes qualifying preferred stock and trust preferred securities, less certain deductions. Additional Tier 1, together with CET 1, equal total Tier 1 capital. Tier 2 capital includes primarily certain qualifying unsecured subordinated debt and qualifying allowances for loan and lease losses. Tier 1 capital together with Tier 2 capital equal total capital. As of December 31, 2017 , both SVB Financial and the Bank were considered “well-capitalized” for regulatory purposes under existing capital guidelines. There are no conditions or events since that date that management believes would have a material impact on that capital category. The following table presents the capital ratios for the Company and the Bank under federal regulatory guidelines, compared to the minimum regulatory capital requirements for an adequately capitalized and a well-capitalized depository institution, as of December 31, 2017 and 2016 : Capital Ratios Capital Amounts (Dollars in thousands) Actual Well Capitalized Minimum Adequately Capitalized Minimum Actual Well Capitalized Minimum Adequately Capitalized Minimum December 31, 2017: CET 1 risk-based capital: SVB Financial 12.78 % 6.5 % 4.5 % $ 4,182,315 $ 2,127,902 $ 1,473,163 Bank 12.06 6.5 4.5 3,787,988 2,041,227 1,413,157 Tier 1 risk-based capital: SVB Financial 12.97 8.0 6.0 4,246,606 2,618,957 1,964,218 Bank 12.06 8.0 6.0 3,787,988 2,512,279 1,884,209 Total risk-based capital: SVB Financial 13.96 10.0 8.0 4,571,542 3,273,696 2,618,957 Bank 13.04 10.0 8.0 4,094,782 3,140,349 2,512,279 Tier 1 leverage: SVB Financial 8.34 N/A 4.0 4,246,606 N/A 2,036,138 Bank 7.56 5.0 4.0 3,787,988 2,504,636 2,003,709 December 31, 2016: CET 1 risk-based capital: SVB Financial 12.80 % 6.5 % 4.5 % $ 3,616,404 $ 1,836,169 $ 1,271,194 Bank 12.65 6.5 4.5 3,397,232 1,745,695 1,208,558 Tier 1 risk-based capital: SVB Financial 13.26 8.0 6.0 3,744,605 2,259,900 1,694,925 Bank 12.65 8.0 6.0 3,397,232 2,148,548 1,611,411 Total risk-based capital: SVB Financial 14.21 10.0 8.0 4,015,236 2,824,875 2,259,900 Bank 13.66 10.0 8.0 3,667,709 2,685,685 2,148,548 Tier 1 leverage: SVB Financial 8.34 N/A 4.0 3,744,605 N/A 1,796,387 Bank 7.67 5.0 4.0 3,397,232 2,214,467 1,771,574

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting We have three reportable segments for management reporting purposes: Global Commercial Bank, SVB Private Bank and SVB Capital. The results of our operating segments are based on our internal management reporting process. Our Global Commercial Bank and SVB Private Bank segments’ primary source of revenue is from net interest income, which is primarily the difference between interest earned on loans, net of funds transfer pricing ( " FTP " ) and interest paid on deposits, net of FTP. Accordingly, these segments are reported using net interest income, net of FTP. FTP is an internal measurement framework designed to assess the financial impact of a financial institution’s sources and uses of funds. It is the mechanism by which an earnings credit is given for deposits raised, and an earnings charge is made for funded loans. FTP is calculated at an instrument level based on account characteristics. We also evaluate performance based on provision for credit losses, noninterest income and noninterest expense, which are presented as components of segment operating profit or loss. In calculating each operating segment’s noninterest expense, we consider the direct costs incurred by the operating segment as well as certain allocated direct costs. As part of this review, we allocate certain corporate overhead costs to a corporate account. We do not allocate income taxes or the provision for unfunded credit commitments (included in provision for credit losses) to our segments. Additionally, our management reporting model is predicated on average asset balances; therefore, period-end asset balances are not presented for segment reporting purposes. Changes in an individual client’s primary relationship designation have resulted, and in the future may result, in the inclusion of certain clients in different segments in different periods. Unlike financial reporting, which benefits from the comprehensive structure provided by GAAP, our internal management reporting process is highly subjective, as there is no comprehensive, authoritative guidance for management reporting. Our management reporting process measures the performance of our operating segments based on our internal operating structure, which is subject to change from time to time, and is not necessarily comparable with similar information for other financial services companies. For reporting purposes, SVB Financial Group has three operating segments for which we report our financial information (for further description of these reportable segments, refer to "Business–Business Overview" under Part I, Item 1 of this report): • Global Commercial Bank is comprised of results from the following: ◦ Our Commercial Bank products and services are provided by the Bank and its subsidiaries to commercial clients primarily in the technology, life science/healthcare, and private equity/venture capital industries. The Bank provides solutions to the financial needs of commercial clients through credit, treasury management, foreign exchange, trade finance, and other services. We broadly serve clients within the U.S., as well as non-U.S. clients in key international innovation markets. In addition, the Bank and its subsidiaries offer a variety of investment services and solutions to its clients that enable them to effectively manage their assets. ◦ Our Private Equity Division provides banking products and services primarily to our private equity and venture capital clients. ◦ SVB Wine provides banking products and services to our premium wine industry clients, including vineyard development loans. ◦ SVB Analytics previously provided equity valuation services to companies and private equity/venture capital firms and currently provides research for investors and companies in the global innovation economy. In September 2017, SVB Analytics sold its equity valuation services business. ◦ Debt Fund Investments is comprised of our investments in certain debt funds in which we are a strategic investor. • SVB Private Bank is the private banking division of the Bank, which provides a range of personal financial solutions for consumers. Our clients are primarily private equity/venture capital professionals and executive leaders of the innovation companies they support. We offer a customized suite of private banking services, including mortgages, home equity lines of credit, restricted stock purchase loans, capital call lines of credit and other secured and unsecured lending products, as well as cash and wealth management services. • SVB Capital is the funds management business of SVBFG, which focuses primarily on venture capital investments. SVB Capital manages funds (primarily venture capital funds) on behalf of third party limited partners and, on a more limited basis, SVB Financial Group. The SVB Capital family of funds is comprised of direct venture funds that invest in companies and funds of funds that invest in other venture capital funds. SVB Capital generates income for the Company primarily from investment returns (including carried interest allocations) and management fees. The summary financial results of our operating segments are presented along with a reconciliation to our consolidated results. Our segment information for 2017 , 2016 and 2015 is as follows: (Dollars in thousands) Global Commercial Bank (1) SVB Private Bank SVB Capital (1) Other Items (2) Total Year ended December 31, 2017 Net interest income $ 1,274,366 $ 58,131 $ 48 $ 87,824 $ 1,420,369 Provision for credit losses (81,553 ) (4,386 ) — (6,365 ) (92,304 ) Noninterest income 366,000 2,175 58,992 130,064 557,231 Noninterest expense (3) (706,341 ) (17,693 ) (19,340 ) (267,281 ) (1,010,655 ) Income before income tax expense (4) $ 852,472 $ 38,227 $ 39,700 $ (55,758 ) $ 874,641 Total average loans, net of unearned income $ 18,479,793 $ 2,423,078 $ — $ 256,523 $ 21,159,394 Total average assets (5) 46,303,582 2,449,763 325,939 (699,012 ) 48,380,272 Total average deposits 41,043,731 1,303,542 — 397,875 42,745,148 Year ended December 31, 2016 Net interest income (expense) $ 1,040,712 $ 53,582 $ (49 ) $ 56,278 $ 1,150,523 Provision for credit losses (93,885 ) (1,812 ) — (10,982 ) (106,679 ) Noninterest income 320,421 2,713 49,365 84,053 456,552 Noninterest expense (3) (632,264 ) (12,379 ) (15,546 ) (199,608 ) (859,797 ) Income before income tax expense (4) $ 634,984 $ 42,104 $ 33,770 $ (70,259 ) $ 640,599 Total average loans, net of unearned income $ 16,047,545 $ 2,025,381 $ — $ 210,665 $ 18,283,591 Total average assets (5) 41,494,321 2,047,513 338,848 106,769 43,987,451 Total average deposits 37,301,483 1,133,425 — 324,151 38,759,059 Year ended December 31, 2015 Net interest income $ 853,882 $ 44,412 $ 3 $ 108,128 $ 1,006,425 (Provision for) reduction of credit losses (94,913 ) (2,716 ) — 1,946 (95,683 ) Noninterest income 272,862 2,011 70,857 127,064 472,794 Noninterest expense (3) (578,888 ) (12,185 ) (14,699 ) (174,190 ) (779,962 ) Income before income tax expense (4) $ 452,943 $ 31,522 $ 56,161 $ 62,948 $ 603,574 Total average loans, net of unearned income $ 12,984,646 $ 1,592,065 $ — $ 186,230 $ 14,762,941 Total average assets (5) 38,438,858 1,457,461 337,884 612,174 40,846,377 Total average deposits 34,996,194 1,108,411 — 188,757 36,293,362 (1) Global Commercial Bank’s and SVB Capital’s components of net interest income, noninterest income, noninterest expense and total average assets are shown net of noncontrolling interests for all periods presented. Noncontrolling interest is included within "Other Items". (2) The "Other Items" column reflects the adjustments necessary to reconcile the results of the operating segments to the consolidated financial statements prepared in conformity with GAAP. Net interest income consists primarily of interest earned from our fixed income investment portfolio, net of FTP. Noninterest income consists primarily of gains on equity warrant assets, income from noncontrolling interests and gains or losses on the sale of fixed income securities. Noninterest expense consists primarily of expenses associated with corporate support functions such as finance, human resources, marketing, legal and other expenses. (3) The Global Commercial Bank segment includes direct depreciation and amortization of $24.9 million , $24.8 million and $20.3 million for 2017 , 2016 and 2015 , respectively. (4) The internal reporting model used by management to assess segment performance does not calculate income tax expense by segment. Our effective tax rate is a reasonable approximation of the segment rates. (5) Total average assets equal the greater of total average assets or the sum of total average liabilities and total average stockholders’ equity for each segment to reconcile the results to the consolidated financial statements prepared in conformity with GAAP.

Parent Company Only Condensed F

Parent Company Only Condensed Financial Information	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Only Condensed Financial Information	Parent Company Only Condensed Financial Information The condensed balance sheets of SVB Financial at December 31, 2017 and 2016 , and the related condensed statements of income, comprehensive income and cash flows for 2017 , 2016 and 2015 , are presented below: Condensed Balance Sheets December 31, (Dollars in thousands) 2017 2016 Assets: Cash and cash equivalents $ 457,324 $ 500,014 Investment securities 485,220 244,603 Net loans — 13,337 Other assets 196,974 197,220 Investment in subsidiaries: Bank subsidiary 3,762,542 3,423,427 Nonbank subsidiaries 90,540 113,928 Total assets $ 4,992,600 $ 4,492,529 Liabilities and SVBFG stockholders’ equity: 3.50% Senior Notes $ 347,303 $ 346,979 5.375% Senior Notes 348,189 347,586 7.0% Junior Subordinated Debentures — 54,493 Other liabilities 117,313 100,917 Total liabilities $ 812,805 $ 849,975 SVBFG stockholders’ equity 4,179,795 3,642,554 Total liabilities and SVBFG stockholders’ equity $ 4,992,600 $ 4,492,529 Condensed Statements of Income Year ended December 31, (Dollars in thousands) 2017 2016 2015 Interest income $ 2,077 $ 690 $ 964 Interest expense (34,932 ) (35,316 ) (34,169 ) Dividend income from bank subsidiary 90,000 40,000 — Gains on equity warrant assets, net (1) 54,555 37,892 70,963 Gains on investment securities, net 37,132 20,644 39,447 Fund management fees and other noninterest income (1) 24,613 21,913 2,286 General and administrative expenses (63,077 ) (55,139 ) (54,822 ) Income tax benefit (expense) 10,367 423 (14,448 ) Income before net income of subsidiaries 120,735 31,107 10,221 Equity in undistributed net income of nonbank subsidiaries 13,002 11,949 26,819 Equity in undistributed net income of bank subsidiary 356,769 339,629 306,864 Net income available to common stockholders $ 490,506 $ 382,685 $ 343,904 (1) Our consolidated statements of income for the years ended December 31, 2016 and 2015 were modified from prior periods’ presentation to conform to the current period's presentation, which reflects a new line item to separately disclose net gains on equity warrant assets. In prior periods, net gains on equity warrant assets were reported as a component of net gains on derivative instruments. We removed the line item "gains on derivative instruments, net" and reclassified all other gains on derivative instruments, net to other noninterest income. Condensed Statements of Comprehensive Income Year ended December 31, (Dollars in thousands) 2017 2016 2015 Net income available to common stockholders $ 490,506 $ 382,685 $ 343,904 Other comprehensive (loss) income, net of tax: Foreign currency translation gains (losses) 3,769 3,071 (1,492 ) Changes in unrealized holding gains and losses on AFS securities 22,285 654 (2,041 ) Equity in other comprehensive (losses) income of subsidiaries (50,956 ) 4,301 (23,767 ) Other comprehensive (loss) income, net of tax (24,902 ) 8,026 (27,300 ) Total comprehensive income $ 465,604 $ 390,711 $ 316,604 Condensed Statements of Cash Flows Year ended December 31, (Dollars in thousands) 2017 2016 2015 Cash flows from operating activities: Net income attributable to SVBFG $ 490,506 $ 382,685 $ 343,904 Adjustments to reconcile net income to net cash used for operating activities: Gains on equity warrant assets, net (54,555 ) (37,892 ) (70,963 ) Gains on investment securities, net (37,132 ) (20,644 ) (39,447 ) Net income of bank subsidiary (446,769 ) (379,629 ) (306,864 ) Net income on nonbank subsidiaries (13,002 ) (11,949 ) (26,819 ) Cash dividends from bank subsidiary 90,000 40,000 — Amortization of share-based compensation 36,900 35,494 32,239 Decrease (increase) in other assets 12,959 35,699 (30,638 ) Increase in other liabilities 11,774 15,293 28,985 Other, net 131 2,992 15,956 Net cash provided by (used for) operating activities 90,812 62,049 (53,647 ) Cash flows from investing activities: Net (increase) decrease in investment securities from purchases, sales and maturities (117,743 ) 54,737 31,380 Net decrease (increase) in loans 13,337 (3,478 ) 6,825 Increase in investment in bank subsidiary (38,927 ) (14,738 ) (378,286 ) Decrease in investment in nonbank subsidiaries 34,374 1,924 71,062 Net cash (used for) provided by investing activities (108,959 ) 38,445 (269,019 ) Cash flows from financing activities: Principal payments of long-term debt (51,546 ) — — Proceeds from issuance of common stock, ESPP and ESOP 27,003 26,147 22,410 Tax effect from stock exercises (1) — (3,640 ) 16,602 Net proceeds from issuance of long-term debt — — 346,431 Net cash (used for) provided by financing activities (24,543 ) 22,507 385,443 Net (decrease) increase in cash and cash equivalents (42,690 ) 123,001 62,777 Cash and cash equivalents at beginning of period 500,014 377,013 314,236 Cash and cash equivalents at end of period $ 457,324 $ 500,014 $ 377,013 (1) In 2017 we adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting on a prospective basis with no change to prior period amounts. See Note 2- "Summary of Significant Accounting Policies" of the "Notes to Consolidated Financial Statements" under Part II, Item 8 of this report for additional details.

Unaudited Quarterly Financial D

Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Financial Data	Unaudited Quarterly Financial Data Our supplemental consolidated financial information for each three month period in 2017 and 2016 are as follows: Three months ended (Dollars in thousands, except per share amounts) March 31, June 30, September 30, December 31, 2017: Interest income $ 320,926 $ 353,927 $ 385,271 $ 405,016 Interest expense 10,933 11,231 11,297 11,310 Net interest income 309,993 342,696 373,974 393,706 Provision for credit losses 30,734 15,806 23,522 22,242 Noninterest income 117,659 128,528 158,778 152,266 Noninterest expense 237,633 251,246 257,761 264,015 Income before income tax expense 159,285 204,172 251,469 259,715 Income tax expense (1) 51,405 71,656 97,351 135,051 Net income before noncontrolling interests 107,880 132,516 154,118 124,664 Net income attributable to noncontrolling interests (6,397 ) (9,323 ) (5,498 ) (7,454 ) Net income available to common stockholders (1) $ 101,483 $ 123,193 $ 148,620 $ 117,210 Earnings per common share—basic (1) $ 1.94 $ 2.34 $ 2.82 $ 2.22 Earnings per common share—diluted (1) 1.91 2.32 2.79 2.19 2016: Interest income $ 291,658 $ 293,992 $ 300,413 $ 307,333 Interest expense 10,237 10,656 11,252 10,728 Net interest income 281,421 283,336 289,161 296,605 Provision for credit losses (2) 33,475 36,746 20,004 16,454 Noninterest income 86,134 112,776 144,140 113,502 Noninterest expense (2) 203,899 199,939 220,773 235,186 Income before income tax expense 130,181 159,427 192,524 158,467 Income tax expense 53,584 65,047 76,877 54,825 Net income before noncontrolling interests 76,597 94,380 115,647 103,642 Net loss (income) attributable to noncontrolling interests 2,577 (1,416 ) (4,566 ) (4,176 ) Net income available to common stockholders $ 79,174 $ 92,964 $ 111,081 $ 99,466 Earnings per common share—basic $ 1.53 $ 1.79 $ 2.13 $ 1.91 Earnings per common share—diluted 1.52 1.78 2.12 1.89 (1) Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted in 2017, are tax benefits recognized associated with the adoption of ASU 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts. (2) Our consolidated statements of income for the quarterly periods in 2016 were modified from prior periods’ presentation to conform to the current period's presentation, which reflects our provision for loan losses and provision for unfunded credit commitments together as our “provision for credit losses”. In prior periods, our provision for unfunded credit commitments were reported separately as a component of noninterest expense.

Legal Matters

Legal Matters	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Legal Matters	Legal Matters Certain lawsuits and claims arising in the ordinary course of business have been filed or are pending against us and/or our affiliates, and we may from time to time be involved in other legal or regulatory proceedings. In accordance with applicable accounting guidance, we establish accruals for all such matters, including expected settlements, when we believe it is probable that a loss has been incurred and the amount of the loss is reasonably estimable. When a loss contingency is not both probable and estimable, we do not establish an accrual. Any such loss estimates are inherently uncertain, based on currently available information and are subject to management’s judgment and various assumptions. Due to the inherent subjectivity of these estimates and unpredictability of outcomes of legal proceedings, any amounts accrued may not represent the ultimate resolution of such matters. To the extent we believe any potential loss relating to such matters may have a material impact on our liquidity, consolidated financial position, results of operations, and/or our business as a whole and is reasonably possible but not probable, we aim to disclose information relating to such potential loss. We also aim to disclose information relating to any material potential loss that is probable but not reasonably estimable. In such cases, where reasonably practicable, we aim to provide an estimate of loss or range of potential loss. No disclosures are generally made for any loss contingencies that are deemed to be remote. Based upon information available to us, our review of lawsuits and claims filed or pending against us to date and consultation with our outside legal counsel, we have not recognized a material accrual liability for any such matters, nor do we currently expect that these matters will result in a material liability to the Company. However, the outcome of litigation and other legal and regulatory matters is inherently uncertain, and it is possible that one or more of such matters currently pending or threatened could have an unanticipated material adverse effect on our liquidity, consolidated financial position, results of operations, and/or our business as a whole, in the future.

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Use of Estimates and Assumptions	Use of Estimates and Assumptions The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Estimates may change as new information is obtained. Significant items that are subject to such estimates include measurements of fair value, the valuation of non-marketable and other securities, the valuation of equity warrant assets, the adequacy of the allowance for loan losses and the allowance for unfunded credit commitments and the recognition and measurement of income tax assets and liabilities. The following discussion provides additional background on our significant accounting policies.
Principles of Consolidation and Presentation	Principles of Consolidation and Presentation Our consolidated financial statements include the accounts of SVB Financial Group and consolidated entities. We consolidate voting entities in which we have control through voting interests or entities through which we have a controlling financial interest in a variable interest entity ("VIE"). We determine whether we have a controlling financial interest in a VIE by determining if we have (a) the power to direct the activities of the VIE that most significantly impact the entity’s economic performance, (b) the obligation to absorb the expected losses, or (c) the right to receive the expected returns of the entity. Generally, we have significant variable interests if our commitments to a limited partnership investment represent a significant amount of the total commitments to the entity. We also evaluate the impact of related parties on our determination of variable interests in our consolidation conclusions. We consolidate VIEs in which we are the primary beneficiary based on a controlling financial interest. If we are not the primary beneficiary of a VIE, we record our pro-rata interests or our cost basis in the VIE, as appropriate, based on other accounting guidance within GAAP. VIEs are entities where investors lack sufficient equity at risk for the entity to finance its activities without additional subordinated financial support or equity investors and, as a group, lack one of the following characteristics: (a) the power to direct the activities that most significantly impact the entity’s economic performance, (b) the obligation to absorb the expected losses of the entity, or (c) the right to receive the expected returns of the entity. We assess VIEs to determine if we are the primary beneficiary of a VIE. A primary beneficiary is defined as a variable interest holder that has a controlling financial interest. A controlling financial interest requires both: (a) the power to direct the activities that most significantly impact the VIEs economic performance, and (b) the obligation to absorb losses or receive benefits of a VIE that could potentially be significant to a VIE. Under this analysis, we also evaluate kick-out rights and other participating rights, which could provide us a controlling financial interest. The primary beneficiary of a VIE is required to consolidate the VIE. We also evaluate fees paid to managers of our limited partnership investments. We exclude those fee arrangements that are not deemed to be variable interests from the analysis of our interests in our investments in VIEs and the determination of a primary beneficiary, if any. Fee arrangements based on terms that are customary and commensurate with the services provided are deemed not to be variable interests and are, therefore, excluded. All significant intercompany accounts and transactions with consolidated entities have been eliminated. We have not provided financial or other support during the periods presented to any VIE that we were not previously contractually required to provide.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash on hand, cash balances due from banks, interest-earning deposits, Federal Reserve deposits, federal funds sold, securities purchased under agreements to resell and other short-term investment securities. For the consolidated statements of cash flows, we consider cash equivalents to be investments that are readily convertible to known amounts of cash, so near to their maturity that they present an insignificant risk of change in fair value due to changes in market interest rates, and purchased in conjunction with our cash management activities.
Available-for-Sale Securities	Available-for-Sale Securities Our available-for-sale securities portfolio is a fixed income investment portfolio that is managed to earn an appropriate portfolio yield over the long-term while maintaining sufficient liquidity and credit diversification and meeting our asset/liability management objectives. Unrealized gains and losses on available-for-sale securities, net of applicable taxes, are reported in accumulated other comprehensive income, which is a separate component of SVBFG's stockholders' equity, until realized. We analyze available-for-sale securities for other-than-temporary impairment each quarter. Market valuations represent the current fair value of a security at a specified point in time and incorporates the risk of timing of interest due and the return of principal over the contractual life of each security. Gains and losses on securities are realized when there is a sale of the security prior to maturity. A credit downgrade represents an increased level of risk of other-than-temporary impairment, and as a part of our consideration of recording an other-than-temporary impairment we will assess the issuer's ability to service the debt and to repay the principal at contractual maturity. We apply the other-than-temporary impairment standards of ASC 320, Investments-Debt and Equity Securities . For our debt securities, we have the intent and ability to hold these securities until we recover our cost less any credit-related loss. We separate the amount of the other-than-temporary impairment, if any, into the amount that is credit related (credit loss component) and the amount due to all other factors. The credit loss component is recognized in earnings and is the difference between a security's amortized cost basis and the present value of expected future cash flows discounted at the security's effective interest rate. The amount due to all other factors is recognized in other comprehensive income. We consider numerous factors in determining whether a credit loss exists and the period over which the debt security is expected to recover. The following list is not meant to be all inclusive. All of the following factors are considered: • The length of time and the extent to which the fair value has been less than the amortized cost basis (severity and duration); • Adverse conditions specifically related to the security, an industry, or geographic area; for example, changes in the financial condition of the issuer of the security, or in the case of an asset-backed debt security, changes in the financial condition of the underlying loan obligors. Examples of those changes include any of the following: ◦ Changes in technology; ◦ The discontinuance of a segment of the business that may affect the future earnings potential of the issuer or underlying loan obligors of the security; and ◦ Changes in the quality of the credit enhancement. • The historical and implied volatility of the fair value of the security; • The payment structure of the debt security and the likelihood of the issuer being able to make payments that increase in the future; • Failure of the issuer of the security to make scheduled interest or principal payments; • Any changes to the rating of the security by a rating agency; and • Recoveries or additional declines in fair value after the balance sheet date. In accordance with ASC 310-20, Receivables-Nonrefundable Fees and Other Costs , we use estimates of future principal prepayments, provided by third-party market-data vendors, in addition to actual principal prepayment experience to calculate the constant effective yield necessary to apply the effective interest method in the amortization of purchase discounts or premiums on mortgage-backed securities and fixed rate collateralized mortgage obligations (“CMO”). The accretion and amortization of discounts and premiums, respectively, are included in interest income over the contractual terms of the underlying securities replicating the effective interest method.
Held-to-Maturity Securities	Held-to-Maturity Securities Debt securities purchased in which we have the positive intent and ability to hold to its maturity are classified as held-to-maturity securities and are recorded at amortized cost. Transfers of investment securities into the held-to-maturity category from the available-for-sale category are made at fair value at the date of transfer. The net unrealized gains, net of tax, are retained in other comprehensive income, and the carrying value of the held-to-maturity securities are amortized over the life of the securities in a manner consistent with the amortization of a premium or discount. Our decision to re-designate the securities was based on our ability and intent to hold these securities to maturity.
Non-Marketable and Other Securities	Non-Marketable and Other Securities Non-marketable and other securities include investments in venture capital and private equity funds, SPD Silicon Valley Bank Co., Ltd. (the Bank's joint venture bank in China ("SPD-SVB")), debt funds, private and public portfolio companies and investments in qualified affordable housing projects. A majority of these investments are managed through our SVB Capital funds business in funds of funds and direct venture funds. Our accounting for investments in non-marketable and other securities depends on several factors, including the level of ownership, power to control and the legal structure of the subsidiary making the investment. As further described below, we base our accounting for such securities on: (i) fair value accounting, (ii) equity method accounting, (iii) cost method accounting, and (iv) the proportional amortization method which is used only for qualified affordable housing projects.
Fair Value Accounting	Fair Value Accounting Our managed funds are investment companies under the AICPA Audit and Accounting Guide for Investment Companies (codified in ASC 946) and accordingly, these funds report their investments at estimated fair value, with unrealized gains and losses resulting from changes in fair value reflected as investment gains or losses in our consolidated statements of income. Our non-marketable and other securities recorded pursuant to fair value accounting consist of our investments through the following funds: • Funds of funds, which make investments in venture capital and private equity funds, • Direct venture funds, which make equity investments in privately held companies
Equity Method	Equity Method Our equity method non-marketable securities consist of investments in venture capital and private equity funds, privately-held companies, debt funds, and joint ventures. Our equity method non-marketable securities and related accounting policies are described as follows: • Equity securities, such as preferred or common stock in privately-held companies in which we hold a voting interest of at least 20 percent , or in which we have the ability to exercise significant influence over the investees' operating and financial policies through board involvement or other influence, are accounted for under the equity method. • Investments in limited partnerships in which we hold voting interests of more than 5 percent , or in which we have the ability to exercise significant influence over the partnerships' operating and financial policies, are accounted for using the equity method. • Our China Joint Venture partnership, for which we have 50 percent ownership, is accounted for under the equity method. We recognize our proportionate share of the results of operations of these equity method investees in our results of operations, based on the most current financial information available from the investee. We review our investments accounted for under the equity method at least quarterly for possible other-than-temporary impairment. Our review typically includes an analysis of facts and circumstances for each investment, the expectations of the investment's future cash flows and capital needs, variability of its business and the company's exit strategy. For our fund investments, we utilize the net asset value per share as provided by the general partners of the fund investments. We account for differences between our measurement date and the date of the fund investment's net asset value by using the most recent available financial information from the investee general partner, for example September 30 th , for our December 31 st consolidated financial statements. We adjust the value of our investments for any contributions paid, distributions received from the investment, and known significant fund transactions or market events about which we are aware through information provided by the fund managers or from publicly available transaction data during the reporting period. We reduce our investment value when we consider declines in value to be other-than-temporary and recognize the estimated loss as a loss on investment securities, a component of noninterest income.
Cost Method	Cost Method Our cost method non-marketable securities and related accounting policies are described as follows: • Equity securities, such as preferred or common stock in privately-held companies in which we hold an ownership interest in which we do not have the ability to exercise significant influence over the investees' operating and financial policies, are accounted for under the cost method. • Investments in limited partnerships in which we hold voting interests of less than 5 percent and in which we do not have the ability to exercise significant influence over the partnerships' operating and financial policies, are accounted for under the cost method. These non-marketable securities include investments in venture capital and private equity funds. We record these investments at cost and recognize distributions or returns received from net accumulated earnings of the investee since the date of acquisition as income. Our share of net accumulated earnings of the investee after the date of investment are recognized in consolidated net income only to the extent distributed by the investee. Distributions or returns received in excess of accumulated earnings are considered a return of investment and are recorded as reductions in the cost basis of the investment. We review our investments accounted for under the cost method at least quarterly for possible other-than-temporary impairment. Our review typically includes an analysis of facts and circumstances of each investment, the expectations of the investment's future cash flows and capital needs, variability of its business and the company's exit strategy. To help determine impairment, if any, for our fund investments, we utilize the net asset value per share as provided by the general partners of the fund investments. We reduce our investment value when we consider declines in value to be other-than-temporary and recognize the estimated loss as a loss on investment securities, a component of noninterest income. Gains or losses on cost method investment securities that result from a portfolio company being acquired by a publicly traded company are determined using the fair value of the consideration received when the acquisition occurs. The resulting gains or losses are recognized in consolidated net income in the period of acquisition. Proportional Amortization Method In order to fulfill our responsibilities under the Community Reinvestment Act, we invest as a limited partner in low income housing partnerships that operate qualified affordable housing projects and generate tax benefits, including federal low income housing tax credits, for investors. The partnerships are deemed to be VIEs because they do not have sufficient equity investment at risk and are structured with non-substantive voting rights. We are not the primary beneficiary of the VIEs and do not consolidate them. Our investments in low income housing partnerships are recorded in non-marketable and other securities within our investment securities portfolio on the consolidated balance sheet. As a practical expedient, we amortize the investment in proportion to the allocated tax benefits under the proportional amortization method of accounting and present such benefits net of investment amortization in income tax expense.
Loans	Loans Loans are reported at the principal amount outstanding, net of unearned loan fees. Unearned loan fees reflect unamortized deferred loan origination and commitment fees net of unamortized deferred loan origination costs. In addition to cash loan fees, we often obtain equity warrant assets that give us an option to purchase a position in a client company's stock in consideration for providing credit facilities. The grant date fair values of these equity warrant assets are deemed to be loan fees and are deferred as unearned income and recognized as an adjustment of loan yield through loan interest income. The net amount of unearned loan fees is amortized into loan interest income over the contractual terms of the underlying loans and commitments using the constant effective yield method, adjusted for actual loan prepayment experience, or the straight-line method, as applicable.
Allowance for Loan Losses	Allowance for Loan Losses The allowance for loan losses considers credit risk and is established through a provision for loan losses charged to expense. Our allowance for loan losses is established for estimated loan losses that are probable and incurred but not yet realized. Our evaluation process is designed to determine that the allowance for loan losses is appropriate at the balance sheet date. The process of estimating loan losses is inherently imprecise. We maintain a systematic process for the evaluation of individual loans and pools of loans for inherent risk of loan losses. At the time of approval, each loan in our portfolio is assigned a Credit Risk Rating and industry niche. Credit Risk Ratings are assigned on a scale of 1 to 10, with 1 representing loans with a low risk of nonpayment, 9 representing loans with the highest risk of nonpayment, and 10 representing loans which have been charged-off. The credit risk ratings for each loan are monitored and updated on an ongoing basis. This Credit Risk Rating process includes, but is not limited to, consideration of such factors as payment status, the financial condition and operating performance of the borrower, borrower compliance with loan covenants, underlying collateral values and performance trends, the degree of access to additional capital, the presence of credit enhancements such as third party guarantees (where applicable), the degree to which the borrower is sensitive to external factors, the depth and experience of the borrower's management team, potential loan concentrations, and general economic conditions. Our policies require a committee of senior management to review, at least quarterly, credit relationships with a credit risk rating of 5 through 9 that exceed specific dollar values. Our review process evaluates the appropriateness of the credit risk rating and allocation of the allowance for loan losses, as well as other account management functions. The allowance for loan losses is determined based on a qualitative analysis and a formula allocation for similarly risk-rated loans by portfolio segment and individually for impaired loans. The formula allocation provides the average loan loss experience for each portfolio segment, which considers our quarterly historical loss experience since the year 2000, both by risk-rating category and client industry sector. The resulting loan loss factors for each risk-rating category and client industry sector are ultimately applied to the respective period-end client loan balances for each corresponding risk-rating category by client industry sector to provide an estimation of the allowance for loan losses. The probable loan loss experience for any one year period of time is reasonably expected to be greater or less than the average as determined by the loss factors. As such, management applies a qualitative allocation to the results of the aforementioned model to ascertain the total allowance for loan losses. This qualitative allocation is based on management's assessment of the risks that may lead to a loan loss experience different from our historical loan loss experience. Based on management's prediction or estimate of changing risks in the lending environment, the qualitative allocation may vary significantly from period to period and includes, but is not limited to, consideration of the following factors: • Changes in lending policies and procedures, including underwriting standards and collections, and charge-off and recovery practices; • Changes in national and local economic business conditions, including the market and economic condition of our clients' industry sectors; • Changes in the nature of our loan portfolio; • Changes in experience, ability, and depth of lending management and staff; • Changes in the trend of the volume and severity of past due and classified loans; • Changes in the trend of the volume of nonaccrual loans, troubled debt restructurings, and other loan modifications; • Reserve floor for portfolio segments that would not draw a minimum reserve based on the lack of historical loan loss experience; • Reserve for large funded loan exposure; • Reserve for performing impaired loan exposure; and • Other factors as determined by management from time to time. While the evaluation process of our allowance for loan losses uses historical and other objective information, the classification of loans and the establishment of the allowance for loan losses rely, to a great extent, on the judgment and experience of our management.
Allowance for Unfunded Credit Commitments	Allowance for Unfunded Credit Commitments We record a liability for probable and estimable incurred losses associated with our unfunded credit commitments being funded and subsequently being charged off. Each quarter, every unfunded client credit commitment is allocated to a credit risk-rating in accordance with each client's credit risk rating and portfolio segment. We use the segment specific historical loan loss factors described under our allowance for loan losses to calculate the loan loss experience if unfunded credit commitments are funded. Separately, we use historical trends to calculate a probability of an unfunded credit commitment being funded. We apply the loan funding probability factor to risk-factor adjusted unfunded credit commitments by credit risk-rating and portfolio segment to derive the allowance for unfunded credit commitments, similar to funded loans. The allowance for unfunded credit commitments also includes certain qualitative allocations as deemed appropriate by management. We include the allowance for unfunded credit commitments in other liabilities and the related provision in our provision for credit losses.
Uncollectible Loans and Write-offs	Uncollectible Loans and Write-offs Our charge-off policy applies to all loans, regardless of portfolio segment. Commercial loans are considered for a full or partial charge-off in the event that principal or interest is over 180 days past due and the loan lacks sufficient collateral and it is not in the process of collection, provided that a loss event has been defined and the charge-off is consistent with GAAP. Consumer loans are considered for a full or partial charge-off in the event that principal or interest is over 120 days past due and the loan lacks sufficient collateral and it is not in the process of collection, provided that a loss event has been defined and the charge-off is consistent with GAAP. We also consider writing off loans in the event of any of the following circumstances: 1) the loan, or a portion of the loan is deemed uncollectible due to: a) the borrower's inability to make recurring payments, b) material changes in the borrower's financial condition, or c) the expected sale of all or a portion of the borrower's business is insufficient to repay the loan in full, or 2) the loan has been identified for charge-off by regulatory authorities.
Troubled Debt Restructurings (TDRs)	Troubled Debt Restructurings A TDR arises from the modification of a loan where we have granted a concession to the borrower related to the borrower's financial difficulties that we would not have otherwise considered for economic or legal reasons. These concessions may include: (1) deferral of payment for more than an insignificant period of time that does not include sufficient offsetting borrower concessions; (2) interest rate reductions; (3) extension of the maturity date outside of ordinary course extension; (4) principal forgiveness; and/or (5) reduction of accrued interest. We use the factors in ASC 310-40, Receivables, Troubled Debt Restructurings by Creditors, in analyzing when a borrower is experiencing financial difficulty, and when we have granted a concession, both of which must be present for a restructuring to meet the criteria of a TDR. If we determine that a TDR exists, we measure impairment based on the present value of expected future cash flows discounted at the loan's effective interest rate, except that as a practical expedient, we may also measure impairment based on a loan's observable market price, or the fair value of the collateral less selling costs if the loan is a collateral-dependent loan.
Impaired Financing Receivable, Policy [Policy Text Block]	Impaired Loans A loan is considered impaired when, based upon currently known information, it is deemed probable that we will be unable to collect all amounts due according to the contractual terms of the agreement. On a quarterly basis, we review our loan portfolio for impairment. Within each class of loans, we review individual loans for impairment based on credit risk ratings. Loans risk-rated 5 through 7 are performing loans; however, we consider them as demonstrating higher risk, which requires more frequent review of the individual exposures; these translate to an internal rating of "Performing (Criticized)" and could be classified as a performing impaired loan. For each loan identified as impaired, we measure the impairment based upon the present value of expected future cash flows discounted at the loan's effective interest rate. In limited circumstances, we may measure impairment based on the loan's observable market price or the fair value of the collateral less selling costs if the loan is collateral dependent. Impaired collateral dependent loans will have independent appraisals completed and accepted at least annually. The fair value of the collateral will be determined by the most recent appraisal, as adjusted to reflect a reasonable marketing period for the sale of the asset(s) and an estimate of reasonable selling expenses. If it is determined that the value of an impaired loan is less than the recorded investment in the loan, net of previous charge-offs and payments collected, we recognize impairment through the allowance for loan losses as determined by our analysis.
Nonaccrual Loans	Nonaccrual Loans Loans are placed on nonaccrual status when they become 90 days past due as to principal or interest payments (unless the principal and interest are well secured and in the process of collection); or when we have determined, based upon currently known information, that the timely collection of principal or interest is not probable. When a loan is placed on nonaccrual status, the accrued interest and fees are reversed against interest income and the loan is accounted for using the cost recovery method thereafter until qualifying for return to accrual status. Historically, loans that have been placed on nonaccrual status have remained as nonaccrual loans until the loan is either charged-off, or the principal balances have been paid off. For a loan to be returned to accrual status, all delinquent principal and interest must become current in accordance with the terms of the loan agreement and future collection of remaining principal and interest must be deemed probable. We apply a cost recovery method in which all cash received is applied to the loan principal until it has been collected. Under this approach, interest income is recognized after total cash flows received exceed the recorded investment at the date of initial nonaccrual. All of our nonaccrual loans have credit risk ratings of 8 or 9 and are classified under the nonperforming impaired category.
Premises and Equipment	Premises and Equipment Premises and equipment are reported at cost less accumulated depreciation and amortization. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets or the terms of the related leases, whichever is shorter. The maximum estimated useful lives by asset classification are as follows: Leasehold improvements Lesser of lease term or asset life Furniture and equipment 7 years Computer software 3-7 years Computer hardware 3-5 years We capitalize the costs of computer software developed or obtained for internal use, including costs related to developed software, purchased software licenses and certain implementation costs. For property and equipment that is retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts and the resulting gain or loss is included in noninterest expense in consolidated net income.
Lease Obligations	Lease Obligations We lease all of our properties. At the inception of the lease, each property is evaluated to determine whether the lease will be accounted for as an operating or capital lease. For leases that contain rent escalations or landlord incentives, we record the total rent payable during the lease term, using the straight-line method over the term of the lease and record the difference between the minimum rents paid and the straight-line rent as lease obligations. We had no capitalized lease obligations at December 31, 2017 and 2016 .
Fair Value Measurements	Fair Value Measurements Our available-for-sale securities, derivative instruments and certain marketable, non-marketable and other securities are financial instruments recorded at fair value on a recurring basis. We make estimates regarding valuation of assets and liabilities measured at fair value in preparing our consolidated financial statements. Fair Value Measurement-Definition and Hierarchy Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (the “exit price”) in an orderly transaction between market participants at the measurement date. There is a three-level hierarchy for disclosure of assets and liabilities recorded at fair value. The classification of assets and liabilities within the hierarchy is based on whether the inputs to the valuation methodology used for measurement are observable or unobservable and the significance of those inputs in the fair value measurement. Observable inputs reflect market-derived or market-based information obtained from independent sources, while unobservable inputs reflect our estimates about market data and views of market participants. The three levels for measuring fair value are based on the reliability of inputs and are as follows: Level 1 Fair value measurements based on quoted prices in active markets for identical assets or liabilities that we have the ability to access. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of these instruments does not entail a significant degree of judgment. Assets utilizing Level 1 inputs include U.S. Treasury securities, exchange-traded equity securities and certain marketable securities accounted for under fair value accounting. Level 2 Fair value measurements based on quoted prices in markets that are not active or for which all significant inputs are observable, directly or indirectly. Valuations for the available-for-sale securities are provided by independent pricing service providers who have experience in valuing these securities and are compared to the average of quoted market prices obtained from independent brokers. We perform a monthly analysis on the values received from third parties to ensure that the prices represent a reasonable estimate of the fair value. The procedures include, but are not limited to, initial and ongoing review of third party pricing methodologies, review of pricing trends and monitoring of trading volumes. Additional corroboration, such as obtaining a non-binding price from a broker, may be obtained depending on the frequency of trades of the security and the level of liquidity or depth of the market. We ensure prices received from independent brokers represent a reasonable estimate of the fair value through the use of observable market inputs including comparable trades, yield curve, spreads and, when available, market indices. As a result of this analysis, if the Company determines that there is a more appropriate fair value based upon the available market data, the price received from the third party is adjusted accordingly. Below is a summary of the significant inputs used for each class of Level 2 assets and liabilities: U.S. agency debentures: Fair value measurements of U.S. agency debentures are based on the characteristics specific to bonds held, such as issuer name, issuance date, coupon rate, maturity date and any applicable issuer call option features. Valuations are based on market spreads relative to similar term benchmark market interest rates, generally U.S. Treasury securities. Agency-issued mortgage-backed securities: Agency-issued mortgage-backed securities are pools of individual conventional mortgage loans underwritten to U.S. agency standards with similar coupon rates, tenor, and other attributes such as geographic location, loan size and origination vintage. Fair value measurements of these securities are based on observable price adjustments relative to benchmark market interest rates taking into consideration estimated loan prepayment speeds. Agency-issued collateralized mortgage obligations: Agency-issued collateralized mortgage obligations are structured into classes or tranches with defined cash flow characteristics and are collateralized by U.S. agency-issued mortgage pass-through securities. Fair value measurements of these securities incorporate similar characteristics of mortgage pass-through securities such as coupon rate, tenor, geographic location, loan size and origination vintage, in addition to incorporating the effect of estimated prepayment speeds on the cash flow structure of the class or tranche. These measurements incorporate observable market spreads over an estimated average life after considering the inputs listed above. Agency-issued commercial mortgage-backed securities: Fair value measurements of these securities are based on spreads to benchmark market interest rates (usually U.S. Treasury rates or rates observable in the swaps market), prepayment speeds, loan default rate assumptions and loan loss severity assumptions on underlying loans. Municipal bonds and notes: Bonds issued by municipal governments generally have stated coupon rates, final maturity dates and are subject to being called ahead of the final maturity date at the option of the issuer. Fair value measurements of these securities are priced based on spreads to other municipal benchmark bonds with similar characteristics; or, relative to market rates on U.S. Treasury bonds of similar maturity. Interest rate derivative assets and liabilities: Fair value measurements of interest rate derivatives are priced considering the coupon rate of the fixed leg of the contract and the variable coupon rate on the floating leg of the contract. Valuation is based on both spot and forward rates on the swap yield curve and the credit worthiness of the contract counterparty. Foreign exchange forward and option contract assets and liabilities: Fair value measurements of these assets and liabilities are priced based on spot and forward foreign currency rates and option volatility assumptions. Equity warrant assets (public portfolio): Fair value measurements of equity warrant assets of publicly-traded portfolio companies are valued based on the Black-Scholes option pricing model. The model uses the price of publicly-traded companies (underlying stock price), stated strike prices, warrant expiration dates, the risk-free interest rate and market-observable option volatility assumptions. Level 3 The fair value measurement is derived from valuation techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect our own estimates of assumptions we believe market participants would use in pricing the asset. The valuation techniques are consistent with the market approach, income approach and/or the cost approach used to measure fair value. Below is a summary of the valuation techniques used for each class of Level 3 assets: Other venture capital investments: Fair value measurements are based on consideration of a range of factors including, but not limited to, the price at which the investment was acquired, the term and nature of the investment, local market conditions, values for comparable securities, and as it relates to the private company, the current and projected operating performance, exit strategies and financing transactions subsequent to the acquisition of the investment. The significant unobservable inputs used in the fair value measurement include the information about each portfolio company, including actual and forecasted results, cash position, recent or planned transactions and market comparable companies. Significant changes to any one of these inputs in isolation could result in a significant change in the fair value measurement, however, we generally consider all factors available through ongoing communication with the portfolio companies and venture capital fund managers to determine whether there are changes to the portfolio company or the environment that indicate a change in the fair value measurement. Other securities: Fair value measurements of equity securities of public companies are priced based on quoted market prices less a discount if the securities are subject to certain sales restrictions. Certain sales restriction discounts generally range from 10 percent to 20 percent depending on the duration of the sale restrictions which typically range from three to six months. Equity warrant assets (public portfolio): Fair value measurements of equity warrant assets of publicly-traded portfolio companies are valued based on the Black-Scholes option pricing model. The model uses the price of publicly-traded companies (underlying stock price), stated strike prices, warrant expiration dates, the risk-free interest rate and market-observable option volatility assumptions. Modeled asset values are further adjusted by applying a discount of up to 20 percent for certain warrants that have certain sales restrictions or other features that indicate a discount to fair value is warranted. As sale restrictions are lifted, discounts are adjusted downward to zero once all restrictions expire or are removed. Equity warrant assets (private portfolio): Fair value measurements of equity warrant assets of private portfolio companies are priced based on a Black-Scholes option pricing model to estimate the asset value by using stated strike prices, option expiration dates, risk-free interest rates and option volatility assumptions. Option volatility assumptions used in the Black-Scholes model are based on public market indices whose members operate in similar industries as companies in our private company portfolio. Option expiration dates are modified to account for estimates to actual life relative to stated expiration. Overall model asset values are further adjusted for a general lack of liquidity due to the private nature of the associated underlying company. There is a direct correlation between changes in the volatility and remaining life assumptions in isolation and the fair value measurement while there is an inverse correlation between changes in the liquidity discount assumption and the fair value measurement. It is our policy to maximize the use of observable inputs and minimize the use of unobservable inputs when developing fair value measurements. When available, we use quoted market prices to measure fair value. If market prices are not available, fair value measurement is based upon valuation approaches that use primarily market-based or independently-sourced market parameters, including interest rate yield curves, prepayment speeds, option volatilities and currency rates. Substantially all of our financial instruments use the foregoing methodologies, and are categorized as a Level 1 or Level 2 measurement in the fair value hierarchy. However, in certain cases, when market observable inputs for our valuation techniques may not be readily available, we are required to make judgments about assumptions we believe market participants would use in estimating the fair value of the financial instrument, and based on the significance of those judgments, the measurement may be determined to be a Level 3 fair value measurement. The degree of management judgment involved in determining the fair value of a financial instrument is dependent upon the availability of quoted market prices or observable market parameters. For financial instruments that trade actively and have quoted market prices or observable market parameters, there is minimal subjectivity involved in measuring fair value. When observable market prices and parameters are not fully available, management judgment is necessary to estimate fair value. For inactive markets, there is little information, if any, to evaluate if individual transactions are orderly. Accordingly, we are required to estimate, based upon all available facts and circumstances, the degree to which orderly transactions are occurring and provide more weighting to price quotes that are based upon orderly transactions. In addition, changes in the market conditions may reduce the availability of quoted prices or observable data. For example, reduced liquidity in the capital markets or changes in secondary market activities could result in observable market inputs becoming unavailable. Therefore, when market data is not available, we use valuation techniques requiring more management judgment to estimate the appropriate fair value measurement. Accordingly, the degree of judgment exercised by management in determining fair value is greater for financial assets and liabilities categorized as Level 3.
Fee-based Services Revenue Recognition	Fee-based Services Revenue Recognition Refer to Note 14—“Noninterest Income” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report for our fee-based services revenue recognition policies for our contracts with customers.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Our federal, state and foreign income tax provisions are based upon taxes payable for the current year, current year changes in deferred taxes related to temporary differences between the tax basis and financial statement balances of assets and liabilities, and a reserve for uncertain tax positions. Deferred tax assets and liabilities are included in the consolidated financial statements at currently enacted income tax rates applicable to the period in which the deferred tax assets and liabilities are expected to be realized. As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. We file a consolidated federal income tax return, and consolidated, combined, or separate state income tax returns as appropriate. Our foreign incorporated subsidiaries file tax returns in the applicable foreign jurisdictions. We record interest and penalties related to unrecognized tax benefits in other noninterest expense, a component of consolidated net income.
Share-Based Compensation	Share-Based Compensation For all stock-based awards granted, stock-based compensation expense is amortized on a straight-line basis over the requisite service period, including consideration of vesting conditions and anticipated forfeitures. The fair value of stock options are measured using the Black-Scholes option-pricing model and the fair value for restricted stock awards and restricted stock units are based on the quoted price of our common stock on the date of grant.
Earnings Per Share	Earnings Per Share Basic earnings per common share is computed using the weighted average number of common stock shares outstanding during the period. Diluted earnings per common share is computed using the weighted average number of common stock shares and potential common shares outstanding during the period. Potential common shares consist of stock options, ESPP shares and restricted stock units. Common stock equivalent shares are excluded from the computation if the effect is antidilutive.
Derivative Financial Instruments	Derivative Financial Instruments All derivative instruments are recorded on the balance sheet at fair value. The accounting for changes in fair value of a derivative financial instrument depends on whether the derivative financial instrument is designated and qualifies as part of a hedging relationship and, if so, the nature of the hedging activity. Changes in fair value are recognized through earnings for derivatives that do not qualify for hedge accounting treatment, or that have not been designated in a hedging relationship. Fair Value Hedges For derivative instruments that are designated and qualify as a fair value hedge, the gain or loss on the hedging instrument is recorded in the statement of income in the same line item as the hedged item and is intended to offset the loss or gain on the hedged item attributable to the hedged risk. Any difference that does arise would be the result of hedge ineffectiveness, and impacts earnings. Equity Warrant Assets In connection with negotiated credit facilities and certain other services, we may obtain equity warrant assets giving us the right to acquire stock in primarily private, venture-backed companies in the technology and life science/healthcare industries. We hold these assets for prospective investment gains. We do not use them to hedge any economic risks nor do we use other derivative instruments to hedge economic risks stemming from equity warrant assets. We account for equity warrant assets in certain private and public client companies as derivatives when they contain net settlement terms and other qualifying criteria under ASC 815, Derivatives and Hedging . In general, equity warrant assets entitle us to buy a specific number of shares of stock at a specific price within a specific time period. Certain equity warrant assets contain contingent provisions, which adjust the underlying number of shares or purchase price upon the occurrence of certain future events. Substantially all of our warrant agreements contain net share settlement provisions, which permit us to receive at exercise a share count equal to the intrinsic value of the warrant divided by the share price (otherwise known as a “cashless” exercise). These equity warrant assets are recorded at fair value and are classified as derivative assets, a component of other assets, on our consolidated balance sheet at the time they are obtained. The grant date fair values of equity warrant assets received in connection with the issuance of a credit facility are deemed to be loan fees and recognized as an adjustment of loan yield through loan interest income. Similar to other loan fees, the yield adjustment related to grant date fair value of warrants is recognized over the life of that credit facility. Any changes in fair value from the grant date fair value of equity warrant assets will be recognized as increases or decreases to other assets on our balance sheet and as net gains or losses on derivative instruments, in noninterest income, a component of consolidated net income. When a portfolio company completes an IPO on a publicly reported market or is acquired, we may exercise these equity warrant assets for shares or cash. In the event of an exercise for shares, the basis or value in the securities is reclassified from other assets to investment securities on the balance sheet on the latter of the exercise date or corporate action date. The shares in public companies are classified as available-for-sale securities (provided they do not have a significant restriction from sale). Changes in fair value of securities designated as available-for-sale, after applicable taxes, are reported in accumulated other comprehensive income, which is a separate component of SVBFG stockholders' equity. The shares in private companies are classified as non-marketable securities. Typically, we account for these securities at cost and only record adjustments to the value at the time of exit or liquidation though gains or losses on investments securities, in noninterest income, a component of consolidated net income. The fair value of the equity warrant assets portfolio is a critical accounting estimate and is reviewed quarterly. We value our equity warrant assets using a Black-Scholes option pricing model, which incorporates the following significant inputs: • An underlying asset value, which is estimated based on current information available in valuation reports, including any information regarding subsequent rounds of funding or performance of a company. • Stated strike price, which can be adjusted for certain warrants upon the occurrence of subsequent funding rounds or other future events. • Price volatility or risk associated with possible changes in the warrant price. The volatility assumption is based on historical price volatility of publicly traded companies within indices similar in nature to the underlying client companies issuing the warrant. The actual volatility input is based on the mean and median volatility for an individual public company within an index for the past 16 quarters, from which an average volatility was derived. • Actual data on cancellations and exercises of our warrants are utilized as the basis for determining the expected remaining life of the warrants in each financial reporting period. Warrants may be exercised in the event of acquisitions, mergers or IPOs, and cancelled due to events such as bankruptcies, restructuring activities or additional financings. These events cause the expected remaining life assumption to be shorter than the contractual term of the warrants. • The risk-free interest rate is derived from the Treasury yield curve and is calculated based on a weighted average of the risk-free interest rates that correspond closest to the expected remaining life of the warrant. • Other adjustments, including a marketability discount, are estimated based on management's judgment about the general industry environment. • Number of shares and contingencies associated with obtaining warrant positions such as the funding of associated loans. Foreign Exchange Forwards and Foreign Currency Option Contracts We enter into foreign exchange forward contracts and foreign currency option contracts with clients involved in international activities, either as the purchaser or seller, depending upon the clients' need. We also enter into an opposite-way forward or option contract with a correspondent bank to economically hedge client contracts to mitigate the fair value risk to us from fluctuations in currency rates. Settlement, credit and operational risks remain. We also enter into forward contracts with correspondent banks to economically hedge currency exposure risk related to certain foreign currency denominated assets and liabilities. These contracts are not designated as hedging instruments and are recorded at fair value in our consolidated balance sheets. The contracts generally have terms of one year or less, although we may have contracts extending for up to five years. Generally, we have not experienced nonperformance on these contracts, have not incurred credit losses, and anticipate performance by all counterparties to such agreements. Changes in the fair value of these contracts are recognized in consolidated net income under other noninterest income, a component of noninterest income. Period-end gross positive fair values are recorded in other assets and gross negative fair values are recorded in other liabilities. Interest Rate Contracts We sell interest rate contracts to clients who wish to mitigate their interest rate exposure. We economically reduce the interest rate risk from this business by entering into opposite way contracts with correspondent banks. We do not designate any of these contracts (which are derivative instruments) as qualifying for hedge accounting. Contracts in an asset position are included in other assets and contracts in a liability position are included in other liabilities. The net change in the fair value of these derivatives is recorded through other noninterest income, in noninterest income, a component of consolidated net income.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB issued a new accounting standard update (ASU 2014-09, Revenue from Contracts with Customers (Topic 606)), which provides revenue recognition guidance that is intended to create greater consistency with respect to how and when revenue from contracts with customers is shown in the income statement. The guidance requires that revenue from contracts with customers be recognized when transfer of control over goods or services is passed to customers in the amount of consideration expected to be received. Subsequent Accounting Standard Updates have been issued clarifying the original pronouncement (ASU 2016-08, ASU 2016-10, ASU 2016-12 and ASU 2016-20). The new standard and amendments will be effective January 1, 2018, either on a full retrospective approach or a modified retrospective approach. We plan to adopt the revenue guidance in the first quarter of 2018 using the modified retrospective transition approach to contracts which are not completed as of January 1, 2018. We completed a comprehensive scoping exercise to determine the revenue streams that are within the scope of this guidance and will recognize the cumulative-effect of adopting this guidance as an adjustment to opening retained earnings. The scope of this guidance explicitly excludes net interest income, including interest income earned from our loan and fixed income securities portfolios, as well as certain other noninterest income earned from our lending-, investment- and derivative-related activities. Based on our contract assessments, we did not identify any material changes to the timing or the amounts of our revenue recognition. There will be minor changes in the timing of recognizing fund management fees in noninterest income for a portion of our SVB Capital funds as the fees will be recognized at the time of distribution which typically occurs later in the fund life than had been previously recognized. Upon adoption, we will recognize a cumulative-effect adjustment to opening retained earnings of approximately $8 million on a pre-tax basis, with an immaterial impact to our net income on an ongoing basis. Furthermore, we will provide a disaggregation of our significant categories of revenue within the scope of this guidance and expand our qualitative disclosures of our noninterest income within the Consolidated Financial Statements beginning the first quarter of 2018. In January 2016, the FASB issued a new accounting standard update (ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (Topic 825)), which addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments. This guidance requires equity investments (except those accounted for under the equity method of accounting) to be measured at fair value with changes in fair value recognized in net income. The adoption of the new standard will result in the elimination of cost method accounting for equity investments and will impact our nonmarketable and other equity securities that are currently carried at cost. This guidance will be effective on January 1, 2018, and as a result, our equity investments measured at cost will be re-measured at fair value and the difference between cost and fair value will be recorded as a cumulative-effect adjustment to opening retained earnings as of January 1, 2018, for our cost method venture capital and private equity fund investments with readily determinable fair values. The adjustment to opening retained earnings for these investments will be approximately $100 million on a pre-tax basis and any subsequent changes in the fair value of these equity securities will be recorded as unrealized gains or losses in our consolidated statements of income. Additionally, in accordance with this guidance, net unrealized gains included in accumulated other comprehensive income of approximately $40 million on a pre-tax basis related to our available-for-sale equity securities, will be reclassified as an adjustment to retained earnings. Any subsequent changes in the fair value of these equity securities will be recorded as unrealized gains or losses in our consolidated statements of income. Furthermore, for purposes of disclosing the fair value of loans carried at amortized cost, we will update our valuation methods as necessary to conform to an “exit price” concept as required by the standard update. In February 2016, the FASB issued a new accounting standard update (ASU 2016-02, Leases (Topic 842)), which will require for all operating leases the recognition of a right-of-use asset and a lease liability, in the statement of financial position. The lease cost will be allocated over the lease term on a straight-line basis. This guidance will be effective on January 1, 2019, on a modified retrospective basis, with early adoption permitted. We plan to adopt the lease accounting guidance in the first quarter of 2019 and are currently evaluating the impact this guidance will have on our consolidated financial statements by reviewing our existing lease contracts and service contracts that may include embedded leases. We expect to recognize right-of-use assets and related lease liabilities associated predominantly with noncancelable operating leases included in the table of minimum future payments in the amount of $226 million as disclosed in Note 19—“Off-Balance Sheet Arrangements, Guarantees and Other Commitments” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report . In June 2016, the FASB issued a new accounting standard update (ASU 2016-13, Financial Instruments- Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments), which amends the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. This guidance will be effective January 1, 2020, on a modified retrospective approach, with early adoption permitted, but not before January 1, 2019. We currently have a working project team in place and subject matter experts to assist with our review of key interpretive issues and assist in the assessment of our existing credit loss forecasting models and processes against the new guidance to determine what modifications may be required. We are currently evaluating the impact this guidance will have on our financial position, results of operation and stockholders’ equity. In August 2016, the FASB issued a new accounting standard update (ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments), which clarifies the guidance on eight specific cash flow issues. This guidance will be effective January 1, 2018 and will be applied on a full retrospective basis beginning the first quarter of 2018. This guidance will impact the presentation between investing and operating activities within our consolidated statements of cash flows related to distributions and net gains from our nonmarketable and other securities portfol
Reclassifications	Reclassifications Certain prior period amounts, primarily related to the changes to our income statement presentation of net gains on derivative instruments and provision for unfunded credit commitments, have been reclassified to conform to current period presentations.

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Ownership Interests in Investments Held Under Fair Value Accounting	A summary of our ownership interests in the investments held under fair value accounting as of December 31, 2017 is presented in the following table: Limited partnership Company Direct and Indirect Ownership in Limited Partnership Managed funds of funds Strategic Investors Fund, LP 12.6 % Capital Preferred Return Fund, LP 20.0 Growth Partners, LP 33.0 Managed direct venture funds CP I, LP 10.7
Maximum Estimated Useful Lives by Asset Classification	The maximum estimated useful lives by asset classification are as follows: Leasehold improvements Lesser of lease term or asset life Furniture and equipment 7 years Computer software 3-7 years Computer hardware 3-5 years

Stockholders' Equity and EPS (T

Stockholders' Equity and EPS (Tables)	12 Months Ended
	Dec. 31, 2017
Equity and Earnings Per Share [Abstract]
Reclassification out of Accumulated Other Comprehensive Income	Accumulated Other Comprehensive (Loss) Income The following table summarizes the items reclassified out of accumulated other comprehensive income into the Consolidated Statements of Income for 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) Income Statement Location 2017 2016 2015 Reclassification adjustment for losses (gains) included in net income Gains on investment securities, net $ 5,189 $ (12,195 ) $ (1,201 ) Related tax (benefit) expense Income tax expense (2,098 ) 4,963 481 Total reclassification adjustment for losses (gains) included in net income, net of tax $ 3,091 $ (7,232 ) $ (720 )
Reconciliation of Basic EPS to Diluted EPS	The following is a reconciliation of basic EPS to diluted EPS for 2017 , 2016 and 2015 : Year ended December 31, (Dollars and shares in thousands, except per share amounts) 2017 2016 2015 Numerator: Net income available to common stockholders $ 490,506 $ 382,685 $ 343,904 Denominator: Weighted average common shares outstanding—basic 52,588 51,915 51,318 Weighted average effect of dilutive securities: Stock options and ESPP 385 254 387 Restricted stock units 333 180 211 Weighted average common shares outstanding—diluted 53,306 52,349 51,916 Earnings per common share: Basic $ 9.33 $ 7.37 $ 6.70 Diluted 9.20 7.31 6.62
Common Shares Excluded from Diluted EPS Calculation as They Were Deemed to be Anti-Dilutive	The following table summarizes the weighted average common shares excluded from the diluted EPS calculation due to the antidilutive effect for 2017 , 2016 and 2015 : Year ended December 31, (Shares in thousands) 2017 2016 2015 Stock options 73 272 185 Restricted stock units 1 1 — Total 74 273 185

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share Based Compensation and Related Benefits	In 2017 , 2016 and 2015 , we recorded share-based compensation and related benefits as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Share-based compensation expense $ 36,900 $ 35,494 $ 32,239 Income tax benefit related to share-based compensation expense (12,845 ) (12,505 ) (11,395 ) Capitalized compensation costs 1,071 5,580 2,226
Unrecognized Share Based Compensation Expense	As of December 31, 2017 , unrecognized share-based compensation expense was as follows: (Dollars in thousands) Unrecognized Expense Weighted Average Expected Recognition Period - in Years Stock options $ 9,630 2.59 Restricted stock units 50,530 2.59 Total unrecognized share-based compensation expense $ 60,160
Weighted Average Assumptions and Fair Values Used for Employee Stock Options and Restricted Stock Units	The following weighted average assumptions and fair values were used for our employee stock options and restricted stock units: Equity Incentive Plan Awards 2017 2016 2015 Weighted average expected term of options - in years 4.9 4.8 4.7 Weighted average expected volatility of the Company's underlying common stock 33.7 % 31.7 % 31.3 % Risk-free interest rate 1.81 1.32 1.49 Expected dividend yield — — — Weighted average grant date fair value - stock options $ 57.81 $ 31.17 $ 37.86 Weighted average grant date fair value - restricted stock units 181.23 100.35 129.23
Weighted Average Assumptions and Fair Values Used for ESPP	The following weighted average assumptions and fair values were used for our ESPP: ESPP 2017 2016 2015 Expected term in years 0.5 0.5 0.5 Weighted average expected volatility of the Company's underlying common stock 31.2 % 41.8 % 25.9 % Risk-free interest rate 0.80 0.45 0.12 Expected dividend yield — — — Weighted average grant date fair value $ 41.70 $ 29.16 $ 29.27
Stock Option Information Related to Equity Incentive Plan	The table below provides stock option information related to the 2006 Equity Incentive Plan for the year ended December 31, 2017 : Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life - in Years Aggregate Intrinsic Value of In-The-Money Options Outstanding at December 31, 2016 1,010,557 $ 87.24 Granted 116,995 179.39 Exercised (302,744 ) 71.65 Forfeited (16,759 ) 122.97 Outstanding at December 31, 2017 808,049 105.68 3.69 $ 103,506,420 Vested and expected to vest at December 31, 2017 787,182 104.69 3.64 101,607,636 Exercisable at December 31, 2017 464,685 84.86 2.57 69,197,233
Stock Options Outstanding	The following table summarizes information regarding stock options outstanding and exercisable as of December 31, 2017 : Outstanding Options Exercisable Options Range of Exercise Prices Shares Weighted Average Remaining Contractual Life - in Years Weighted Average Exercise Price Shares Weighted Average Exercise Price $42.79 - 63.62 52,630 0.52 $ 59.22 52,630 $ 59.22 63.63 - 67.77 84,961 1.33 64.37 84,961 64.37 67.78 - 79.77 141,026 2.33 71.11 141,026 71.11 79.78 - 105.14 11,686 3.67 98.17 7,336 96.09 105.15 - 105.84 154,345 5.33 105.18 31,958 105.18 105.85 - 108.59 148,456 3.32 107.96 101,824 107.95 108.60 - 149.65 102,306 4.27 128.65 44,950 128.13 149.66 - 180.62 108,266 6.34 178.15 — — 180.63 - 217.69 4,373 6.80 210.42 — — Total 808,049 3.69 105.68 464,685 84.86
Information for Restricted Stock Units under Equity Incentive Plan	The table below provides information for restricted stock units under the 2006 Equity Incentive Plan for the year ended December 31, 2017 : Shares Weighted Average Grant Date Fair Value Nonvested at December 31, 2016 670,969 $ 106.64 Granted 247,591 181.23 Vested (228,198 ) 102.47 Forfeited (52,695 ) 121.52 Nonvested at December 31, 2017 637,667 135.86
Summary of Information Regarding Stock Option and Restricted Stock Activity	The following table summarizes information regarding stock option and restricted stock unit activity during 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Total intrinsic value of stock options exercised $ 36,173 $ 18,186 $ 27,430 Total grant date fair value of stock options vested 6,094 7,364 21,052 Total intrinsic value of restricted stock vested 40,925 22,966 34,009 Total grant date fair value of restricted stock vested 23,383 19,454 19,428

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments In Variable Interest Entities [Abstract]
Schedule of Variable Interest Entities	The following table presents the carrying amounts and classification of significant variable interests in consolidated and unconsolidated VIEs as of December 31, 2017 and December 31, 2016 : (Dollars in thousands) Consolidated VIEs Unconsolidated VIEs Maximum Exposure to Loss in Unconsolidated VIEs December 31, 2017: Assets: Cash and cash equivalents $ 6,674 $ — $ — Non-marketable and other securities (1) 190,562 346,097 346,097 Accrued interest receivable and other assets 365 — — Total assets $ 197,601 $ 346,097 $ 346,097 Liabilities: Other liabilities (1) 990 100,891 — Total liabilities $ 990 $ 100,891 $ — December 31, 2016: Assets: Cash and cash equivalents $ 11,469 $ — $ — Non-marketable and other securities (1) 196,140 314,810 314,810 Accrued interest receivable and other assets 294 — — Total assets $ 207,903 $ 314,810 $ 314,810 Liabilities: Other liabilities (1) 517 58,095 — Total liabilities $ 517 $ 58,095 $ — (1) Included in our unconsolidated non-marketable and other securities portfolio at December 31, 2017 and December 31, 2016 are investments in qualified affordable housing projects of $174.2 million and $112.4 million , respectively, and related other liabilities consisting of unfunded credit commitments of $100.9 million and $58.1 million , respectively.

Reserves on Deposit with the 39

Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock (Tables)	12 Months Ended
	Dec. 31, 2017
Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock [Abstract]
Average Required Reserve Balances	The tables below provide information on the required reserve balances at the Federal Reserve, as well as shares held at the FHLB and FRB for the years ended and as of December 31, 2017 and 2016 : Year ended December 31, (Dollars in thousands) 2017 2016 Average required reserve balances at FRB San Francisco $ 397,235 $ 370,002
Shares Held at Federal Reserve Bank and Federal Home Loan Bank	December 31, (Dollars in thousands) 2017 2016 FHLB stock holdings $ 18,900 $ 17,250 FRB stock holdings 41,120 40,342

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	12 Months Ended
	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	The following table details our cash and cash equivalents at December 31, 2017 and December 31, 2016 : (Dollars in thousands) December 31, 2017 December 31, 2016 Cash and due from banks (1) $ 2,672,290 $ 2,476,588 Securities purchased under agreements to resell (2) 247,876 64,028 Other short-term investment securities 2,909 5,134 Total cash and cash equivalents $ 2,923,075 $ 2,545,750 (1) At December 31, 2017 and 2016 , $0.6 billion and $1.1 billion , respectively, of our cash and due from banks was deposited at the FRB and was earning interest at the Federal Funds target rate, and interest-earning deposits in other financial institutions were $1.1 billion and $0.7 billion , respectively. (2) At December 31, 2017 and 2016 , securities purchased under agreements to resell were collateralized by U.S. Treasury securities and U.S. agency securities with aggregate fair values of $253 million and $66 million , respectively. None of these securities were sold or repledged as of December 31, 2017 and 2016 .
Securities Purchased Under Agreements to Resell	Additional information regarding our securities purchased under agreements to resell for 2017 and 2016 are as follows: Year Ended December 31, (Dollars in thousands) 2017 2016 Average securities purchased under agreements to resell $ 94,094 $ 90,362 Maximum amount outstanding at any month-end during the year 377,073 316,059

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Major Components of Investment Securities Portfolio	The major components of our AFS investment securities portfolio at December 31, 2017 and 2016 are as follows: December 31, 2017 (Dollars in thousands) Amortized Unrealized Unrealized Carrying Available-for-sale securities, at fair value: U.S. Treasury securities $ 6,865,068 $ 1,113 $ (25,679 ) $ 6,840,502 U.S. agency debentures 1,569,195 3,569 (5,636 ) 1,567,128 Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations—fixed rate 2,292,311 258 (25,534 ) 2,267,035 Agency-issued collateralized mortgage obligations—variable rate 372,481 1,375 (126 ) 373,730 Equity securities 31,953 40,525 (209 ) 72,269 Total available-for-sale securities $ 11,131,008 $ 46,840 $ (57,184 ) $ 11,120,664 December 31, 2016 (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Carrying Value Available-for-sale securities, at fair value: U.S. Treasury securities $ 8,880,358 $ 30,323 $ (1,190 ) $ 8,909,491 U.S. agency debentures 2,065,535 14,443 (1,603 ) 2,078,375 Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations—fixed rate 1,163,017 3,046 (13,398 ) 1,152,665 Agency-issued collateralized mortgage obligations—variable rate 474,238 685 (640 ) 474,283 Equity securities 5,635 748 (786 ) 5,597 Total available-for-sale securities $ 12,588,783 $ 49,245 $ (17,617 ) $ 12,620,411
Summary of Unrealized Losses on Available for Sale Securities	The following tables summarize our unrealized losses on our AFS securities portfolio into categories of less than 12 months, or 12 months or longer as of December 31, 2017 and 2016 : December 31, 2017 Less than 12 months 12 months or longer Total (Dollars in thousands) Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Available-for-sale securities: U.S. Treasury securities $ 5,968,914 $ (23,397 ) $ 323,966 $ (2,282 ) $ 6,292,880 $ (25,679 ) U.S. agency debentures 736,541 (2,289 ) 336,196 (3,347 ) 1,072,737 (5,636 ) Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations—fixed rate 2,193,277 (25,534 ) — — 2,193,277 (25,534 ) Agency-issued collateralized mortgage obligations—variable rate 13,843 (3 ) 53,186 (123 ) 67,029 (126 ) Equity securities 624 (209 ) — — 624 (209 ) Total temporarily impaired securities (1) $ 8,913,199 $ (51,432 ) $ 713,348 $ (5,752 ) $ 9,626,547 $ (57,184 ) (1) As of December 31, 2017 , we identified a total of 268 investments that were in unrealized loss positions, of which 46 investments totaling $713.3 million with unrealized losses of $5.8 million have been in an impaired position for a period of time greater than 12 months. As of December 31, 2017 , we do not intend to sell any of our impaired securities prior to recovery of our adjusted cost basis, and it is more likely than not that we will not be required to sell any of our securities prior to recovery of our adjusted cost basis. Based on our analysis as of December 31, 2017 , we deem all impairments to be temporary, and therefore changes in value for our temporarily impaired securities as of the same date are included in other comprehensive income. Market valuations and impairment analyses on assets in the AFS securities portfolio are reviewed and monitored on a quarterly basis. December 31, 2016 Less than 12 months 12 months or longer Total (Dollars in thousands) Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Available-for-sale securities: U.S. Treasury securities $ 879,255 $ (1,190 ) $ — $ — $ 879,255 $ (1,190 ) U.S. agency debentures 513,198 (1,603 ) — — 513,198 (1,603 ) Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations—fixed rate 635,566 (6,704 ) 227,480 (6,694 ) 863,046 (13,398 ) Agency-issued collateralized mortgage obligations—variable rate 258,325 (613 ) 6,068 (27 ) 264,393 (640 ) Equity securities 3,693 (786 ) — — 3,693 (786 ) Total temporarily impaired securities (1) $ 2,290,037 $ (10,896 ) $ 233,548 $ (6,721 ) $ 2,523,585 $ (17,617 ) (1) As of December 31, 2016 , we identified a total of 174 investments that were in unrealized loss positions, of which 20 investments totaling $233.5 million with unrealized losses of $6.7 million have been in an impaired position for a period of time greater than 12 months.
Summary of Remaining Contractual Principal Maturities and Fully Taxable Equivalent Yields on Securities	The following table summarizes the fixed income securities, carried at fair value, classified as AFS as of December 31, 2017 by the remaining contractual principal maturities. For U.S. Treasury securities and U.S. agency debentures, the expected maturity is the actual contractual maturity of the notes. Expected maturities for mortgage-backed securities may differ significantly from their contractual maturities because mortgage borrowers have the right to prepay outstanding loan obligations with or without penalties. Mortgage-backed securities classified as AFS typically have original contractual maturities from 10 to 30 years whereas expected average lives of these securities tend to be significantly shorter and vary based upon structure and prepayments in lower rate environments. December 31, 2017 (Dollars in thousands) Total One Year After One After Five After U.S. Treasury securities $ 6,840,502 $ 1,967,480 $ 4,873,022 $ — $ — U.S. agency debentures 1,567,128 481,280 1,085,848 — — Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations - fixed rate 2,267,035 — — 88,425 2,178,610 Agency-issued collateralized mortgage obligations - variable rate 373,730 — — — 373,730 Total $ 11,048,395 $ 2,448,760 $ 5,958,870 $ 88,425 $ 2,552,340 The following table summarizes the remaining contractual principal maturities on fixed income investment securities classified as HTM as of December 31, 2017 . For U.S. agency debentures, the expected maturity is the actual contractual maturity of the notes. Expected maturities for mortgage-backed securities may differ significantly from their contractual maturities because mortgage borrowers have the right to prepay outstanding loan obligations with or without penalties. Mortgage-backed securities classified as HTM typically have original contractual maturities from 10 to 30 years whereas expected average lives of these securities tend to be significantly shorter and vary based upon structure and prepayments in lower rate environments. December 31, 2017 Total One Year or Less After One Year to Five Years After Five Years to Ten Years After Ten Years (Dollars in thousands) Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value U.S. agency debentures $ 659,979 $ 661,545 $ — $ — $ 102,496 $ 102,739 $ 557,483 $ 558,806 $ — $ — Residential mortgage-backed securities: Agency-issued mortgage-backed securities 6,304,969 6,266,295 728 723 226,997 225,149 56,380 55,697 6,020,864 5,984,726 Agency-issued collateralized mortgage obligations - fixed rate 2,829,979 2,775,630 — — — — 462,533 451,069 2,367,446 2,324,561 Agency-issued collateralized mortgage obligations - variable rate 255,782 256,481 — — — — — — 255,782 256,481 Agency-issued commercial mortgage-backed securities 1,868,985 1,844,116 — — — — — — 1,868,985 1,844,116 Municipal bonds and notes 743,761 744,213 7,073 7,054 73,054 72,261 233,728 233,257 429,906 431,641 Total $ 12,663,455 $ 12,548,280 $ 7,801 $ 7,777 $ 402,547 $ 400,149 $ 1,310,124 $ 1,298,829 $ 10,942,983 $ 10,841,525
Held-to-maturity Securities	The components of our HTM investment securities portfolio at December 31, 2017 and 2016 are as follows: December 31, 2017 (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Held-to-maturity securities, at cost: U.S. agency debentures (1) $ 659,979 $ 3,167 $ (1,601 ) $ 661,545 Residential mortgage-backed securities: Agency-issued mortgage-backed securities 6,304,969 4,854 (43,528 ) 6,266,295 Agency-issued collateralized mortgage obligations—fixed rate 2,829,979 23 (54,372 ) 2,775,630 Agency-issued collateralized mortgage obligations—variable rate 255,782 733 (34 ) 256,481 Agency-issued commercial mortgage-backed securities 1,868,985 694 (25,563 ) 1,844,116 Municipal bonds and notes 743,761 3,452 (3,000 ) 744,213 Total held-to-maturity securities $ 12,663,455 $ 12,923 $ (128,098 ) $ 12,548,280 (1) Consists of pools of Small Business Investment Company debentures issued and guaranteed by the U.S. Small Business Administration, an independent agency of the United States. December 31, 2016 (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Held-to-maturity securities, at cost: U.S. agency debentures (1) $ 622,445 $ 7,840 $ (1,198 ) $ 629,087 Residential mortgage-backed securities: Agency-issued mortgage-backed securities 2,896,179 6,919 (24,526 ) 2,878,572 Agency-issued collateralized mortgage obligations—fixed rate 3,362,598 788 (31,274 ) 3,332,112 Agency-issued collateralized mortgage obligations—variable rate 312,665 176 (1,339 ) 311,502 Agency-issued commercial mortgage-backed securities 1,151,363 1,237 (7,638 ) 1,144,962 Municipal bonds and notes 81,748 8 (1,853 ) 79,903 Total held-to-maturity securities $ 8,426,998 $ 16,968 $ (67,828 ) $ 8,376,138 (1) Consists of pools of Small Business Investment Company debentures issued and guaranteed by the U.S. Small Business Administration, an independent agency of the United States. The following tables summarize our unrealized losses on our HTM securities portfolio into categories of less than 12 months and 12 months or longer as of December 31, 2017 and 2016 : December 31, 2017 Less than 12 months 12 months or longer (1) Total (Dollars in thousands) Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Fair Value of Investments Unrealized Losses Held-to-maturity securities: U.S. agency debentures $ 104,688 $ (1,601 ) $ — $ — $ 104,688 $ (1,601 ) Residential mortgage-backed securities: Agency-issued mortgage-backed securities 4,270,377 (34,092 ) 408,913 (9,436 ) 4,679,290 (43,528 ) Agency-issued collateralized mortgage obligations—fixed rate 1,011,709 (13,631 ) 1,741,614 (40,741 ) 2,753,323 (54,372 ) Agency-issued collateralized mortgage obligations—variable rate — — 9,812 (34 ) 9,812 (34 ) Agency-issued commercial mortgage-backed securities 979,361 (11,566 ) 773,712 (13,997 ) 1,753,073 (25,563 ) Municipal bonds and notes 344,796 (2,103 ) 32,844 (897 ) 377,640 (3,000 ) Total temporarily impaired securities (1) $ 6,710,931 $ (62,993 ) $ 2,966,895 $ (65,105 ) $ 9,677,826 $ (128,098 ) (1) As of December 31, 2017 , we identified a total of 753 investments that were in unrealized loss positions, of which 237 investments totaling $3.0 billion with unrealized losses of $65.1 million have been in an impaired position for a period of time greater than 12 months. As of December 31, 2017 , we do not intend to sell any of our impaired securities prior to recovery of our adjusted cost basis, and it is more likely than not that we will not be required to sell any of our securities prior to recovery of our adjusted cost basis, which is consistent with our classification of these securities. Based on our analysis as of December 31, 2017 , we deem all impairments to be temporary. Market valuations and impairment analyses on assets in the HTM securities portfolio are reviewed and monitored on a quarterly basis. December 31, 2016 Less than 12 months 12 months or longer (1) Total (Dollars in thousands) Fair Value of Unrealized Fair Value of Unrealized Fair Value of Unrealized Held-to-maturity securities: U.S. agency debentures $ 118,721 $ (1,198 ) $ — $ — $ 118,721 $ (1,198 ) Residential mortgage-backed securities: Agency-issued mortgage-backed securities 1,801,861 (23,558 ) 21,917 (968 ) 1,823,778 (24,526 ) Agency-issued collateralized mortgage obligations—fixed rate 2,729,889 (25,723 ) 228,220 (5,551 ) 2,958,109 (31,274 ) Agency-issued collateralized mortgage obligations—variable rate 251,012 (1,339 ) — — 251,012 (1,339 ) Agency-issued commercial mortgage-backed securities 999,440 (7,494 ) 14,934 (144 ) 1,014,374 (7,638 ) Municipal bonds and notes 42,267 (877 ) 30,586 (976 ) 72,853 (1,853 ) Total temporarily impaired securities (1) $ 5,943,190 $ (60,189 ) $ 295,657 $ (7,639 ) $ 6,238,847 $ (67,828 ) (1) As of December 31, 2016 , we identified a total of 462 investments that were in unrealized loss positions, of which 85 investments totaling $295.7 million with unrealized losses of $7.6 million have been in an impaired position for a period of time greater than 12 months.
Schedule of Nonmarketable and Other Securities	The major components of our non-marketable and other investment securities portfolio at December 31, 2017 and 2016 are as follows: (Dollars in thousands) December 31, 2017 December 31, 2016 Non-marketable and other securities: Non-marketable securities (fair value accounting): Venture capital and private equity fund investments (1) $ 127,192 $ 141,649 Other venture capital investments (2) 919 2,040 Other securities (fair value accounting) (3) 310 753 Non-marketable securities (equity method accounting) (4): Venture capital and private equity fund investments 89,809 82,823 Debt funds 21,183 17,020 Other investments 111,198 123,514 Non-marketable securities (cost method accounting): Venture capital and private equity fund investments (5) 98,548 114,606 Other investments 27,680 27,700 Investments in qualified affordable housing projects, net (6) 174,214 112,447 Total non-marketable and other securities $ 651,053 $ 622,552 (1) The following table shows the amounts of venture capital and private equity fund investments held by the following consolidated funds and our ownership percentage of each fund at December 31, 2017 and 2016 (fair value accounting): December 31, 2017 December 31, 2016 (Dollars in thousands) Amount Ownership % Amount Ownership % Strategic Investors Fund, LP $ 14,673 12.6 % $ 18,459 12.6 % Capital Preferred Return Fund, LP 54,147 20.0 57,627 20.0 Growth Partners, LP 58,372 33.0 59,718 33.0 Other private equity fund (i) — — 5,845 58.2 Total venture capital and private equity fund investments $ 127,192 $ 141,649 (i) At December 31, 2016, we had direct ownership interest of 41.5 percent in one other private equity fund and an indirect ownership interest of 12.6 percent through our ownership interest of Growth Partners, LP and an indirect ownership interest of 4.1 percent through our ownership interest of Capital Preferred Return Fund, LP. On January 3, 2017, such other private equity fund was closed resulting in an immaterial impact on the Company's financial statements. (2) The following table shows the amounts of other venture capital investments held by the following consolidated funds and our ownership percentage of each fund at December 31, 2017 and 2016 (fair value accounting): December 31, 2017 December 31, 2016 (Dollars in thousands) Amount Ownership % Amount Ownership % CP I, LP $ 919 10.7 % $ 2,040 10.7 % Total other venture capital investments $ 919 $ 2,040 (3) Investments classified as other securities (fair value accounting) represent direct equity investments in public companies held by our consolidated funds. (4) The following table shows the carrying value and our ownership percentage of each investment at December 31, 2017 and 2016 (equity method accounting): December 31, 2017 December 31, 2016 (Dollars in thousands) Amount Ownership % Amount Ownership % Venture capital and private equity fund investments: Strategic Investors Fund II, LP $ 6,342 8.6 % $ 7,720 8.6 % Strategic Investors Fund III, LP 18,758 5.9 20,449 5.9 Strategic Investors Fund IV, LP 25,551 5.0 24,530 5.0 Strategic Investors Fund V funds 16,856 Various 12,029 Various CP II, LP (i) 6,700 5.1 7,798 5.1 Other venture capital and private equity fund investments 15,602 Various 10,297 Various Total venture capital and private equity fund investments $ 89,809 $ 82,823 Debt funds: Gold Hill Capital 2008, LP (ii) $ 18,690 15.5 % $ 13,557 15.5 % Other debt funds 2,493 Various 3,463 Various Total debt funds $ 21,183 $ 17,020 Other investments: SPD Silicon Valley Bank Co., Ltd. $ 75,337 50.0 % $ 75,296 50.0 % Other investments 35,861 Various 48,218 Various Total other investments $ 111,198 $ 123,514 (i) Our ownership includes direct ownership of 1.3 percent and indirect ownership interest of 3.8 percent through our investments in Strategic Investors Fund II, LP. (ii) Our ownership includes direct ownership interest of 11.5 percent in the fund and an indirect interest in the fund through our investment in Gold Hill Capital 2008, LLC of 4.0 percent . (5) Represents investments in 235 and 252 funds (primarily venture capital funds) at December 31, 2017 and 2016 , respectively, where our ownership interest is less than five percent of the voting interests of each such fund and in which we do not have the ability to exercise significant influence over the partnerships operating activities and financial policies. The carrying value, and estimated fair value, of these venture capital and private equity fund investments (cost method accounting) was $99 million , and $202 million , respectively, as of December 31, 2017 . The carrying value, and estimated fair value, of the venture capital and private equity fund investments (cost method accounting) was $115 million , and $222 million , respectively, as of December 31, 2016 . (6) The following table presents the balances of our investments in qualified affordable housing projects and related unfunded commitments included as a component of "other liabilities" on our consolidated balance sheets at December 31, 2017 and 2016 : (Dollars in thousands) December 31, 2017 December 31, 2016 Investments in qualified affordable housing projects, net $ 174,214 $ 112,447 Other liabilities 100,891 58,095 The following table presents other information relating to our investments in qualified affordable housing projects for the year ended December 31, 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Tax credits and other tax benefits recognized $ 17,296 $ 15,404 $ 14,375 Amortization expense included in provision for income taxes (i) 17,362 12,145 10,389 (i) All investments are amortized using the proportional amortization method and amortization expense is included in the provision for income taxes. Included in amortization expense for the year ended December 31, 2017 is a one-time cumulative effect adjustment of $3.8 million due to the decrease in value of deductions in the 2018 tax year and going forward, due to the TCJ Act federal corporate income tax rate reduction.
Components of Gains and Losses (Realized and Unrealized) on Investment Securities	The following table presents the components of gains and losses (realized and unrealized) on investment securities in 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Gross gains on investment securities: Available-for-sale securities, at fair value (1) $ 5,113 $ 15,051 $ 2,971 Non-marketable securities (fair value accounting): Venture capital and private equity fund investments 34,093 25,041 32,399 Other venture capital investments 1,114 17 1,512 Other securities (fair value accounting) 991 691 9,180 Non-marketable securities (equity method accounting): Venture capital and private equity fund investments 15,013 10,834 26,415 Debt funds 11,658 1,406 4,111 Other investments 3,181 15,739 2,791 Non-marketable securities (cost method accounting): Venture capital and private equity fund investments 21,718 18,428 25,908 Other investments 4,111 293 2,599 Total gross gains on investment securities 96,992 87,500 107,886 Gross losses on investment securities: Available-for-sale securities, at fair value (1) (10,302 ) (2,856 ) (1,770 ) Non-marketable securities (fair value accounting): Venture capital and private equity fund investments (6,907 ) (19,077 ) (9,210 ) Other venture capital investments (143 ) (38 ) (320 ) Other securities (fair value accounting) (750 ) (781 ) (1,559 ) Non-marketable securities (equity method accounting): Venture capital and private equity fund investments (541 ) (6,764 ) (909 ) Debt funds (2,708 ) (458 ) (774 ) Other investments (9,457 ) (4,857 ) (3,146 ) Non-marketable securities (cost method accounting): Venture capital and private equity fund investments (2) (1,312 ) (591 ) (729 ) Other investments (3) (269 ) (338 ) (24 ) Total gross losses on investment securities (32,389 ) (35,760 ) (18,441 ) Gains on investment securities, net $ 64,603 $ 51,740 $ 89,445 (1) Includes realized gains and losses on sales of AFS securities that are recognized in the income statement. Unrealized gains and losses on AFS securities are recognized in other comprehensive income. The cost basis of AFS securities sold is determined on a specific identification basis. (2) Includes OTTI of $1.3 million from the declines in value for 24 of the 235 investments held at December 31, 2017 , $0.6 million from the declines in value for 26 of the 252 investments held at December 31, 2016 and $0.6 million from the declines in value for 22 of the 267 investments held at December 31, 2015 . We concluded that any declines in value for the remaining investments were temporary, and as such, no OTTI was required to be recognized. (3) No OTTI was recognized for the years ended December 31, 2017 , 2016 , and 2015 , respectively. We concluded that any declines in value for the investments were temporary, and as such, no OTTI was required to be recognized. A summary of gains and losses on investment securities for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Gains on non-marketable and other securities, net $ 69,792 $ 39,545 $ 88,244 (Losses) gains on sales of available-for-sale securities, net (5,189 ) 12,195 1,201 Gains on investment securities, net $ 64,603 $ 51,740 $ 89,445

Loans and Allowance for Loan 42

Loans and Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Loans and Allowance for Loan Losses	The composition of loans, net of unearned income of $148 million and $125 million at December 31, 2017 and 2016 , respectively, is presented in the following table: December 31, (Dollars in thousands) 2017 2016 Commercial loans: Software/internet $ 6,172,531 $ 5,627,031 Hardware 1,193,599 1,180,398 Private equity/venture capital 9,952,377 7,691,148 Life science/healthcare 1,808,827 1,853,004 Premium wine 204,105 200,156 Other 365,724 393,551 Total commercial loans 19,697,163 16,945,288 Real estate secured loans: Premium wine (1) 669,053 678,166 Consumer loans (2) 2,300,506 1,926,968 Other 42,068 43,487 Total real estate secured loans 3,011,627 2,648,621 Construction loans 68,546 64,671 Consumer loans 328,980 241,364 Total loans, net of unearned income (3) $ 23,106,316 $ 19,899,944 (1) Included in our premium wine portfolio are gross construction loans of $100 million and $110 million at December 31, 2017 and 2016 , respectively. (2) Consumer loans secured by real estate at December 31, 2017 and 2016 were comprised of the following: December 31, (Dollars in thousands) 2017 2016 Loans for personal residence $ 1,995,840 $ 1,655,349 Loans to eligible employees 243,118 199,291 Home equity lines of credit 61,548 72,328 Consumer loans secured by real estate $ 2,300,506 $ 1,926,968 (3) Included within our total loan portfolio are credit card loans of $270 million and $224 million at December 31, 2017 and 2016 , respectively.
Composition of Loans, Net of Unearned Income, Broken Out by Portfolio Segment and Class of Financing Receivable	The composition of loans, net of unearned income of $148 million and $125 million at December 31, 2017 and 2016 , respectively, broken out by portfolio segment and class of financing receivable, is as follows: December 31, (Dollars in thousands) 2017 2016 Commercial loans: Software/internet $ 6,172,531 $ 5,627,031 Hardware 1,193,599 1,180,398 Private equity/venture capital 9,952,377 7,691,148 Life science/healthcare 1,808,827 1,853,004 Premium wine 873,158 878,322 Other 476,338 501,709 Total commercial loans 20,476,830 17,731,612 Consumer loans: Real estate secured loans 2,300,506 1,926,968 Other consumer loans 328,980 241,364 Total consumer loans 2,629,486 2,168,332 Total loans, net of unearned income $ 23,106,316 $ 19,899,944
Aging of Gross Loans, Broken out by Portfolio Segment and Class of Financing Receivable	The following table summarizes the aging of our gross loans, broken out by portfolio segment and class of financing receivable as of December 31, 2017 and 2016 : (Dollars in thousands) 30 - 59 Days Past Due 60 - 89 Days Past Due Equal to or Greater Than 90 Days Past Due Total Past Due Current Loans Past Due 90 Days or More Still Accruing Interest December 31, 2017: Commercial loans: Software/internet $ 14,257 $ 6,526 $ 141 $ 20,924 $ 6,101,147 $ 141 Hardware 1,145 77 50 1,272 1,163,278 50 Private equity/venture capital 86,566 38,580 — 125,146 9,835,317 — Life science/healthcare 4,390 191 — 4,581 1,841,692 — Premium wine 418 — — 418 871,074 — Other 445 — — 445 490,292 — Total commercial loans 107,221 45,374 191 152,786 20,302,800 191 Consumer loans: Real estate secured loans 2,164 532 — 2,696 2,292,980 — Other consumer loans 796 — — 796 327,234 — Total consumer loans 2,960 532 — 3,492 2,620,214 — Total gross loans excluding impaired loans 110,181 45,906 191 156,278 22,923,014 191 Impaired loans 1,344 11,902 30,403 43,649 131,212 — Total gross loans $ 111,525 $ 57,808 $ 30,594 $ 199,927 $ 23,054,226 $ 191 December 31, 2016: Commercial loans: Software/internet $ 37,087 $ 1,162 $ 6 $ 38,255 $ 5,507,575 $ 6 Hardware 5,591 36 27 5,654 1,118,065 27 Private equity/venture capital 689 — — 689 7,747,222 — Life science/healthcare 283 551 — 834 1,827,490 — Premium wine 1,003 4 — 1,007 876,185 — Other 34 300 — 334 504,021 — Total commercial loans 44,687 2,053 33 46,773 17,580,558 33 Consumer loans: Real estate secured loans 850 — — 850 1,923,266 — Other consumer loans 1,402 — — 1,402 237,353 — Total consumer loans 2,252 — — 2,252 2,160,619 — Total gross loans excluding impaired loans 46,939 2,053 33 49,025 19,741,177 33 Impaired loans 34,636 3,451 11,180 49,267 185,193 — Total gross loans $ 81,575 $ 5,504 $ 11,213 $ 98,292 $ 19,926,370 $ 33
Impaired Loans and Allowance for Loan Losses, Broken out by Portfolio Segment and Class of Financing Receivable	The following table summarizes our impaired loans as they relate to our allowance for loan losses, broken out by portfolio segment and class of financing receivable for the years ended December 31, 2017 and 2016 : (Dollars in thousands) Impaired loans for which there is a related allowance for loan losses Impaired loans for which there is no related allowance for loan losses Total carrying value of impaired loans Total unpaid principal of impaired loans December 31, 2017: Commercial loans: Software/internet $ 49,645 $ 61,009 $ 110,654 $ 129,006 Hardware 15,637 20,713 36,350 41,721 Private equity/venture capital 658 — 658 984 Life science/healthcare 20,521 1,166 21,687 26,360 Premium wine — 2,877 2,877 2,911 Other 32 — 32 165 Total commercial loans 86,493 85,765 172,258 201,147 Consumer loans: Real estate secured loans 1,331 850 2,181 3,712 Other consumer loans 422 — 422 436 Total consumer loans 1,753 850 2,603 4,148 Total $ 88,246 $ 86,615 $ 174,861 $ 205,295 December 31, 2016: Commercial loans: Software/internet $ 121,658 $ 1,090 $ 122,748 $ 129,648 Hardware 65,395 — 65,395 70,683 Private equity/venture capital — — — — Life science/healthcare 38,361 — 38,361 41,130 Premium wine 3,187 — 3,187 3,187 Other 867 — 867 867 Total commercial loans 229,468 1,090 230,558 245,515 Consumer loans: Real estate secured loans 1,504 — 1,504 2,779 Other consumer loans 2,398 — 2,398 2,398 Total consumer loans 3,902 — 3,902 5,177 Total $ 233,370 $ 1,090 $ 234,460 $ 250,692
Average Impaired Loans, Broken out by Portfolio Segment and Class of Financing Receivable	The following table summarizes our average impaired loans and interest income on impaired loans, broken out by portfolio segment and class of financing receivable during 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) Average impaired loans Interest income on impaired loans 2017 2016 2015 2017 2016 2015 Commercial loans: Software/internet $ 119,557 $ 89,462 $ 63,825 $ 2,263 $ 1,054 $ 344 Hardware 35,022 39,108 8,854 1,061 2,624 574 Private equity/venture capital 556 — — — — — Life science/healthcare 30,842 40,620 18,083 90 155 132 Premium wine 3,249 2,056 1,455 152 28 12 Other 576 3,442 2,758 — 6 8 Total commercial loans 189,802 174,688 94,975 3,566 3,867 1,070 Consumer loans: Real estate secured loans 1,514 588 172 — — — Other consumer loans 1,804 1,136 41 — 17 — Total consumer loans 3,318 1,724 213 — 17 — Total average impaired loans $ 193,120 $ 176,412 $ 95,188 $ 3,566 $ 3,884 $ 1,070
Activity in Allowance for Loan Losses Broken out by Portfolio Segment	The following tables summarize the activity relating to our allowance for loan losses for 2017 , 2016 and 2015 broken out by portfolio segment: Year ended December 31, 2017 (Dollars in thousands) Beginning Balance December 31, 2016 Charge-offs Recoveries Provision for (Reduction of) Loan Losses Foreign Currency Translation Adjustments Ending Balance December 31, 2017 Commercial loans: Software/internet $ 97,388 $ (45,012 ) $ 4,649 $ 38,462 $ 617 $ 96,104 Hardware 31,166 (10,414 ) 487 6,051 324 27,614 Private equity/venture capital 50,299 (323 ) — 31,625 867 82,468 Life science/healthcare 25,446 (8,210 ) 189 7,414 85 24,924 Premium wine 4,115 — — (540 ) (43 ) 3,532 Other 4,768 (1,156 ) 1,850 (1,459 ) (62 ) 3,941 Total commercial loans 213,182 (65,115 ) 7,175 81,553 1,788 238,583 Consumer loans 12,184 (1,567 ) 1,363 4,386 75 16,441 Total allowance for loan losses $ 225,366 $ (66,682 ) $ 8,538 $ 85,939 $ 1,863 $ 255,024 Year ended December 31, 2016 (Dollars in thousands) Beginning Balance December 31, 2015 Charge-offs Recoveries Provision for (Reduction of) Loan Losses Foreign Currency Translation Adjustments Ending Balance December 31, 2016 Commercial loans: Software/internet $ 103,045 $ (68,784 ) $ 7,278 $ 58,350 $ (2,501 ) $ 97,388 Hardware 23,085 (13,233 ) 1,667 20,851 (1,204 ) 31,166 Private equity/venture capital 35,282 — — 15,114 (97 ) 50,299 Life science/healthcare 36,576 (9,693 ) 1,129 (2,543 ) (23 ) 25,446 Premium wine 5,205 — — (1,260 ) 170 4,115 Other 4,252 (5,045 ) 1,880 3,373 308 4,768 Total commercial loans 207,445 (96,755 ) 11,954 93,885 (3,347 ) 213,182 Consumer loans 10,168 (102 ) 258 1,812 48 12,184 Total allowance for loan losses $ 217,613 $ (96,857 ) $ 12,212 $ 95,697 $ (3,299 ) $ 225,366 Year ended December 31, 2015 Beginning Balance December 31, 2014 Charge-offs Recoveries Provision for (Reduction of) Loan Losses Foreign Currency Translation Adjustments Ending Balance December 31, 2015 Commercial loans: Software/internet $ 80,981 $ (33,246 ) $ 1,621 $ 53,696 $ (7 ) $ 103,045 Hardware 25,860 (5,145 ) 3,332 (1,035 ) 73 23,085 Private equity/venture capital 27,997 — — 7,391 (106 ) 35,282 Life science/healthcare 15,208 (7,291 ) 277 28,400 (18 ) 36,576 Premium wine 4,473 — 7 725 — 5,205 Other 3,253 (4,990 ) 809 5,736 (556 ) 4,252 Total commercial loans 157,772 (50,672 ) 6,046 94,913 (614 ) 207,445 Consumer loans 7,587 (296 ) 163 2,716 (2 ) 10,168 Total allowance for loan losses $ 165,359 $ (50,968 ) $ 6,209 $ 97,629 $ (616 ) $ 217,613
Allowance for Unfunded Commitments [Table Text Block]	The following table summarizes the activity relating to our allowance for unfunded credit commitments for 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Allowance for unfunded credit commitments, beginning balance $ 45,265 $ 34,415 $ 36,419 Provision for (reduction of) unfunded credit commitments 6,365 10,982 (1,946 ) Foreign currency translation adjustments 140 (132 ) (58 ) Allowance for unfunded credit commitments, ending balance (1) $ 51,770 $ 45,265 $ 34,415 (1) See Note 19—“Off-Balance Sheet Arrangements, Guarantees and Other Commitments” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report for additional disclosures related to our commitments to extend credit.
Allowance for Loan Losses Individually and Collectively Evaluated for Impairment	The following table summarizes the allowance for loan losses individually and collectively evaluated for impairment as of December 31, 2017 and 2016 , broken out by portfolio segment: December 31, 2017 December 31, 2016 Individually Evaluated for Impairment Collectively Evaluated for Impairment Individually Evaluated for Impairment Collectively Evaluated for Impairment (Dollars in thousands) Allowance for loan losses Recorded investment in loans Allowance for loan losses Recorded investment in loans Allowance for loan losses Recorded investment in loans Allowance for loan losses Recorded investment in loans Commercial loans: Software/internet $ 23,088 $ 110,654 $ 73,016 $ 6,061,877 $ 28,245 $ 122,748 $ 69,143 $ 5,504,283 Hardware 8,450 36,350 19,164 1,157,249 9,995 65,395 21,171 1,115,003 Private equity/venture capital 330 658 82,138 9,951,719 — — 50,299 7,691,148 Life science/healthcare 9,315 21,687 15,609 1,787,140 8,709 38,361 16,737 1,814,643 Premium wine — 2,877 3,532 870,281 520 3,187 3,595 875,135 Other 32 32 3,909 476,306 233 867 4,535 500,842 Total commercial loans 41,215 172,258 197,368 20,304,572 47,702 230,558 165,480 17,501,054 Total consumer loans 578 2,603 15,863 2,626,883 1,123 3,902 11,061 2,164,430 Total $ 41,793 $ 174,861 $ 213,231 $ 22,931,455 $ 48,825 $ 234,460 $ 176,541 $ 19,665,484
Credit Quality Indicators, Broken out by Portfolio Segment and Class of Financing Receivables	The following table summarizes the credit quality indicators, broken out by portfolio segment and class of financing receivables as of December 31, 2017 and 2016 : (Dollars in thousands) Pass Performing (Criticized) Performing Impaired (Criticized) Nonperforming Impaired (Nonaccrual) Total December 31, 2017: Commercial loans: Software/internet $ 5,655,739 $ 466,332 $ 31,794 $ 78,860 $ 6,232,725 Hardware 1,112,574 51,976 20,165 16,185 1,200,900 Private equity/venture capital 9,955,082 5,381 — 658 9,961,121 Life science/healthcare 1,720,613 125,660 1,167 20,520 1,867,960 Premium wine 834,537 36,955 2,476 401 874,369 Other 469,721 21,016 — 32 490,769 Total commercial loans 19,748,266 707,320 55,602 116,656 20,627,844 Consumer loans: Real estate secured loans 2,282,375 13,301 — 2,181 2,297,857 Other consumer loans 326,851 1,179 — 422 328,452 Total consumer loans 2,609,226 14,480 — 2,603 2,626,309 Total gross loans $ 22,357,492 $ 721,800 $ 55,602 $ 119,259 $ 23,254,153 December 31, 2016: Commercial loans: Software/internet $ 4,924,923 $ 620,907 $ 46,143 $ 76,605 $ 5,668,578 Hardware 985,889 137,830 58,814 6,581 1,189,114 Private equity/venture capital 7,747,317 594 — — 7,747,911 Life science/healthcare 1,707,499 120,825 6,578 31,783 1,866,685 Premium wine 865,354 11,838 2,696 491 880,379 Other 480,845 23,510 464 403 505,222 Total commercial loans 16,711,827 915,504 114,695 115,863 17,857,889 Consumer loans: Real estate secured loans 1,914,512 9,604 — 1,504 1,925,620 Other consumer loans 238,256 499 786 1,612 241,153 Total consumer loans 2,152,768 10,103 786 3,116 2,166,773 Total gross loans $ 18,864,595 $ 925,607 $ 115,481 $ 118,979 $ 20,024,662
Summary of Loans Modified in Troubled Debt Restructurings ("TDRs") by Portfolio Segment and Class of Financing Receivables	The following table summarizes our loans modified in TDRs, broken out by portfolio segment and class of financing receivables at December 31, 2017 and 2016 : December 31, (Dollars in thousands) 2017 2016 Loans modified in TDRs: Commercial loans: Software/internet $ 73,455 $ 52,646 Hardware 51,132 14,870 Private equity/venture capital 350 — Life science/healthcare 19,235 24,176 Premium wine 3,198 3,194 Other — 387 Total commercial loans 147,370 95,273 Consumer loans: Other consumer loans 423 786 Total loans modified in TDRs $ 147,793 $ 96,059
Recorded Investment in Loans Modified in TDRs	The following table summarizes the recorded investment in loans modified in TDRs, broken out by portfolio segment and class of financing receivable, for modifications made during 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Loans modified in TDRs during the period: Commercial loans: Software/internet $ 42,184 $ 23,574 $ 56,790 Hardware 51,132 14,870 286 Private equity/venture capital 350 — — Life science/healthcare — 1,638 51,878 Premium wine 177 677 898 Other — — 519 Total commercial loans 93,843 40,759 110,371 Consumer loans: Other consumer loans — 786 — Total loans modified in TDRs during the period (1) $ 93,843 $ 41,545 $ 110,371 (1) During 2017 , we had $3.0 million of partial charge-offs on loans classified as TDRs. We had $3.6 million of partial charge-offs in 2016 and $23.5 million of partial charge-offs in 2015.
Recorded Investment in Loans Modified in TDRs within Previous 12 months Subsequently Defaulted	The following table summarizes the recorded investment in loans modified in TDRs within the previous 12 months that subsequently defaulted during their respective periods, broken out by portfolio segment and class of financing receivable, during 2017 , 2016 and 2015 : December 31, (Dollars in thousands) 2017 (1) 2016 2015 TDRs modified within the previous 12 months that defaulted during the period: Commercial loans: Software/internet $ — $ — $ 16,804 Hardware — 134 286 Premium wine — 491 — Life science/healthcare — — 943 Total commercial loans — 625 18,033 Consumer loans: Other consumer loans — 786 — Total TDRs modified within the previous 12 months that defaulted in the period $ — $ 1,411 $ 18,033

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Components of Premises and Equipment	Premises and equipment at December 31, 2017 and 2016 consisted of the following: December 31, (Dollars in thousands) 2017 2016 Computer software $ 203,359 $ 189,867 Computer hardware 63,881 56,215 Leasehold improvements 89,225 70,909 Furniture and equipment 38,146 31,886 Total 394,611 348,877 Accumulated depreciation and amortization (265,929 ) (228,194 ) Premises and equipment, net $ 128,682 $ 120,683

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Composition of Deposits	The following table presents the composition of our deposits at December 31, 2017 and 2016 : December 31, (Dollars in thousands) 2017 2016 Noninterest-bearing demand $ 36,655,497 $ 31,975,457 Interest bearing checking and savings accounts 556,121 375,710 Money market 5,975,220 5,331,054 Money market deposits in foreign offices 111,201 107,657 Sweep deposits in foreign offices 908,890 1,133,872 Time 47,146 56,118 Total deposits $ 44,254,075 $ 38,979,868

Short-Term Borrowings and Lon45

Short-Term Borrowings and Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Outstanding Short Term Borrowings and Long Term Debt	The following table represents outstanding short-term borrowings and long-term debt at December 31, 2017 and 2016 : Carrying Value (Dollars in thousands) Maturity Principal value at December 31, 2017 December 31, December 31, Short-term borrowings: Short-term FHLB advances January 2, 2018 $ 700,000 $ 700,000 $ 500,000 Federal funds purchased January 2, 2018 330,000 330,000 — Other short-term borrowings (1) 3,730 3,730 12,668 Total short-term borrowings $ 1,033,730 $ 512,668 Long-term debt: 3.50% Senior Notes January 29, 2025 $ 350,000 $ 347,303 $ 346,979 5.375% Senior Notes September 15, 2020 350,000 348,189 347,586 6.05% Subordinated Notes (2) — — 46,646 7.0% Junior Subordinated Debentures (3) — — 54,493 Total long-term debt $ 695,492 $ 795,704 (1) Represents cash collateral received from certain counterparties in relation to market value exposures of derivative contracts in our favor. (2) Our 6.05% Subordinated Notes were repaid on June 1, 2017 and the interest rate swap agreement related to this issuance was terminated upon repayment of the 6.05% Subordinated Notes. At December 31, 2016, included in the carrying value of our 6.05% Subordinated Notes were $0.8 million related to hedge accounting associated with the notes. (3) On December 21, 2017, we redeemed in full the outstanding aggregate principal amount of $51.5 million of our 7.0% Junior Subordinated Debentures due October 15, 2033, relating to our 7.0% Cumulative Trust Preferred Securities issued by SVB Capital II.
Aggregate Annual Maturities of Long-Term Debt Obligations	The aggregate annual maturities of long-term debt obligations as of December 31, 2017 are as follows: Year ended December 31, (Dollars in thousands): Amount 2018 $ — 2019 — 2020 348,189 2021 — 2022 — 2023 and thereafter 347,303 Total $ 695,492

Derivative Financial Instrume46

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Total Notional or Contractual Amounts, Fair Value, Collateral and Net Exposure of Derivative Financial Instruments	The total notional or contractual amounts, fair value, collateral and net exposure of our derivative financial instruments at December 31, 2017 and 2016 were as follows: December 31, 2017 December 31, 2016 (Dollars in thousands) Balance Sheet Location Notional or Contractual Amount Fair Value Collateral (1) Net Exposure (2) Notional or Contractual Amount Fair Value Collateral (1) Net Exposure (2) Derivatives designated as hedging instruments: Interest rate risks: Interest rate swaps Other assets $ — $ — $ — $ — $ 45,964 $ 810 $ 89 $ 721 Derivatives not designated as hedging instruments: Currency exchange risks: Foreign exchange forwards Other assets 50,889 414 39 375 219,950 3,057 — 3,057 Foreign exchange forwards Other liabilities 425,055 (5,201 ) — (5,201 ) 54,338 (968 ) — (968 ) Net exposure (4,787 ) 39 (4,826 ) 2,089 — 2,089 Other derivative instruments: Equity warrant assets Other assets 211,253 123,763 — 123,763 211,434 131,123 — 131,123 Other derivatives: Client foreign exchange forwards Other assets 2,203,643 95,035 3,691 91,344 1,251,308 54,587 12,579 42,008 Client foreign exchange forwards Other liabilities 2,092,207 (90,253 ) — (90,253 ) 1,068,991 (43,317 ) — (43,317 ) Client foreign currency options Other assets 102,678 1,187 — 1,187 775,000 10,383 — 10,383 Client foreign currency options Other liabilities 102,678 (1,187 ) — (1,187 ) 775,000 (10,383 ) — (10,383 ) Client interest rate derivatives Other assets 726,984 11,753 — 11,753 583,511 10,110 — 10,110 Client interest rate derivatives Other liabilities 782,586 (11,940 ) — (11,940 ) 627,639 (9,770 ) — (9,770 ) Net exposure 4,595 3,691 904 11,610 12,579 (969 ) Net $ 123,571 $ 3,730 $ 119,841 $ 145,632 $ 12,668 $ 132,964 (1) Cash collateral received from our counterparties in relation to market value exposures of derivative contracts in our favor is recorded as a component of “short-term borrowings” on our consolidated balance sheets. (2) Net exposure for contracts in a gain position reflects the replacement cost in the event of nonperformance by all such counterparties. The credit ratings of our institutional counterparties as of December 31, 2017 remain at investment grade or higher and there were no material changes in their credit ratings for the year ended December 31, 2017.
Summary of Derivative Activity and Related Impact on Consolidated Statements of Income	A summary of our derivative activity and the related impact on our consolidated statements of income for 2017 , 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) Statement of income location 2017 2016 2015 Derivatives designated as hedging instruments: Interest rate risks: Net cash benefit associated with interest rate swaps Interest expense—borrowings $ 1,053 $ 2,341 $ 2,526 Changes in fair value of interest rate swaps Other noninterest income (7 ) (35 ) (20 ) Net gains associated with interest rate risk derivatives $ 1,046 $ 2,306 $ 2,506 Derivatives not designated as hedging instruments: Currency exchange risks: Gains (losses) on revaluations of internal foreign currency instruments, net Other noninterest income $ 33,161 $ (16,676 ) $ (12,735 ) (Losses) gains on internal foreign exchange forward contracts, net Other noninterest income (32,286 ) 16,136 12,377 Net gains (losses) associated with internal currency risk $ 875 $ (540 ) $ (358 ) Other derivative instruments: Gains on revaluations of client foreign currency instruments, net Other noninterest income $ 10,882 $ 4,215 $ 115 (Losses) gains on client foreign exchange forward contracts, net Other noninterest income (9,969 ) (5,674 ) 694 Net gains (losses) associated with client currency risk $ 913 $ (1,459 ) $ 809 Net gains on equity warrant assets Gains on equity warrant assets, net $ 54,555 $ 37,892 $ 70,963 Net (losses) gains on other derivatives Other noninterest income $ (564 ) $ 262 $ (209 )
Offsetting Assets	The following table summarizes our assets subject to enforceable master netting arrangements as of December 31, 2017 and 2016 : (Dollars in thousands) Gross Amounts of Recognized Assets Gross Amounts offset in the Statement of Financial Position Net Amounts of Assets Presented in the Statement of Financial Position Gross Amounts Not Offset in the Statement of Financial Position But Subject to Master Netting Arrangements Net Amount Financial Instruments Cash Collateral Received December 31, 2017: Derivative Assets: Interest rate swaps $ — $ — $ — $ — $ — $ — Foreign exchange forwards 95,449 — 95,449 (14,456 ) (3,730 ) 77,263 Foreign currency options 1,187 — 1,187 (557 ) — 630 Client interest rate derivatives 11,753 — 11,753 (11,741 ) — 12 Total derivative assets: 108,389 — 108,389 (26,754 ) (3,730 ) 77,905 Reverse repurchase, securities borrowing, and similar arrangements 247,876 — 247,876 (247,876 ) — — Total $ 356,265 $ — $ 356,265 $ (274,630 ) $ (3,730 ) $ 77,905 December 31, 2016: Derivative Assets: Interest rate swaps $ 810 $ — $ 810 $ (721 ) $ (89 ) $ — Foreign exchange forwards 57,644 — 57,644 (22,738 ) (12,579 ) 22,327 Foreign currency options 10,383 — 10,383 (8,806 ) — 1,577 Client interest rate derivatives 10,110 — 10,110 (10,091 ) — 19 Total derivative assets: 78,947 — 78,947 (42,356 ) (12,668 ) 23,923 Reverse repurchase, securities borrowing, and similar arrangements 64,028 — 64,028 (64,028 ) — — Total $ 142,975 $ — $ 142,975 $ (106,384 ) $ (12,668 ) $ 23,923
Offsetting Liabilities	The following table summarizes our liabilities subject to enforceable master netting arrangements as of December 31, 2017 and 2016 : (Dollars in thousands) Gross Amounts of Recognized Liabilities Gross Amounts offset in the Statement of Financial Position Net Amounts of Liabilities Presented in the Statement of Financial Position Gross Amounts Not Offset in the Statement of Financial Position But Subject to Master Netting Arrangements Net Amount Financial Instruments Cash Collateral Pledged December 31, 2017: Derivative Liabilities: Foreign exchange forwards $ 95,454 $ — $ 95,454 $ (80,107 ) $ — $ 15,347 Foreign currency options 1,187 — 1,187 (631 ) — 556 Client interest rate derivatives 11,940 — 11,940 (11,924 ) — 16 Total derivative liabilities: 108,581 — 108,581 (92,662 ) — 15,919 Repurchase, securities lending, and similar arrangements — — — — — — Total $ 108,581 $ — $ 108,581 $ (92,662 ) $ — $ 15,919 December 31, 2016: Derivative Liabilities: Foreign exchange forwards $ 44,285 $ — $ 44,285 $ (17,964 ) $ — $ 26,321 Foreign currency options 10,383 — 10,383 (1,585 ) — 8,798 Client interest rate derivatives 9,770 — 9,770 (9,770 ) — — Total derivative liabilities: 64,438 — 64,438 (29,319 ) — 35,119 Repurchase, securities lending, and similar arrangements — — — — — — Total $ 64,438 $ — $ 64,438 $ (29,319 ) $ — $ 35,119

Noninterest Income (Tables)

Noninterest Income (Tables)	12 Months Ended
	Dec. 31, 2017
Other Income and Expenses [Abstract]
Summary of noninterest income	For the year ended December 31, 2017, noninterest income was $557.2 million , compared to $456.6 million and $472.8 million , for the comparable 2016 and 2015 periods. Year ended December 31, (Dollars in thousands) 2017 2016 2015 Noninterest income: Gains on investment securities, net $ 64,603 $ 51,740 $ 89,445 Gains on equity warrant assets, net 54,555 37,892 70,963 Foreign exchange fees 115,760 104,183 87,007 Credit card fees 76,543 68,205 56,657 Deposit service charges 58,715 52,524 46,683 Client investment fees 56,136 32,219 21,610 Lending related fees 43,265 33,395 32,536 Letters of credit and standby letters of credit fees 28,544 25,644 20,889 Other 59,110 50,750 47,004 Total noninterest income $ 557,231 $ 456,552 $ 472,794
Components of Gains and Losses (Realized and Unrealized) on Investment Securities	The following table presents the components of gains and losses (realized and unrealized) on investment securities in 2017 , 2016 and 2015 : Year ended December 31, (Dollars in thousands) 2017 2016 2015 Gross gains on investment securities: Available-for-sale securities, at fair value (1) $ 5,113 $ 15,051 $ 2,971 Non-marketable securities (fair value accounting): Venture capital and private equity fund investments 34,093 25,041 32,399 Other venture capital investments 1,114 17 1,512 Other securities (fair value accounting) 991 691 9,180 Non-marketable securities (equity method accounting): Venture capital and private equity fund investments 15,013 10,834 26,415 Debt funds 11,658 1,406 4,111 Other investments 3,181 15,739 2,791 Non-marketable securities (cost method accounting): Venture capital and private equity fund investments 21,718 18,428 25,908 Other investments 4,111 293 2,599 Total gross gains on investment securities 96,992 87,500 107,886 Gross losses on investment securities: Available-for-sale securities, at fair value (1) (10,302 ) (2,856 ) (1,770 ) Non-marketable securities (fair value accounting): Venture capital and private equity fund investments (6,907 ) (19,077 ) (9,210 ) Other venture capital investments (143 ) (38 ) (320 ) Other securities (fair value accounting) (750 ) (781 ) (1,559 ) Non-marketable securities (equity method accounting): Venture capital and private equity fund investments (541 ) (6,764 ) (909 ) Debt funds (2,708 ) (458 ) (774 ) Other investments (9,457 ) (4,857 ) (3,146 ) Non-marketable securities (cost method accounting): Venture capital and private equity fund investments (2) (1,312 ) (591 ) (729 ) Other investments (3) (269 ) (338 ) (24 ) Total gross losses on investment securities (32,389 ) (35,760 ) (18,441 ) Gains on investment securities, net $ 64,603 $ 51,740 $ 89,445 (1) Includes realized gains and losses on sales of AFS securities that are recognized in the income statement. Unrealized gains and losses on AFS securities are recognized in other comprehensive income. The cost basis of AFS securities sold is determined on a specific identification basis. (2) Includes OTTI of $1.3 million from the declines in value for 24 of the 235 investments held at December 31, 2017 , $0.6 million from the declines in value for 26 of the 252 investments held at December 31, 2016 and $0.6 million from the declines in value for 22 of the 267 investments held at December 31, 2015 . We concluded that any declines in value for the remaining investments were temporary, and as such, no OTTI was required to be recognized. (3) No OTTI was recognized for the years ended December 31, 2017 , 2016 , and 2015 , respectively. We concluded that any declines in value for the investments were temporary, and as such, no OTTI was required to be recognized. A summary of gains and losses on investment securities for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Gains on non-marketable and other securities, net $ 69,792 $ 39,545 $ 88,244 (Losses) gains on sales of available-for-sale securities, net (5,189 ) 12,195 1,201 Gains on investment securities, net $ 64,603 $ 51,740 $ 89,445
Components of Gains on Equity Warrant Assets	A summary of gains on equity warrant assets, net, for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Equity warrant assets: Gains on exercises, net $ 48,275 $ 31,197 $ 41,455 Cancellations and expirations (4,422 ) (3,015 ) (1,040 ) Changes in fair value, net 10,702 9,710 30,548 Net gains on equity warrant assets $ 54,555 $ 37,892 $ 70,963
Components of Foreign Exchange Fees	A summary of foreign exchange fee income by instrument type for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Foreign exchange fees by instrument type: Spot contract commissions $ 104,344 $ 89,354 $ 80,564 Forward contract commissions 10,934 14,004 6,414 Option premium fees 482 825 29 Total foreign exchange fees $ 115,760 $ 104,183 $ 87,007
Components of Credit Card Fees	A summary of credit card fees by instrument type for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Credit card fees by instrument type: Card interchange fees, net $ 60,224 $ 51,513 $ 46,185 Merchant service fees 11,584 12,783 7,346 Card service fees 4,735 3,909 3,126 Total credit card fees $ 76,543 $ 68,205 $ 56,657
Components of Asset Management Fees	A summary of client investment fees by instrument type for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Client investment fees by type: Sweep money market fees $ 28,485 $ 15,147 $ 9,347 Asset management fees 16,831 15,389 12,263 Client directed investment fees 10,820 1,683 — Total client investment fees $ 56,136 $ 32,219 $ 21,610
Components of Lending Related Fees	A summary of lending related fees by instrument type for 2017, 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Lending related fees by instrument type: Unused commitment fees $ 34,110 $ 25,654 $ 24,025 Other 9,155 7,741 8,511 Total lending related fees $ 43,265 $ 33,395 $ 32,536
Summary of Other Noninterest Income	A summary of other noninterest income by instrument type for 2017 , 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Fund management fees $ 21,214 $ 19,195 $ 15,941 Valuation fee income 3,860 7,962 8,767 Gains on revaluation of client foreign currency instruments, net (1) 10,882 4,215 115 (Losses) gains on client foreign exchange forward contracts, net (1) (9,969 ) (5,674 ) 694 Gains (losses) on revaluation of internal foreign currency instruments, net (2) 33,161 (16,676 ) (12,735 ) (Losses) gains on internal foreign exchange forward contracts, net (2) (32,286 ) 16,136 12,377 Other service revenue 32,248 25,592 21,845 Total other noninterest income $ 59,110 $ 50,750 $ 47,004 (1) Represents the net revaluation of client foreign currency denominated financial instruments. We enter into client foreign exchange forward contracts to economically reduce our foreign exchange exposure related to client foreign currency denominated financial instruments. (2) Represents the net revaluation of foreign currency denominated financial instruments issued and held by us, primarily loans, deposits and cash. We enter into internal foreign exchange forward contracts to economically reduce our foreign exchange exposure related to these foreign currency denominated financial instruments issued and held by us.

Other Noninterest Expense (Tabl

Other Noninterest Expense (Tables)	12 Months Ended
	Dec. 31, 2017
Other noninterest expense [Abstract]
Other Non Interest Expense	Other Noninterest Expense A summary of other noninterest expense for 2017 , 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Lending and other client related processing costs $ 23,768 $ 19,867 $ 15,944 Telephone 10,647 9,793 9,398 Data processing services 10,251 9,014 7,316 Dues and publications 3,263 2,828 2,476 Postage and supplies 2,797 2,851 3,154 Other 21,419 17,890 19,999 Total other noninterest expense $ 72,145 $ 62,243 $ 58,287

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Components of Provision for Income Taxes	The components of our provision for income taxes for 2017 , 2016 and 2015 were as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Current provision: Federal $ 263,231 $ 195,249 $ 191,194 State 67,046 59,319 50,815 Deferred expense (benefit): Federal 24,654 (3,560 ) (11,270 ) State 532 (675 ) (1,985 ) Income tax expense $ 355,463 $ 250,333 $ 228,754
Reconciliation between Federal Statutory Income Tax Rate and Effective Income Tax Rate	Our effective tax rate is calculated by dividing income tax expense by the sum of income before income tax expense and the net income attributable to noncontrolling interests. The reconciliation between the federal statutory income tax rate and our effective income tax rate for 2017 , 2016 and 2015 , is as follows: December 31, (Dollars in thousands) 2017 2016 2015 Federal statutory income tax rate 35.0 % 35.0 % 35.0 % State income taxes, net of the federal tax effect 5.8 5.9 5.7 Net deferred tax assets revaluation (TCJ Act) 4.3 — — Meals and entertainment 0.3 0.4 0.3 Disallowed officer's compensation 0.1 0.1 0.3 Share-based compensation expense on incentive stock options and ESPP (2.1 ) — — Qualified affordable housing project tax credits (0.4 ) (0.5 ) (0.5 ) Tax-exempt interest income (0.3 ) (0.2 ) (0.2 ) Valuation allowance benefit — (0.3 ) (0.4 ) Other, net (0.7 ) (0.9 ) (0.3 ) Effective income tax rate 42.0 % 39.5 % 39.9 %
Deferred Tax Assets (Liabilities)	Deferred tax assets and liabilities at December 31, 2017 and 2016 , consisted of the following: December 31, (Dollars in thousands) 2017 2016 Deferred tax assets: Allowance for loan losses $ 84,812 $ 110,248 Net unrealized losses on AFS debt securities 12,404 — Share-based compensation expense 9,418 15,498 State income taxes 9,186 12,682 Accrued compensation 8,336 6,799 Deferred rent 8,169 10,050 Other accruals 7,165 20,502 Net operating loss 2,300 4,116 Loan fee income and costs 1,189 8,266 Other 3,639 2,168 Deferred tax assets 146,618 190,329 Valuation allowance (2,624 ) (4,440 ) Net deferred tax assets after valuation allowance 143,994 185,889 Deferred tax liabilities: Derivative equity warrant assets (29,127 ) (36,406 ) Change in accounting method (section 481(a)) (15,953 ) (35,262 ) Net unrealized gains on AFS equity securities (11,145 ) — Non-marketable and other securities (10,724 ) (6,075 ) Premises and equipment and other intangibles (9,223 ) (11,956 ) Net unrealized gains on AFS debt securities — (17,970 ) Other (3,977 ) (6,380 ) Deferred tax liabilities (80,149 ) (114,049 ) Net deferred tax assets $ 63,845 $ 71,840
Changes in Unrecognized Tax Benefit (Including Interest and Penalties)	A summary of changes in our unrecognized tax benefit (including interest and penalties) for December 31, 2017, 2016 and 2015 is as follows: (Dollars in thousands) Reconciliation of Unrecognized Tax Benefit Interest & Penalties Total Balance at December 31, 2014 $ 3,397 $ 100 $ 3,497 Additions for tax positions for current year 1,208 — 1,208 Additions for tax positions for prior years — 228 228 Reduction for tax positions for prior years (1,228 ) (22 ) (1,250 ) Lapse of the applicable statute of limitations (20 ) (5 ) (25 ) Balance at December 31, 2015 $ 3,357 $ 301 $ 3,658 Additions for tax positions for current year 793 — 793 Additions for tax positions for prior years 1,427 166 1,593 Reduction for tax positions for prior years (271 ) (16 ) (287 ) Lapse of the applicable statute of limitations (37 ) (9 ) (46 ) Balance at December 31, 2016 $ 5,269 $ 442 $ 5,711 Additions for tax positions for current year 3,141 — 3,141 Additions for tax positions for prior years 3,378 754 4,132 Reduction for tax positions for prior years (223 ) (1 ) (224 ) Lapse of the applicable statute of limitations (60 ) (17 ) (77 ) Balance at December 31, 2017 $ 11,505 $ 1,178 $ 12,683

Employee Compensation and Ben50

Employee Compensation and Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Expenses Incurred under Certain Employee Compensation and Benefit Plans	A summary of expenses incurred under certain employee compensation and benefit plans for 2017 , 2016 and 2015 is as follows: Year ended December 31, (Dollars in thousands) 2017 2016 2015 Incentive Compensation Plan $ 125,584 $ 96,892 $ 97,565 Direct Drive Incentive Compensation Plan 18,721 21,174 21,930 Retention Program 1,317 1,475 1,996 Warrant Incentive Plan 15,386 4,954 9,110 Deferred Compensation Plan 203 1,318 2,404 SVBFG 401(k) Plan 17,860 16,078 13,809 SVBFG ESOP 4,719 3,159 8,585

Off-Balance Sheet Arrangement51

Off-Balance Sheet Arrangements, Guarantees and Other Commitments (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure Off Balance Sheet Arrangements Guarantees And Other Commitments Additional Information [Abstract]
Minimum Future Payments under Noncancelable Operating Leases	The following table presents minimum future payments under noncancelable operating leases as of December 31, 2017 : Year ended December 31, (Dollars in thousands) Amount 2018 $ 35,627 2019 35,545 2020 32,117 2021 31,451 2022 27,501 2023 and thereafter 64,234 Net minimum operating lease payments $ 226,475
Summary Information Related to Commitments to Extend Credit (Excluding Letters of Credit)	The following table summarizes information related to our commitments to extend credit at December 31, 2017 and 2016 , respectively: December 31, (Dollars in thousands) 2017 2016 Loan commitments available for funding: (1) Fixed interest rate commitments $ 1,478,157 $ 1,475,179 Variable interest rate commitments 14,034,169 13,572,161 Total loan commitments available for funding 15,512,326 15,047,340 Commercial and standby letters of credit (2) 1,950,211 1,695,856 Total unfunded credit commitments $ 17,462,537 $ 16,743,196 Commitments unavailable for funding (3) $ 2,117,057 $ 1,719,524 Allowance for unfunded credit commitments (4) 51,770 45,265 (1) Represents commitments which are available for funding, due to clients meeting all collateral, compliance and financial covenants required under loan commitment agreements. (2) See below for additional information on our commercial and standby letters of credit. (3) Represents commitments which are currently unavailable for funding due to clients failing to meet all collateral, compliance and financial covenants under loan commitment agreements. (4) Our allowance for unfunded credit commitments includes an allowance for both our unfunded loan commitments and our letters of credit.
Summary of Commercial and Standby Letters of Credit	The table below summarizes our commercial and standby letters of credit at December 31, 2017 . The maximum potential amount of future payments represents the amount that could be remitted under letters of credit if there were a total default by the guaranteed parties, without consideration of possible recoveries under recourse provisions or from the collateral held or pledged. (Dollars in thousands) Expires In One Year or Less Expires After One Year Total Amount Outstanding Maximum Amount of Future Payments Financial standby letters of credit $ 1,765,857 $ 60,819 $ 1,826,676 $ 1,826,676 Performance standby letters of credit 94,519 11,105 105,624 105,624 Commercial letters of credit 17,911 — 17,911 17,911 Total $ 1,878,287 $ 71,924 $ 1,950,211 $ 1,950,211
Total Capital Commitments, Unfunded Capital Commitments, and Ownership in Each Fund	The following table details our total capital commitments, unfunded capital commitments, and our ownership percentage in each fund at December 31, 2017 : (Dollars in thousands) SVBFG Capital Commitments SVBFG Unfunded Commitments SVBFG Ownership of each Fund (3) CP I, LP $ 6,000 $ 270 10.7 % CP II, LP (1) 1,200 162 5.1 Shanghai Yangpu Venture Capital Fund (LP) 891 — 6.8 Strategic Investors Fund, LP 15,300 688 12.6 Strategic Investors Fund II, LP 15,000 1,050 8.6 Strategic Investors Fund III, LP 15,000 1,275 5.9 Strategic Investors Fund IV, LP 12,239 2,325 5.0 Strategic Investors Fund V funds 515 131 Various Capital Preferred Return Fund, LP 12,688 — 20.0 Growth Partners, LP 24,670 1,340 33.0 Debt funds (equity method accounting) 58,493 — Various Other fund investments (2) 302,659 8,901 Various Total $ 464,655 $ 16,142 (1) Our ownership includes direct ownership of 1.3 percent and indirect ownership of 3.8 percent through our investment in Strategic Investors Fund II, LP. (2) Represents commitments to 241 funds (primarily venture capital funds) where our ownership interest is generally less than five percent of the voting interests of each such fund. (3) We are subject to the Volcker Rule which restricts or limits us from sponsoring or having ownership interests in “covered” funds including venture capital and private equity funds. See “Business - Supervision and Regulation” under Part I, Item 1 of this report.
Remaining Unfunded Commitments to Venture Capital or Private Equity Funds by Consolidated Managed Funds	The following table details the amounts of remaining unfunded commitments to venture capital and private equity funds by our consolidated managed funds of funds (including our interest and the noncontrolling interests) at December 31, 2017 : (Dollars in thousands) Unfunded Commitments Strategic Investors Fund, LP $ 1,338 Capital Preferred Return Fund, LP 1,952 Growth Partners, LP 2,552 Total $ 5,842

Fair Value of Financial Instr52

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Hierarchy Tables Present Information about Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following fair value hierarchy table presents information about our assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2017 : (Dollars in thousands) Level 1 Level 2 Level 3 Balance at December 31, 2017 Assets Available-for-sale securities: U.S. Treasury securities $ 6,840,502 $ — $ — $ 6,840,502 U.S. agency debentures — 1,567,128 — 1,567,128 Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations - fixed rate — 2,267,035 — 2,267,035 Agency-issued collateralized mortgage obligations - variable rate — 373,730 — 373,730 Equity securities 158 72,111 — 72,269 Total available-for-sale securities 6,840,660 4,280,004 — 11,120,664 Non-marketable and other securities (fair value accounting): Non-marketable securities: Venture capital and private equity fund investments measured at net asset value — — — 127,192 Other venture capital investments (1) — — 919 919 Other securities (1) 310 — — 310 Total non-marketable and other securities (fair value accounting) 310 — 919 128,421 Other assets: Foreign exchange forward and option contracts — 96,636 — 96,636 Equity warrant assets — 2,432 121,331 123,763 Client interest rate derivatives — 11,753 — 11,753 Total assets $ 6,840,970 $ 4,390,825 $ 122,250 $ 11,481,237 Liabilities Foreign exchange forward and option contracts $ — $ 96,641 $ — $ 96,641 Client interest rate derivatives — 11,940 — 11,940 Total liabilities $ — $ 108,581 $ — $ 108,581 (1) Included in Level 1 and Level 3 assets are $0.2 million and $0.8 million , respectively, attributable to noncontrolling interests calculated based on the ownership percentages of the noncontrolling interests. The following fair value hierarchy table presents information about our assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2016 : (Dollars in thousands) Level 1 Level 2 Level 3 Balance at December 31, 2016 Assets Available-for-sale securities: U.S. Treasury securities $ 8,909,491 $ — $ — $ 8,909,491 U.S. agency debentures — 2,078,375 — 2,078,375 Residential mortgage-backed securities: Agency-issued collateralized mortgage obligations - fixed rate — 1,152,665 — 1,152,665 Agency-issued collateralized mortgage obligations - variable rate — 474,283 — 474,283 Equity securities 175 5,422 — 5,597 Total available-for-sale securities 8,909,666 3,710,745 — 12,620,411 Non-marketable and other securities (fair value accounting): Non-marketable securities: Venture capital and private equity fund investments measured at net asset value — — — 141,649 Other venture capital investments (1) — — 2,040 2,040 Other securities (1) 753 — — 753 Total non-marketable and other securities (fair value accounting) 753 — 2,040 144,442 Other assets: Interest rate swaps — 810 — 810 Foreign exchange forward and option contracts — 68,027 — 68,027 Equity warrant assets — 2,310 128,813 131,123 Client interest rate derivatives — 10,110 — 10,110 Total assets $ 8,910,419 $ 3,792,002 $ 130,853 $ 12,974,923 Liabilities Foreign exchange forward and option contracts $ — $ 54,668 $ — $ 54,668 Client interest rate derivatives — 9,770 — 9,770 Total liabilities $ — $ 64,438 $ — $ 64,438 (1) Included in Level 1 and Level 3 assets are $0.6 million and $1.8 million , respectively, attributable to noncontrolling interests calculated based on the ownership percentages of the noncontrolling interests.
Additional Information about Level 3 Assets Measured at Fair Value on a Recurring Basis	The following table presents additional information about Level 3 assets measured at fair value on a recurring basis for 2017 , 2016 and 2015 , respectively: (Dollars in thousands) Beginning Balance Total Realized and Unrealized Gains (Losses), net Included in Income Sales Issuances Distributions and Other Settlements Transfers Out of Level 3 Ending Balance Year ended December 31, 2017: Non-marketable and other securities (fair value accounting): Other venture capital investments (1) $ 2,040 $ 971 $ (2,092 ) $ — $ — $ — $ 919 Other assets: Equity warrant assets (2) 128,813 54,263 (74,769 ) 14,537 — (1,513 ) 121,331 Total assets $ 130,853 $ 55,234 $ (76,861 ) $ 14,537 $ — $ (1,513 ) $ 122,250 Year ended December 31, 2016: Non-marketable and other securities (fair value accounting): Other venture capital investments (1) $ 2,040 $ (21 ) $ (4 ) $ — $ 25 $ — $ 2,040 Other assets: Equity warrant assets (2) 135,168 38,091 (56,643 ) 13,405 — (1,208 ) 128,813 Total assets $ 137,208 $ 38,070 $ (56,647 ) $ 13,405 $ 25 $ (1,208 ) $ 130,853 Year ended December 31, 2015: Non-marketable and other securities (fair value accounting): Other venture capital investments $ 3,291 $ 1,192 $ (2,356 ) $ — $ (87 ) $ — $ 2,040 Other assets: Equity warrant assets (2) 114,698 71,402 (61,044 ) 12,534 — (2,422 ) 135,168 Total assets $ 117,989 $ 72,594 $ (63,400 ) $ 12,534 $ (87 ) $ (2,422 ) $ 137,208 (1) Realized and unrealized gains (losses) are recorded in the line item “Gains on investment securities, net”, a component of noninterest income. (2) Realized and unrealized gains (losses) are recorded in the line item “Gains on equity warrant assets, net”, a component of noninterest income.
Unrealized Gains Included in Earnings Attributable to Level 3 Assets Held	The following table presents the amount of unrealized gains (losses) included in earnings (which is inclusive of noncontrolling interest) attributable to Level 3 assets still held at December 31, 2017 and 2016 , respectively: Year ended December 31, (Dollars in thousands) 2017 2016 Non-marketable and other securities (fair value accounting): Other venture capital investments (1) $ (444 ) $ 1,739 Other assets: Equity warrant assets (2) 11,174 14,502 Total unrealized gains, net $ 10,730 $ 16,241 Unrealized (losses) gains attributable to noncontrolling interests $ (397 ) $ 1,553 (1) Unrealized gains are recorded on the line item “gains on investment securities, net”, a component of noninterest income. (2) Unrealized gains are recorded on the line item “gains on equity warrant assets, net”, a component of noninterest income.
Quantitative Information About Significant Unobservable Inputs	The following table presents quantitative information about the significant unobservable inputs used for certain of our Level 3 fair value measurements at December 31, 2017 and 2016 . We have not included in this table our venture capital and private equity fund investments (fair value accounting) as we use net asset value per share (as obtained from the general partners of the investments) as a practical expedient to determine fair value. (Dollars in thousands) Fair Value Valuation Technique Significant Unobservable Inputs Weighted Average December 31, 2017: Other venture capital investments (fair value accounting) $ 919 Private company equity pricing (1) (1) Equity warrant assets (public portfolio) 1,936 Black-Scholes option pricing model Volatility 47.9 % Risk-Free interest rate 2.1 Sales restrictions discount (2) 15.5 Equity warrant assets (private portfolio) 119,395 Black-Scholes option pricing model Volatility 36.7 Risk-Free interest rate 1.8 Marketability discount (3) 16.4 Remaining life assumption (4) 45.0 December 31, 2016: Other venture capital investments (fair value accounting) $ 2,040 Private company equity pricing (1) (1) Equity warrant assets (public portfolio) 764 Black-Scholes option pricing model Volatility 46.6 % Risk-Free interest rate 2.1 Sales restrictions discount (2) 17.7 Equity warrant assets (private portfolio) 128,049 Black-Scholes option pricing model Volatility 36.9 Risk-Free interest rate 1.3 Marketability discount (3) 17.1 Remaining life assumption (4) 45.0 (1) In determining the fair value of our other venture capital investment portfolio, we evaluate a variety of factors related to each underlying private portfolio company including, but not limited to, actual and forecasted results, cash position, recent or planned transactions and market comparable companies. Additionally, we have ongoing communication with the portfolio companies and venture capital fund managers, to determine whether there is a material change in fair value. We use company provided valuation reports, if available, to support our valuation assumptions. These factors are specific to each portfolio company and a weighted average or range of values of the unobservable inputs is not meaningful. (2) We adjust quoted market prices of public companies which are subject to certain sales restrictions. Sales restriction discounts generally range from 10 percent to 20 percent depending on the duration of the sales restrictions which typically range from three to six months. (3) Our marketability discount is applied to all private company warrants to account for a general lack of liquidity due to the private nature of the associated underlying company. The quantitative measure used is based on long-run averages and is influenced over time by various factors, including market conditions. On a quarterly basis, a sensitivity analysis is performed on our marketability discount. (4) We adjust the contractual remaining term of private company warrants based on our best estimate of the actual remaining life, which we determine by utilizing historical data on cancellations and exercises. At December 31, 2017 , the weighted average contractual remaining term was 6.0 years, compared to our estimated remaining life of 2.7 years. On a quarterly basis, a sensitivity analysis is performed on our remaining life assumption.
Summary of Estimated Fair Values of Financial Instruments Not Carried at Fair Value	The following fair value hierarchy table presents the estimated fair values of our financial instruments that are not carried at fair value at December 31, 2017 and 2016 : Estimated Fair Value (Dollars in thousands) Carrying Amount Total Level 1 Level 2 Level 3 December 31, 2017: Financial assets: Cash and cash equivalents $ 2,923,075 $ 2,923,075 $ 2,923,075 $ — $ — Held-to-maturity securities 12,663,455 12,548,280 — 12,548,280 — Non-marketable securities (cost and equity method accounting) not measured at net asset value 120,019 126,345 — — 126,345 Non-marketable securities (cost and equity method accounting) measured at net asset value (1) 228,399 331,496 — — — Net commercial loans 20,238,247 20,520,623 — — 20,520,623 Net consumer loans 2,613,045 2,593,538 — — 2,593,538 FHLB and FRB stock 60,020 60,020 — — 60,020 Accrued interest receivable 141,773 141,773 — 141,773 — Financial liabilities: Short-term FHLB advances 700,000 700,000 700,000 — — Federal funds purchased 330,000 330,000 330,000 — — Other short-term borrowings 3,730 3,730 3,730 — — Non-maturity deposits (2) 44,206,929 44,206,929 44,206,929 — — Time deposits 47,146 46,885 — 46,885 — 3.50% Senior Notes 347,303 352,058 — 352,058 — 5.375% Senior Notes 348,189 374,483 — 374,483 — Accrued interest payable 11,192 11,192 — 11,192 — Off-balance sheet financial assets: Commitments to extend credit — 22,208 — — 22,208 December 31, 2016: Financial assets: Cash and cash equivalents $ 2,545,750 $ 2,545,750 $ 2,545,750 $ — $ — Held-to-maturity securities 8,426,998 8,376,138 — 8,376,138 — Non-marketable securities (cost and equity method accounting) not measured at net asset value 120,037 127,343 — — 127,343 Non-marketable securities (cost and equity method accounting) measured at net asset value (1) 245,626 353,870 — — — Net commercial loans 17,518,430 17,811,356 — — 17,811,356 Net consumer loans 2,156,148 2,199,501 — — 2,199,501 FHLB and FRB stock 57,592 57,592 — — 57,592 Accrued interest receivable 111,222 111,222 — 111,222 — Financial liabilities: Short-term FHLB advances 500,000 500,000 500,000 — — Other short-term borrowings 12,668 12,668 12,668 — — Non-maturity deposits (2) 38,923,750 38,923,750 38,923,750 — — Time deposits 56,118 55,949 — 55,949 — 3.50% Senior Notes 346,979 337,600 — 337,600 — 5.375% Senior Notes 347,586 378,777 — 378,777 — 6.05% Subordinated Notes (3) 46,646 47,489 — 47,489 — 7.0% Junior Subordinated Debentures 54,493 53,140 — 53,140 — Accrued interest payable 12,013 12,013 — 12,013 — Off-balance sheet financial assets: Commitments to extend credit — 22,074 — — 22,074 (1) In accordance with the accounting standard (ASU 2015-07, Fair Value Measurement (Topic 820)), certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. (2) Includes noninterest-bearing demand deposits, interest-bearing checking accounts, money market accounts and interest-bearing sweep deposits. (3) At December 31, 2016 , included in the carrying value and estimated fair value of our 6.05% Subordinated Notes was $0.8 million related to hedge accounting associated with the notes.
Summary of Estimated Fair Values of Investments and Remaining Unfunded Commitments for Each Major Category of Investments	The following table is a summary of the estimated fair values of these investments and remaining unfunded commitments for each major category of these investments as of December 31, 2017 : (Dollars in thousands) Carrying Amount Fair Value Unfunded Commitments Non-marketable securities (fair value accounting): Venture capital and private equity fund investments (1) $ 127,192 $ 127,192 $ 5,842 Non-marketable securities (equity method accounting): Venture capital and private equity fund investments (2) 89,809 89,809 4,943 Debt funds (2) 21,183 21,183 — Other investments (2) 18,859 18,859 886 Non-marketable securities (cost method accounting): Venture capital and private equity fund investments (2) 98,548 201,645 8,015 Total $ 355,591 $ 458,688 $ 19,686 (1) Venture capital and private equity fund investments within non-marketable securities (fair value accounting) include investments made by our managed funds of funds and one of our direct venture funds. These investments represent investments in venture capital and private equity funds that invest primarily in U.S. and global technology and life science/healthcare companies. Included in the fair value and unfunded commitments of fund investments under fair value accounting are $94.2 million and $4.4 million , respectively, attributable to noncontrolling interests. It is estimated that we will receive distributions from the fund investments over the next 10 to 13 years, depending on the age of the funds and any potential extensions of terms of the funds. (2) Venture capital and private equity fund investments, debt funds, and other fund investments within non-marketable securities (equity and cost method accounting) include funds that invest in or lend money to primarily U.S. and global technology and life science/healthcare companies. It is estimated that we will receive distributions from the funds over the next 10 to 13 years, depending on the age of the funds and any potential extensions of the terms of the funds.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Capital Ratios for Company and Bank under Federal Regulatory Guidelines, Compared to Minimum Regulatory Capital Requirements for Adequately Capitalized and Well Capitalized Depository Institution	The following table presents the capital ratios for the Company and the Bank under federal regulatory guidelines, compared to the minimum regulatory capital requirements for an adequately capitalized and a well-capitalized depository institution, as of December 31, 2017 and 2016 : Capital Ratios Capital Amounts (Dollars in thousands) Actual Well Capitalized Minimum Adequately Capitalized Minimum Actual Well Capitalized Minimum Adequately Capitalized Minimum December 31, 2017: CET 1 risk-based capital: SVB Financial 12.78 % 6.5 % 4.5 % $ 4,182,315 $ 2,127,902 $ 1,473,163 Bank 12.06 6.5 4.5 3,787,988 2,041,227 1,413,157 Tier 1 risk-based capital: SVB Financial 12.97 8.0 6.0 4,246,606 2,618,957 1,964,218 Bank 12.06 8.0 6.0 3,787,988 2,512,279 1,884,209 Total risk-based capital: SVB Financial 13.96 10.0 8.0 4,571,542 3,273,696 2,618,957 Bank 13.04 10.0 8.0 4,094,782 3,140,349 2,512,279 Tier 1 leverage: SVB Financial 8.34 N/A 4.0 4,246,606 N/A 2,036,138 Bank 7.56 5.0 4.0 3,787,988 2,504,636 2,003,709 December 31, 2016: CET 1 risk-based capital: SVB Financial 12.80 % 6.5 % 4.5 % $ 3,616,404 $ 1,836,169 $ 1,271,194 Bank 12.65 6.5 4.5 3,397,232 1,745,695 1,208,558 Tier 1 risk-based capital: SVB Financial 13.26 8.0 6.0 3,744,605 2,259,900 1,694,925 Bank 12.65 8.0 6.0 3,397,232 2,148,548 1,611,411 Total risk-based capital: SVB Financial 14.21 10.0 8.0 4,015,236 2,824,875 2,259,900 Bank 13.66 10.0 8.0 3,667,709 2,685,685 2,148,548 Tier 1 leverage: SVB Financial 8.34 N/A 4.0 3,744,605 N/A 1,796,387 Bank 7.67 5.0 4.0 3,397,232 2,214,467 1,771,574

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Reporting	Our segment information for 2017 , 2016 and 2015 is as follows: (Dollars in thousands) Global Commercial Bank (1) SVB Private Bank SVB Capital (1) Other Items (2) Total Year ended December 31, 2017 Net interest income $ 1,274,366 $ 58,131 $ 48 $ 87,824 $ 1,420,369 Provision for credit losses (81,553 ) (4,386 ) — (6,365 ) (92,304 ) Noninterest income 366,000 2,175 58,992 130,064 557,231 Noninterest expense (3) (706,341 ) (17,693 ) (19,340 ) (267,281 ) (1,010,655 ) Income before income tax expense (4) $ 852,472 $ 38,227 $ 39,700 $ (55,758 ) $ 874,641 Total average loans, net of unearned income $ 18,479,793 $ 2,423,078 $ — $ 256,523 $ 21,159,394 Total average assets (5) 46,303,582 2,449,763 325,939 (699,012 ) 48,380,272 Total average deposits 41,043,731 1,303,542 — 397,875 42,745,148 Year ended December 31, 2016 Net interest income (expense) $ 1,040,712 $ 53,582 $ (49 ) $ 56,278 $ 1,150,523 Provision for credit losses (93,885 ) (1,812 ) — (10,982 ) (106,679 ) Noninterest income 320,421 2,713 49,365 84,053 456,552 Noninterest expense (3) (632,264 ) (12,379 ) (15,546 ) (199,608 ) (859,797 ) Income before income tax expense (4) $ 634,984 $ 42,104 $ 33,770 $ (70,259 ) $ 640,599 Total average loans, net of unearned income $ 16,047,545 $ 2,025,381 $ — $ 210,665 $ 18,283,591 Total average assets (5) 41,494,321 2,047,513 338,848 106,769 43,987,451 Total average deposits 37,301,483 1,133,425 — 324,151 38,759,059 Year ended December 31, 2015 Net interest income $ 853,882 $ 44,412 $ 3 $ 108,128 $ 1,006,425 (Provision for) reduction of credit losses (94,913 ) (2,716 ) — 1,946 (95,683 ) Noninterest income 272,862 2,011 70,857 127,064 472,794 Noninterest expense (3) (578,888 ) (12,185 ) (14,699 ) (174,190 ) (779,962 ) Income before income tax expense (4) $ 452,943 $ 31,522 $ 56,161 $ 62,948 $ 603,574 Total average loans, net of unearned income $ 12,984,646 $ 1,592,065 $ — $ 186,230 $ 14,762,941 Total average assets (5) 38,438,858 1,457,461 337,884 612,174 40,846,377 Total average deposits 34,996,194 1,108,411 — 188,757 36,293,362 (1) Global Commercial Bank’s and SVB Capital’s components of net interest income, noninterest income, noninterest expense and total average assets are shown net of noncontrolling interests for all periods presented. Noncontrolling interest is included within "Other Items". (2) The "Other Items" column reflects the adjustments necessary to reconcile the results of the operating segments to the consolidated financial statements prepared in conformity with GAAP. Net interest income consists primarily of interest earned from our fixed income investment portfolio, net of FTP. Noninterest income consists primarily of gains on equity warrant assets, income from noncontrolling interests and gains or losses on the sale of fixed income securities. Noninterest expense consists primarily of expenses associated with corporate support functions such as finance, human resources, marketing, legal and other expenses. (3) The Global Commercial Bank segment includes direct depreciation and amortization of $24.9 million , $24.8 million and $20.3 million for 2017 , 2016 and 2015 , respectively. (4) The internal reporting model used by management to assess segment performance does not calculate income tax expense by segment. Our effective tax rate is a reasonable approximation of the segment rates. (5) Total average assets equal the greater of total average assets or the sum of total average liabilities and total average stockholders’ equity for each segment to reconcile the results to the consolidated financial statements prepared in conformity with GAAP.

Parent Company Only Condensed55

Parent Company Only Condensed Financial Information (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Balance Sheets	The condensed balance sheets of SVB Financial at December 31, 2017 and 2016 , and the related condensed statements of income, comprehensive income and cash flows for 2017 , 2016 and 2015 , are presented below: Condensed Balance Sheets December 31, (Dollars in thousands) 2017 2016 Assets: Cash and cash equivalents $ 457,324 $ 500,014 Investment securities 485,220 244,603 Net loans — 13,337 Other assets 196,974 197,220 Investment in subsidiaries: Bank subsidiary 3,762,542 3,423,427 Nonbank subsidiaries 90,540 113,928 Total assets $ 4,992,600 $ 4,492,529 Liabilities and SVBFG stockholders’ equity: 3.50% Senior Notes $ 347,303 $ 346,979 5.375% Senior Notes 348,189 347,586 7.0% Junior Subordinated Debentures — 54,493 Other liabilities 117,313 100,917 Total liabilities $ 812,805 $ 849,975 SVBFG stockholders’ equity 4,179,795 3,642,554 Total liabilities and SVBFG stockholders’ equity $ 4,992,600 $ 4,492,529
Condensed Statements of Income	Condensed Statements of Income Year ended December 31, (Dollars in thousands) 2017 2016 2015 Interest income $ 2,077 $ 690 $ 964 Interest expense (34,932 ) (35,316 ) (34,169 ) Dividend income from bank subsidiary 90,000 40,000 — Gains on equity warrant assets, net (1) 54,555 37,892 70,963 Gains on investment securities, net 37,132 20,644 39,447 Fund management fees and other noninterest income (1) 24,613 21,913 2,286 General and administrative expenses (63,077 ) (55,139 ) (54,822 ) Income tax benefit (expense) 10,367 423 (14,448 ) Income before net income of subsidiaries 120,735 31,107 10,221 Equity in undistributed net income of nonbank subsidiaries 13,002 11,949 26,819 Equity in undistributed net income of bank subsidiary 356,769 339,629 306,864 Net income available to common stockholders $ 490,506 $ 382,685 $ 343,904 (1) Our consolidated statements of income for the years ended December 31, 2016 and 2015 were modified from prior periods’ presentation to conform to the current period's presentation, which reflects a new line item to separately disclose net gains on equity warrant assets. In prior periods, net gains on equity warrant assets were reported as a component of net gains on derivative instruments. We removed the line item "gains on derivative instruments, net" and reclassified all other gains on derivative instruments, net to other noninterest income.
Condensed Statements of Comprehensive Income	Condensed Statements of Comprehensive Income Year ended December 31, (Dollars in thousands) 2017 2016 2015 Net income available to common stockholders $ 490,506 $ 382,685 $ 343,904 Other comprehensive (loss) income, net of tax: Foreign currency translation gains (losses) 3,769 3,071 (1,492 ) Changes in unrealized holding gains and losses on AFS securities 22,285 654 (2,041 ) Equity in other comprehensive (losses) income of subsidiaries (50,956 ) 4,301 (23,767 ) Other comprehensive (loss) income, net of tax (24,902 ) 8,026 (27,300 ) Total comprehensive income $ 465,604 $ 390,711 $ 316,604
Condensed Statements of Cash Flows	Condensed Statements of Cash Flows Year ended December 31, (Dollars in thousands) 2017 2016 2015 Cash flows from operating activities: Net income attributable to SVBFG $ 490,506 $ 382,685 $ 343,904 Adjustments to reconcile net income to net cash used for operating activities: Gains on equity warrant assets, net (54,555 ) (37,892 ) (70,963 ) Gains on investment securities, net (37,132 ) (20,644 ) (39,447 ) Net income of bank subsidiary (446,769 ) (379,629 ) (306,864 ) Net income on nonbank subsidiaries (13,002 ) (11,949 ) (26,819 ) Cash dividends from bank subsidiary 90,000 40,000 — Amortization of share-based compensation 36,900 35,494 32,239 Decrease (increase) in other assets 12,959 35,699 (30,638 ) Increase in other liabilities 11,774 15,293 28,985 Other, net 131 2,992 15,956 Net cash provided by (used for) operating activities 90,812 62,049 (53,647 ) Cash flows from investing activities: Net (increase) decrease in investment securities from purchases, sales and maturities (117,743 ) 54,737 31,380 Net decrease (increase) in loans 13,337 (3,478 ) 6,825 Increase in investment in bank subsidiary (38,927 ) (14,738 ) (378,286 ) Decrease in investment in nonbank subsidiaries 34,374 1,924 71,062 Net cash (used for) provided by investing activities (108,959 ) 38,445 (269,019 ) Cash flows from financing activities: Principal payments of long-term debt (51,546 ) — — Proceeds from issuance of common stock, ESPP and ESOP 27,003 26,147 22,410 Tax effect from stock exercises (1) — (3,640 ) 16,602 Net proceeds from issuance of long-term debt — — 346,431 Net cash (used for) provided by financing activities (24,543 ) 22,507 385,443 Net (decrease) increase in cash and cash equivalents (42,690 ) 123,001 62,777 Cash and cash equivalents at beginning of period 500,014 377,013 314,236 Cash and cash equivalents at end of period $ 457,324 $ 500,014 $ 377,013

Unaudited Quarterly Financial56

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Supplemental Consolidated Financial Information	Our supplemental consolidated financial information for each three month period in 2017 and 2016 are as follows: Three months ended (Dollars in thousands, except per share amounts) March 31, June 30, September 30, December 31, 2017: Interest income $ 320,926 $ 353,927 $ 385,271 $ 405,016 Interest expense 10,933 11,231 11,297 11,310 Net interest income 309,993 342,696 373,974 393,706 Provision for credit losses 30,734 15,806 23,522 22,242 Noninterest income 117,659 128,528 158,778 152,266 Noninterest expense 237,633 251,246 257,761 264,015 Income before income tax expense 159,285 204,172 251,469 259,715 Income tax expense (1) 51,405 71,656 97,351 135,051 Net income before noncontrolling interests 107,880 132,516 154,118 124,664 Net income attributable to noncontrolling interests (6,397 ) (9,323 ) (5,498 ) (7,454 ) Net income available to common stockholders (1) $ 101,483 $ 123,193 $ 148,620 $ 117,210 Earnings per common share—basic (1) $ 1.94 $ 2.34 $ 2.82 $ 2.22 Earnings per common share—diluted (1) 1.91 2.32 2.79 2.19 2016: Interest income $ 291,658 $ 293,992 $ 300,413 $ 307,333 Interest expense 10,237 10,656 11,252 10,728 Net interest income 281,421 283,336 289,161 296,605 Provision for credit losses (2) 33,475 36,746 20,004 16,454 Noninterest income 86,134 112,776 144,140 113,502 Noninterest expense (2) 203,899 199,939 220,773 235,186 Income before income tax expense 130,181 159,427 192,524 158,467 Income tax expense 53,584 65,047 76,877 54,825 Net income before noncontrolling interests 76,597 94,380 115,647 103,642 Net loss (income) attributable to noncontrolling interests 2,577 (1,416 ) (4,566 ) (4,176 ) Net income available to common stockholders $ 79,174 $ 92,964 $ 111,081 $ 99,466 Earnings per common share—basic $ 1.53 $ 1.79 $ 2.13 $ 1.91 Earnings per common share—diluted 1.52 1.78 2.12 1.89

Nature of Business (Details)

Nature of Business (Details)	12 Months Ended
	Dec. 31, 2017Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	3

Summary of Significant Accoun58

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Significant Accounting Policies [Line Items]
Operating Leases, Future Minimum Payments Due		$ 226,475
Lower Limit
Significant Accounting Policies [Line Items]
Derivative, Term of Contract		1 year
Marketability discount		10.00%
Duration of the sale restrictions		3 months
Upper Limit
Significant Accounting Policies [Line Items]
Derivative, Term of Contract		5 years
Marketability discount		20.00%
Duration of the sale restrictions		6 months
Percentage of voting interest held by the company for investments accounted for under the equity method		5.00%	5.00%
Investments in limited partnerships | Lower Limit
Significant Accounting Policies [Line Items]
Percentage of voting interest held by the company for investments accounted for under the equity method		5.00%
Investments in limited partnerships | Upper Limit
Significant Accounting Policies [Line Items]
Percentage of ownership interest held by the company for investments accounted for under the cost method		5.00%
Privately Held Companies | Lower Limit
Significant Accounting Policies [Line Items]
Percentage of voting interest held by the company for investments accounted for under the equity method		20.00%
Accounting Standards Update 2016-09 [Member]
Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income		$ 18,000
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Diluted Earnings Per Share		$ 0.34
Scenario, Forecast [Member] | Accounting Standards Update 2016-09
Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 8,000
Scenario, Forecast [Member] | Accounting Standards Update 2016-02 [Member]
Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	226,000
Scenario, Forecast [Member] | Accounting Standards Update 2018-02 [Domain]
Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	0
Other investments | China Joint Venture investment | Equity method accounting
Significant Accounting Policies [Line Items]
Ownership percentage of each Fund		50.00%	50.00%
Venture capital and private equity fund investments | Scenario, Forecast [Member] | Accounting Standards Update 2016-01 [Member] | Cost method accounting
Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	100,000
Equity securities | Scenario, Forecast [Member] | Accounting Standards Update 2016-01 [Member]
Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 40,000

Summary of Significant Accoun59

Summary of Significant Accounting Policies Maximum Estimated Useful Lives by Asset Classification (Detail)	12 Months Ended
	Dec. 31, 2017
Leasehold Improvements
Property Plant and Equipment Estimated Useful Lives [Line Items]
Premises and equipment, description of estimated useful life	Lesser of lease term or asset life
Furniture and equipment
Property Plant and Equipment Estimated Useful Lives [Line Items]
Premises and equipment, description of estimated useful life	7 years
Premises and equipment, estimated useful life	7 years
Software
Property Plant and Equipment Estimated Useful Lives [Line Items]
Premises and equipment, description of estimated useful life	3-7 years
Software | Lower Limit
Property Plant and Equipment Estimated Useful Lives [Line Items]
Premises and equipment, estimated useful life	3 years
Software | Upper Limit
Property Plant and Equipment Estimated Useful Lives [Line Items]
Premises and equipment, estimated useful life	7 years
Computer hardware
Property Plant and Equipment Estimated Useful Lives [Line Items]
Premises and equipment, description of estimated useful life	3-5 years
Computer hardware | Lower Limit
Property Plant and Equipment Estimated Useful Lives [Line Items]
Premises and equipment, estimated useful life	3 years
Computer hardware | Upper Limit
Property Plant and Equipment Estimated Useful Lives [Line Items]
Premises and equipment, estimated useful life	5 years

Stockholders' Equity and EPS Re

Stockholders' Equity and EPS Reclassification of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Related tax (benefit) expense	$ (135,051)	$ (97,351)	$ (71,656)	$ (51,405)	$ (54,825)	$ (76,877)	$ (65,047)	$ (53,584)	$ (355,463)	[1]	$ (250,333)	$ (228,754)
Net income available to common stockholders	$ 117,210	$ 148,620	$ 123,193	$ 101,483	$ 99,466	$ 111,081	$ 92,964	$ 79,174	490,506	[1]	382,685	343,904
Accumulated Net Unrealized Investment Gain (Loss) | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassification adjustment for losses (gains) included in net income									5,189		(12,195)	(1,201)
Related tax (benefit) expense									(2,098)		4,963	481
Net income available to common stockholders									$ 3,091		$ (7,232)	$ (720)
[1]	Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted, for the year ended December 31, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update ("ASU") 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.

Stockholders' Equity and EPS 61

Stockholders' Equity and EPS Reconciliation of Basic EPS to Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Numerator:
Net income available to common stockholders	$ 117,210	$ 148,620	$ 123,193	$ 101,483	$ 99,466	$ 111,081	$ 92,964	$ 79,174	$ 490,506	[1]	$ 382,685	$ 343,904
Denominator:
Weighted average common shares outstanding-basic (in shares)									52,588		51,915	51,318
Denominator for diluted calculation (in shares)									53,306		52,349	51,916
Earnings per common share:
Basic (usd per share)	$ 2.22	$ 2.82	$ 2.34	$ 1.94	$ 1.91	$ 2.13	$ 1.79	$ 1.53	$ 9.33	[1]	$ 7.37	$ 6.70
Diluted (usd per share)	$ 2.19	$ 2.79	$ 2.32	$ 1.91	$ 1.89	$ 2.12	$ 1.78	$ 1.52	$ 9.20	[1]	$ 7.31	$ 6.62
Stock options and ESPP
Denominator:
Weighted average effect of dilutive securities (in shares)									385		254	387
Restricted stock units
Denominator:
Weighted average effect of dilutive securities (in shares)									333		180	211
[1]	Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted, for the year ended December 31, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update ("ASU") 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.

Stockholders' Equity and EPS Co

Stockholders' Equity and EPS Common Shares Excluded from Diluted EPS Calculation as They Were Deemed to be Anti-Dilutive (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	74	273	185
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	73	272	185
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	1	1	0

Share Based Compensation and Re

Share Based Compensation and Related Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based compensation expense	$ 36,900	$ 35,494	$ 32,239
Income tax benefit related to share-based compensation expense	(12,845)	(12,505)	(11,395)
Capitalized compensation costs	$ 1,071	$ 5,580	$ 2,226

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Expected volatility term	5 years
Closing stock price | $ / shares	$ 233.77
Equity Incentive Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,091,064
Maximum aggregate number of shares that may be awarded and sold	9,528,505
Conversion ratio for awards granted	2
Conversion ratio for awards forfeited	2
Equity Incentive Plan | Restricted stock units
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Options, exercisable period	4 years
Equity Incentive Plan | Restricted stock units | Lower Limit
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Options, exercisable period	3 years
Equity Incentive Plan | Performance-based restricted stock
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Options, exercisable period	3 years
Equity Incentive Plan | Performance-based restricted stock | Lower Limit
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Options, exercisable period	1 year
Equity Incentive Plan | Stock options
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Options granted under the 2006 Incentive Plan, expiration period	7 years
Options, exercisable period	4 years
Employee Stock Purchase Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,614,399
Maximum percentage of gross compensation that participating employees may annually contribute towards ESPP	10.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount | $	$ 25,000
Percentage of fair market value of common stock at which employees may purchase shares under ESPP	85.00%
Number of shares issued under ESPP	122,882
Proceeds from issuance of shares under ESPP | $	$ 18,200,000

Share-Based Compensation Unreco

Share-Based Compensation Unrecognized Share-Based Compensation Expense (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 60,160
Stock option
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 9,630
Average Expected Recognition Period - in Years	2 years 7 months 3 days
Restricted stock units
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 50,530
Average Expected Recognition Period - in Years	2 years 7 months 3 days

Share-Based Compensation Weight

Share-Based Compensation Weighted Average Assumptions and Fair Values Used for Employee Stock Options and Restricted Stock Units (Detail) - Equity Incentive Plan - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Weighted average expected term of options in years	4 years 10 months 15 days	4 years 10 months 2 days	4 years 8 months 27 days
Weighted average expected volatility of the Company's underlying common stock	33.70%	31.70%	31.30%
Risk-free interest rate	1.81%	1.32%	1.49%
Expected dividend yield	$ 0	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 57.81	$ 31.17	$ 37.86
Weighted average grant date fair value-restricted stock units (usd per share)	$ 181.23	$ 100.35	$ 129.23

Share-Based Compensation Weig67

Share-Based Compensation Weighted Average Assumptions and Fair Values Used for ESPP (Detail) - Employee Stock Purchase Plan - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Expected term in years	6 months	6 months	6 months
Weighted average expected volatility of the Company's underlying common stock	31.20%	41.80%	25.90%
Risk-free interest rate	0.80%	0.45%	0.12%
Expected dividend yield	$ 0	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 41.70	$ 29.16	$ 29.27

Share-Based Compensation Stock

Share-Based Compensation Stock Option Information Related to Equity Incentive Plan (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Options
Outstanding, beginning of period (in shares) | shares	1,010,557
Granted (in shares) | shares	116,995
Exercised (in shares) | shares	(302,744)
Forfeited (in shares) | shares	(16,759)
Outstanding, end of period (in shares) | shares	808,049
Vested and expected to vest (in shares) | shares	787,182
Exercisable (in shares) | shares	464,685
Weighted average exercise price
Outstanding, beginning of period (usd per share) | $ / shares	$ 87.24
Granted (usd per share) | $ / shares	179.39
Exercised (usd per share) | $ / shares	71.65
Forfeited (usd per share) | $ / shares	122.97
Outstanding, end of period (usd per share) | $ / shares	105.68
Vested and expected to vest (usd per share) | $ / shares	104.69
Exercisable (usd per share) | $ / shares	$ 84.86
Weighted Average Remaining Contractual Life in Years
Outstanding (in years)	3 years 8 months 9 days
Vested and expected to vest (in years)	3 years 7 months 19 days
Exercisable (in years)	2 years 6 months 25 days
Aggregate Intrinsic Value of In-The-Money Options
Outstanding | $	$ 103,506,420
Vested and expected to vest | $	101,607,636
Exercisable | $	$ 69,197,233

Share-Based Compensation Stoc69

Share-Based Compensation Stock Options Outstanding (Detail)	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding Options, Shares | shares	808,049
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	3 years 8 months 8 days
Outstanding Options, Weighted Average Exercise Price	$ 105.68
Exercisable Options, Shares | shares	464,685
Exercisable Options, Weighted Average Exercise Price	$ 84.86
$42.79 - 63.62
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	42.79
Range of Exercise Prices, maximum	$ 63.62
Outstanding Options, Shares | shares	52,630
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	6 months 7 days
Outstanding Options, Weighted Average Exercise Price	$ 59.22
Exercisable Options, Shares | shares	52,630
Exercisable Options, Weighted Average Exercise Price	$ 59.22
63.63 - 67.77
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	63.63
Range of Exercise Prices, maximum	$ 67.77
Outstanding Options, Shares | shares	84,961
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	1 year 3 months 29 days
Outstanding Options, Weighted Average Exercise Price	$ 64.37
Exercisable Options, Shares | shares	84,961
Exercisable Options, Weighted Average Exercise Price	$ 64.37
67.78 - 79.77
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	67.78
Range of Exercise Prices, maximum	$ 79.77
Outstanding Options, Shares | shares	141,026
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	2 years 3 months 29 days
Outstanding Options, Weighted Average Exercise Price	$ 71.11
Exercisable Options, Shares | shares	141,026
Exercisable Options, Weighted Average Exercise Price	$ 71.11
79.78 - 105.14
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	79.78
Range of Exercise Prices, maximum	$ 105.14
Outstanding Options, Shares | shares	11,686
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	3 years 8 months 1 day
Outstanding Options, Weighted Average Exercise Price	$ 98.17
Exercisable Options, Shares | shares	7,336
Exercisable Options, Weighted Average Exercise Price	$ 96.09
105.15 - 105.84
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	105.15
Range of Exercise Prices, maximum	$ 105.84
Outstanding Options, Shares | shares	154,345
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	5 years 3 months 29 days
Outstanding Options, Weighted Average Exercise Price	$ 105.18
Exercisable Options, Shares | shares	31,958
Exercisable Options, Weighted Average Exercise Price	$ 105.18
105.85 - 108.59
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	105.85
Range of Exercise Prices, maximum	$ 108.59
Outstanding Options, Shares | shares	148,456
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	3 years 3 months 27 days
Outstanding Options, Weighted Average Exercise Price	$ 107.96
Exercisable Options, Shares | shares	101,824
Exercisable Options, Weighted Average Exercise Price	$ 107.95
108.60 - 149.65
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	108.60
Range of Exercise Prices, maximum	$ 149.65
Outstanding Options, Shares | shares	102,306
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	4 years 3 months 8 days
Outstanding Options, Weighted Average Exercise Price	$ 128.65
Exercisable Options, Shares | shares	44,950
Exercisable Options, Weighted Average Exercise Price	$ 128.13
149.66 - 180.62
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	149.66
Range of Exercise Prices, maximum	$ 180.62
Outstanding Options, Shares | shares	108,266
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	6 years 4 months 3 days
Outstanding Options, Weighted Average Exercise Price	$ 178.15
Exercisable Options, Shares | shares	0
Exercisable Options, Weighted Average Exercise Price	$ 0
180.63 - 217.69
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	180.63
Range of Exercise Prices, maximum	$ 217.69
Outstanding Options, Shares | shares	4,373
Outstanding Options ,Weighted Average Remaining Contractual Life in Years	6 years 9 months 17 days
Outstanding Options, Weighted Average Exercise Price	$ 210.42
Exercisable Options, Shares | shares	0
Exercisable Options, Weighted Average Exercise Price	$ 0

Share-Based Compensation Inform

Share-Based Compensation Information for Restricted Stock Units under Equity Incentive Plan (Detail) - Restricted stock units	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Shares
Nonvested, beginning of period (in shares) | shares	670,969
Granted (in shares) | shares	247,591
Vested (in shares) | shares	(228,198)
Forfeited (in shares) | shares	(52,695)
Nonvested, end of period (in shares) | shares	637,667
Weighted Average Grant Date Fair Value
Nonvested, beginning of period (usd per share) | $ / shares	$ 106.64
Granted (usd per share) | $ / shares	181.23
Vested (usd per share) | $ / shares	102.47
Forfeited (usd per share) | $ / shares	121.52
Nonvested, end of period (usd per share) | $ / shares	$ 135.86

Share-Based Compensation Summar

Share-Based Compensation Summary of Information Regarding Stock Option and Restricted Stock Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of stock options exercised	$ 36,173	$ 18,186	$ 27,430
Total grant date fair value of stock options vested	6,094	7,364	21,052
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of restricted stock vested	40,925	22,966	34,009
Total grant date fair value of restricted stock vested	$ 23,383	$ 19,454	$ 19,428

Variable Interest Entities - Ca

Variable Interest Entities - Carrying Amounts and Classification of Significant Variable Interests (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	[1]
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 2,923,075	$ 2,545,750	$ 1,503,257	$ 1,811,014
Non-marketable and other securities	651,053	622,552
Accrued interest receivable and other assets	876,246	672,688
Total assets	51,214,467	44,683,660
Other liabilities	911,755	618,383
Total liabilities	46,895,052	40,906,623
Maximum Exposure to Loss in Unconsolidated VIEs	346,097	314,810
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	6,674	11,469
Non-marketable and other securities	190,562	196,140
Accrued interest receivable and other assets	365	294
Total assets	197,601	207,903
Accrued expenses and other liabilities	990	517
Total liabilities	990	517
Maximum Exposure to Loss in Unconsolidated VIEs	196,600
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	0	0
Non-marketable and other securities	346,097	314,810
Accrued interest receivable and other assets	0	0
Total assets	346,097	314,810
Accrued expenses and other liabilities	100,891	58,095
Total liabilities	$ 100,891	$ 58,095
[1]	Cash and cash equivalents at December 31, 2014 included $15.0 million recognized in assets held-for-sale in conjunction with the SVBIF sale transaction. On April 13, 2015 we received net proceeds of $39.3 million consisting of the sales price of $48.6 million less $9.3 million of cash and cash equivalents held by SVBIF that were sold.

Variable Interest Entities - Ad

Variable Interest Entities - Additional Information (Details) $ in Thousands	Dec. 31, 2017USD ($)entity	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Variable Interest Entity [Line Items]
Amortization method qualified affordable housing project investments	$ 174,214	$ 112,447
Qualified Affordable Housing Project Investments, Commitment	100,891	58,095
Total assets	(51,214,467)	(44,683,660)
Total equity	$ (4,319,415)	(3,777,037)	$ (3,333,231)	$ (4,051,734)
Number of consolidated entities | entity	4
Maximum Exposure to Loss in Unconsolidated VIEs	$ 346,097	314,810
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Total assets	(346,097)	(314,810)
Accrued expenses and other liabilities	100,891	58,095
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Total assets	(197,601)	(207,903)
Accrued expenses and other liabilities	990	$ 517
Maximum Exposure to Loss in Unconsolidated VIEs	$ 196,600

Reserves on Deposit with the 74

Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock Average Required Reserve Balances (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock [Abstract]
Average required reserve balances at FRB San Francisco	$ 397,235	$ 370,002

Reserves on Deposit with the 75

Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock Shares Held at Federal Reserve Bank and Federal Home Loan Bank (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Disclosure Shares Held At Federal Reserve Bank And Federal Home Loan Bank [Abstract]
FHLB stock holdings	$ 18,900	$ 17,250
FRB stock holdings	$ 41,120	$ 40,342

Cash and Cash Equivalents (Deta

Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	[1]
Cash and Cash Equivalents [Abstract]
Cash and due from banks	$ 2,672,290	$ 2,476,588
Securities purchased under agreements to resell	247,876	64,028
Other short-term investment securities	2,909	5,134
Total cash and cash equivalents	$ 2,923,075	$ 2,545,750	$ 1,503,257	$ 1,811,014
[1]	Cash and cash equivalents at December 31, 2014 included $15.0 million recognized in assets held-for-sale in conjunction with the SVBIF sale transaction. On April 13, 2015 we received net proceeds of $39.3 million consisting of the sales price of $48.6 million less $9.3 million of cash and cash equivalents held by SVBIF that were sold.

Cash and Cash Equivalents (Foot

Cash and Cash Equivalents (Footnote Information) (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Fair Value of Securities Received as Collateral that Have Been Resold or Repledged	$ 0	$ 0
Deposits at the Federal Reserve Bank earning interest at the Federal Funds target rate	600,000,000	1,100,000,000
Interest-earning deposits in other financial institutions	1,100,000,000	721,000,000
Fair value of securities purchased under agreements to resell	$ 253,000,000	$ 66,000,000

Cash and Cash Equivalents Secur

Cash and Cash Equivalents Securities Purchased Under Agreements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Disclosure Securities Purchased Under Agreements [Abstract]
Average securities purchased under agreements to resell	$ 94,094	$ 90,362
Maximum amount outstanding at any month-end during the year	$ 377,073	$ 316,059

Investment Securities - Major C

Investment Securities - Major Components of Investment Securities Portfolio (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Investment Holdings [Line Items]
Amortized Cost	$ 11,131,008	$ 12,588,783
Unrealized Gains	46,840	49,245
Unrealized Losses	(57,184)	(17,617)
Carrying Value	11,120,664	12,620,411
U.S. treasury securities
Investment Holdings [Line Items]
Amortized Cost	6,865,068	8,880,358
Unrealized Gains	1,113	30,323
Unrealized Losses	(25,679)	(1,190)
Carrying Value	6,840,502	8,909,491
U.S. agency debentures
Investment Holdings [Line Items]
Amortized Cost	1,569,195	2,065,535
Unrealized Gains	3,569	14,443
Unrealized Losses	(5,636)	(1,603)
Carrying Value	1,567,128	2,078,375
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Investment Holdings [Line Items]
Amortized Cost	2,292,311	1,163,017
Unrealized Gains	258	3,046
Unrealized Losses	(25,534)	(13,398)
Carrying Value	2,267,035	1,152,665
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Investment Holdings [Line Items]
Amortized Cost	372,481	474,238
Unrealized Gains	1,375	685
Unrealized Losses	(126)	(640)
Carrying Value	373,730	474,283
Equity securities
Investment Holdings [Line Items]
Amortized Cost	31,953	5,635
Unrealized Gains	40,525	748
Unrealized Losses	(209)	(786)
Carrying Value	$ 72,269	$ 5,597

Investment Securities - Summary

Investment Securities - Summary of Available for Sale Securities (Detail) $ in Thousands	Dec. 31, 2017USD ($)Investment	Dec. 31, 2016USD ($)Investment
Investments, Unrealized Loss Position [Line Items]
Less than 12 months - Fair Value of Investments	$ 8,913,199	$ 2,290,037
Less than 12 months - Unrealized Losses	(51,432)	(10,896)
12 months or longer - Fair Value of Investments	713,348	233,548
12 months or longer - Unrealized Losses	(5,752)	(6,721)
Fair Value of Investments	9,626,547	2,523,585
Unrealized Losses	$ (57,184)	$ (17,617)
Number of investments in unrealized loss position | Investment	268	174
Number of investments with unrealized losses greater than 12 months | Investment	46	20
U.S. treasury securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months - Fair Value of Investments	$ 5,968,914	$ 879,255
Less than 12 months - Unrealized Losses	(23,397)	(1,190)
12 months or longer - Fair Value of Investments	323,966	0
12 months or longer - Unrealized Losses	(2,282)	0
Fair Value of Investments	6,292,880	879,255
Unrealized Losses	(25,679)	(1,190)
U.S. agency debentures
Investments, Unrealized Loss Position [Line Items]
Less than 12 months - Fair Value of Investments	736,541	513,198
Less than 12 months - Unrealized Losses	(2,289)	(1,603)
12 months or longer - Fair Value of Investments	336,196	0
12 months or longer - Unrealized Losses	(3,347)	0
Fair Value of Investments	1,072,737	513,198
Unrealized Losses	(5,636)	(1,603)
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Investments, Unrealized Loss Position [Line Items]
Less than 12 months - Fair Value of Investments	2,193,277	635,566
Less than 12 months - Unrealized Losses	(25,534)	(6,704)
12 months or longer - Fair Value of Investments	0	227,480
12 months or longer - Unrealized Losses	0	(6,694)
Fair Value of Investments	2,193,277	863,046
Unrealized Losses	(25,534)	(13,398)
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Investments, Unrealized Loss Position [Line Items]
Less than 12 months - Fair Value of Investments	13,843	258,325
Less than 12 months - Unrealized Losses	(3)	(613)
12 months or longer - Fair Value of Investments	53,186	6,068
12 months or longer - Unrealized Losses	(123)	(27)
Fair Value of Investments	67,029	264,393
Unrealized Losses	(126)	(640)
Equity securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months - Fair Value of Investments	624	3,693
Less than 12 months - Unrealized Losses	(209)	(786)
12 months or longer - Fair Value of Investments	0	0
12 months or longer - Unrealized Losses	0	0
Fair Value of Investments	624	3,693
Unrealized Losses	$ (209)	$ (786)

Investment Securities - Summa81

Investment Securities - Summary of Remaining Contractual Principal Maturities and Fully Taxable Equivalent Yields on Debt Securities Classified as Available for Sale (Detail) - Available-for-sale Securities $ in Thousands	Dec. 31, 2017USD ($)
Investments Classified By Contractual Maturity Date [Line Items]
Carrying Value	$ 11,048,395
One Year or Less - Carrying Value	2,448,760
After One Year to Five Years - Carrying Value	5,958,870
After Five Years to Ten Years - Carrying Value	88,425
After Ten Years - Carrying Value	2,552,340
U.S. treasury securities
Investments Classified By Contractual Maturity Date [Line Items]
Carrying Value	6,840,502
One Year or Less - Carrying Value	1,967,480
After One Year to Five Years - Carrying Value	4,873,022
After Five Years to Ten Years - Carrying Value	0
After Ten Years - Carrying Value	0
U.S. agency debentures
Investments Classified By Contractual Maturity Date [Line Items]
Carrying Value	1,567,128
One Year or Less - Carrying Value	481,280
After One Year to Five Years - Carrying Value	1,085,848
After Five Years to Ten Years - Carrying Value	0
After Ten Years - Carrying Value	0
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Investments Classified By Contractual Maturity Date [Line Items]
Carrying Value	2,267,035
One Year or Less - Carrying Value	0
After One Year to Five Years - Carrying Value	0
After Five Years to Ten Years - Carrying Value	88,425
After Ten Years - Carrying Value	2,178,610
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Investments Classified By Contractual Maturity Date [Line Items]
Carrying Value	373,730
One Year or Less - Carrying Value	0
After One Year to Five Years - Carrying Value	0
After Five Years to Ten Years - Carrying Value	0
After Ten Years - Carrying Value	$ 373,730

Investment Securities - Summa82

Investment Securities - Summary Held to Maturity Securities (Details) $ in Thousands	Dec. 31, 2017USD ($)Investment	Dec. 31, 2016USD ($)Investment
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 12,663,455	$ 8,426,998
Unrealized Gains	12,923	16,968
Unrealized Losses	(128,098)	(67,828)
Fair Value	12,548,280	8,376,138
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value of Investments, Less than 12 months	6,710,931	5,943,190
Unrealized Losses, Less than 12 months	(62,993)	(60,189)
Fair Value of Investments, 12 months or longer	2,966,895	295,657
Unrealized Losses, 12 months or longer	(65,105)	(7,639)
Fair Value of Investments	9,677,826	6,238,847
Unrealized Losses	$ (128,098)	$ (67,828)
Number of held-to-maturity investments with unrealized loss | Investment	753	462
Number of held-to-maturity investments in continuous loss more than 12 months | Investment	237	85
U.S. agency debentures
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 659,979	$ 622,445
Unrealized Gains	3,167	7,840
Unrealized Losses	(1,601)	(1,198)
Fair Value	661,545	629,087
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value of Investments, Less than 12 months	104,688	118,721
Unrealized Losses, Less than 12 months	(1,601)	(1,198)
Fair Value of Investments, 12 months or longer	0	0
Unrealized Losses, 12 months or longer	0	0
Fair Value of Investments	104,688	118,721
Unrealized Losses	(1,601)	(1,198)
Agency-issued mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	6,304,969	2,896,179
Unrealized Gains	4,854	6,919
Unrealized Losses	(43,528)	(24,526)
Fair Value	6,266,295	2,878,572
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value of Investments, Less than 12 months	4,270,377	1,801,861
Unrealized Losses, Less than 12 months	(34,092)	(23,558)
Fair Value of Investments, 12 months or longer	408,913	21,917
Unrealized Losses, 12 months or longer	(9,436)	(968)
Fair Value of Investments	4,679,290	1,823,778
Unrealized Losses	(43,528)	(24,526)
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,829,979	3,362,598
Unrealized Gains	23	788
Unrealized Losses	(54,372)	(31,274)
Fair Value	2,775,630	3,332,112
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value of Investments, Less than 12 months	1,011,709	2,729,889
Unrealized Losses, Less than 12 months	(13,631)	(25,723)
Fair Value of Investments, 12 months or longer	1,741,614	228,220
Unrealized Losses, 12 months or longer	(40,741)	(5,551)
Fair Value of Investments	2,753,323	2,958,109
Unrealized Losses	(54,372)	(31,274)
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	255,782	312,665
Unrealized Gains	733	176
Unrealized Losses	(34)	(1,339)
Fair Value	256,481	311,502
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value of Investments, Less than 12 months	0	251,012
Unrealized Losses, Less than 12 months	0	(1,339)
Fair Value of Investments, 12 months or longer	9,812	0
Unrealized Losses, 12 months or longer	(34)	0
Fair Value of Investments	9,812	251,012
Unrealized Losses	(34)	(1,339)
Agency-issued commercial mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,868,985	1,151,363
Unrealized Gains	694	1,237
Unrealized Losses	(25,563)	(7,638)
Fair Value	1,844,116	1,144,962
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value of Investments, Less than 12 months	979,361	999,440
Unrealized Losses, Less than 12 months	(11,566)	(7,494)
Fair Value of Investments, 12 months or longer	773,712	14,934
Unrealized Losses, 12 months or longer	(13,997)	(144)
Fair Value of Investments	1,753,073	1,014,374
Unrealized Losses	(25,563)	(7,638)
Municipal bonds and notes
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	743,761	81,748
Unrealized Gains	3,452	8
Unrealized Losses	(3,000)	(1,853)
Fair Value	744,213	79,903
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value of Investments, Less than 12 months	344,796	42,267
Unrealized Losses, Less than 12 months	(2,103)	(877)
Fair Value of Investments, 12 months or longer	32,844	30,586
Unrealized Losses, 12 months or longer	(897)	(976)
Fair Value of Investments	377,640	72,853
Unrealized Losses	$ (3,000)	$ (1,853)

Investment Securities - Summa83

Investment Securities - Summary of Remaining Contractual Principal Maturities and Fully Taxable Equivalent Yields on Debt Securities Classified as Held to Maturity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 12,663,455	$ 8,426,998
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	12,663,455	8,426,998
Held-to-maturity Securities, Fair Value	12,548,280	8,376,138
Held-to-maturity securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	12,663,455
Held-to-maturity Securities, Fair Value	12,548,280
One Year or Less - Amortized Cost	7,801
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	7,777
One Year to Five Years - Amortized Cost	402,547
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	400,149
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	1,310,124
After Five Years to Ten Years - Amortized Cost	1,298,829
After Ten Years - Amortized Cost	10,942,983
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	$ 10,841,525
Held-to-maturity securities | Lower Limit
Schedule of Held-to-maturity Securities [Line Items]
Mortgage-backed securities contractual maturities (in years)	10 years
Held-to-maturity securities | Upper Limit
Schedule of Held-to-maturity Securities [Line Items]
Mortgage-backed securities contractual maturities (in years)	30 years
U.S. agency debentures
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	$ 659,979	622,445
Held-to-maturity Securities, Fair Value	661,545	629,087
U.S. agency debentures | Held-to-maturity securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	659,979
Held-to-maturity Securities, Fair Value	661,545
One Year or Less - Amortized Cost	0
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	0
One Year to Five Years - Amortized Cost	102,496
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	102,739
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	557,483
After Five Years to Ten Years - Amortized Cost	558,806
After Ten Years - Amortized Cost	0
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	0
Agency-issued mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	6,304,969	2,896,179
Held-to-maturity Securities, Fair Value	6,266,295	2,878,572
Agency-issued mortgage-backed securities | Held-to-maturity securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	6,304,969
Held-to-maturity Securities, Fair Value	6,266,295
One Year or Less - Amortized Cost	728
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	723
One Year to Five Years - Amortized Cost	226,997
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	225,149
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	56,380
After Five Years to Ten Years - Amortized Cost	55,697
After Ten Years - Amortized Cost	6,020,864
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	5,984,726
Residential mortgage-backed securities | Held-to-maturity securities | Agency-issued collateralized mortgage obligations | Fixed rate
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	2,829,979
One Year or Less - Amortized Cost	0
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	0
One Year to Five Years - Amortized Cost	0
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	0
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	462,533
After Five Years to Ten Years - Amortized Cost	451,069
After Ten Years - Amortized Cost	2,367,446
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	2,324,561
Residential mortgage-backed securities | Held-to-maturity securities | Agency-issued collateralized mortgage obligations | Variable rate
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	255,782
One Year or Less - Amortized Cost	0
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	0
One Year to Five Years - Amortized Cost	0
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	0
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	0
After Five Years to Ten Years - Amortized Cost	0
After Ten Years - Amortized Cost	255,782
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	256,481
Agency-issued commercial mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	1,868,985	1,151,363
Held-to-maturity Securities, Fair Value	1,844,116	1,144,962
Agency-issued commercial mortgage-backed securities | Held-to-maturity securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	1,868,985
Held-to-maturity Securities, Fair Value	1,844,116
One Year or Less - Amortized Cost	0
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	0
One Year to Five Years - Amortized Cost	0
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	0
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	0
After Five Years to Ten Years - Amortized Cost	0
After Ten Years - Amortized Cost	1,868,985
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	1,844,116
Municipal bonds and notes
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	743,761	81,748
Held-to-maturity Securities, Fair Value	744,213	79,903
Municipal bonds and notes | Held-to-maturity securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	743,761
Held-to-maturity Securities, Fair Value	744,213
One Year or Less - Amortized Cost	7,073
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	7,054
One Year to Five Years - Amortized Cost	73,054
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	72,261
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	233,728
After Five Years to Ten Years - Amortized Cost	233,257
After Ten Years - Amortized Cost	429,906
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	431,641
Variable rate | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	255,782	312,665
Held-to-maturity Securities, Fair Value	256,481	311,502
Variable rate | Residential mortgage-backed securities | Held-to-maturity securities | Agency-issued collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Fair Value	256,481
Fixed rate | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	2,829,979	3,362,598
Held-to-maturity Securities, Fair Value	2,775,630	$ 3,332,112
Fixed rate | Residential mortgage-backed securities | Held-to-maturity securities | Agency-issued collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Fair Value	$ 2,775,630

Investment Securities - Non-mar

Investment Securities - Non-marketable and Other Securities (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)Investment	Dec. 31, 2016USD ($)Investment	Dec. 31, 2015USD ($)Investment
Investment Holdings [Line Items]
Non-marketable securities	$ 89,809	$ 82,823
Amortization method qualified affordable housing project investments	174,214	112,447
Total non-marketable and other securities	651,053	622,552
Qualified Affordable Housing Project Investments, Commitment	100,891	58,095
Tax Credits And Other Tax Benefits Recognized	17,296	15,404	$ 14,375
Amortization Expense Included In Provision For Income Taxes	17,362	$ 12,145	$ 10,389
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 33,800
Upper Limit
Investment Holdings [Line Items]
Ownership interest percentage	5.00%	5.00%
Venture capital and private equity fund investments | Fair value accounting
Investment Holdings [Line Items]
Non-marketable securities	$ 127,192	$ 141,649
Non-marketable securities	202,000	222,000
Venture capital and private equity fund investments | Fair value accounting | Strategic Investors Fund, L.P.
Investment Holdings [Line Items]
Non-marketable securities	$ 14,673	$ 18,459
Ownership percentage of each Fund	12.60%	12.60%
Venture capital and private equity fund investments | Fair value accounting | CP II, L.P. | Direct ownership interest
Investment Holdings [Line Items]
Ownership percentage of each Fund	1.30%
Venture capital and private equity fund investments | Fair value accounting | CP II, L.P. | Indirect ownership interest
Investment Holdings [Line Items]
Ownership percentage of each Fund	3.80%
Venture capital and private equity fund investments | Fair value accounting | Capital Preferred Return Fund, L.P.
Investment Holdings [Line Items]
Non-marketable securities	$ 54,147	$ 57,627
Ownership percentage of each Fund	20.00%	20.00%
Venture capital and private equity fund investments | Fair value accounting | Growth Partners, L.P.
Investment Holdings [Line Items]
Non-marketable securities	$ 58,372	$ 59,718
Ownership percentage of each Fund	33.00%	33.00%
Venture capital and private equity fund investments | Fair value accounting | Other private equity fund
Investment Holdings [Line Items]
Non-marketable securities	$ 0	$ 5,845
Ownership percentage of each Fund	0.00%	58.20%
Venture capital and private equity fund investments | Equity method accounting
Investment Holdings [Line Items]
Non-marketable securities	$ 89,809	$ 82,823
Venture capital and private equity fund investments | Equity method accounting | Strategic Investors Fund II, L.P.
Investment Holdings [Line Items]
Non-marketable securities	$ 6,342	$ 7,720
Ownership percentage of each Fund	8.60%	8.60%
Venture capital and private equity fund investments | Equity method accounting | Strategic Investors Fund III, L.P.
Investment Holdings [Line Items]
Non-marketable securities	$ 18,758	$ 20,449
Ownership percentage of each Fund	5.90%	5.90%
Venture capital and private equity fund investments | Equity method accounting | Strategic Investors Fund IV, L.P.
Investment Holdings [Line Items]
Non-marketable securities	$ 25,551	$ 24,530
Ownership percentage of each Fund	5.00%	5.00%
Venture capital and private equity fund investments | Equity method accounting | Strategic Investors Fund V Funds
Investment Holdings [Line Items]
Non-marketable securities	$ 16,856	$ 12,029
Venture capital and private equity fund investments | Equity method accounting | CP II, L.P.
Investment Holdings [Line Items]
Non-marketable securities	$ 6,700	$ 7,798
Ownership percentage of each Fund	5.10%	5.10%
Venture capital and private equity fund investments | Equity method accounting | Other investments
Investment Holdings [Line Items]
Non-marketable securities	$ 15,602	$ 10,297
Venture capital and private equity fund investments | Cost method accounting
Investment Holdings [Line Items]
Non-marketable securities	$ 99,000	$ 115,000
Number of investments | Investment	235	252	267
Other venture capital investments | Fair value accounting
Investment Holdings [Line Items]
Non-marketable securities	$ 919	$ 2,040
Other venture capital investments | Fair value accounting | CP I, L.P.
Investment Holdings [Line Items]
Non-marketable securities	$ 919	$ 2,040
Ownership percentage of each Fund	10.70%	10.70%
Debt Securities | Equity method accounting
Investment Holdings [Line Items]
Non-marketable securities	$ 21,183	$ 17,020
Debt Securities | Equity method accounting | Gold Hill Capital 2008, LP
Investment Holdings [Line Items]
Non-marketable securities	$ 18,690	$ 13,557
Ownership percentage of each Fund	15.50%	15.50%
Debt Securities | Equity method accounting | Other investments
Investment Holdings [Line Items]
Non-marketable securities	$ 2,493	$ 3,463
Other investments | Fair value accounting | Capital Preferred Return Fund, L.P. | Indirect ownership interest
Investment Holdings [Line Items]
Ownership percentage of each Fund		4.10%
Other investments | Fair value accounting | Growth Partners, L.P. | Indirect ownership interest
Investment Holdings [Line Items]
Ownership percentage of each Fund		12.60%
Other investments | Fair value accounting | Other private equity fund | Direct ownership interest
Investment Holdings [Line Items]
Ownership percentage of each Fund		41.50%
Other investments | Equity method accounting
Investment Holdings [Line Items]
Non-marketable securities	$ 111,198	$ 123,514
Other investments | Equity method accounting | Gold Hill Capital 2008, LP | Direct ownership interest
Investment Holdings [Line Items]
Ownership percentage of each Fund	11.50%
Other investments | Equity method accounting | Gold Hill Capital 2008, LP | Indirect ownership interest
Investment Holdings [Line Items]
Ownership percentage of each Fund	4.00%
Other investments | Equity method accounting | China Joint Venture investment
Investment Holdings [Line Items]
Non-marketable securities	$ 75,337	$ 75,296
Ownership percentage of each Fund	50.00%	50.00%
Other investments | Equity method accounting | Other investments
Investment Holdings [Line Items]
Non-marketable securities	$ 35,861	$ 48,218
Other investments | Cost method accounting
Investment Holdings [Line Items]
Non-marketable securities	27,680	27,700
Low Income Housing Tax Credit Funds
Investment Holdings [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	3,800
Other securities | Fair value accounting
Investment Holdings [Line Items]
Non-marketable securities	$ 310	$ 753

Investment Securities - Compone

Investment Securities - Components of Gains and Losses (Realized and Unrealized) on Investment Securities (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2016USD ($)Investment	Dec. 31, 2017USD ($)Investment	Dec. 31, 2016USD ($)Investment	Dec. 31, 2015USD ($)Investment
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		$ 96,992,000	$ 87,500,000	$ 107,886,000
Gross losses on investment securities		(32,389,000)	(35,760,000)	(18,441,000)
Gains on investment securities, net		64,603,000	51,740,000	89,445,000
Other than Temporary Impairment Losses, Investments		$ 0	$ 0	$ 0
Cost method accounting | Venture capital and private equity fund investments
Gain (Loss) on Investments [Line Items]
Number of other-than-temporary impaired investments | Investment	26	24		22
Number of investments | Investment		235	252	267
Cost-method Investments, Other than Temporary Impairment	$ 600,000	$ 1,300,000		$ 600,000
Available-for-sale Securities
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Gross Realized Gains		5,113,000	$ 15,051,000	2,971,000
Available-for-sale Securities, Gross Realized Losses		(10,302,000)	(2,856,000)	(1,770,000)
Non-marketable securities | Fair value accounting | Venture capital and private equity fund investments
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		34,093,000	25,041,000	32,399,000
Gross losses on investment securities		(6,907,000)	(19,077,000)	(9,210,000)
Non-marketable securities | Fair value accounting | Other venture capital investments
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		1,114,000	17,000	1,512,000
Gross losses on investment securities		(143,000)	(38,000)	(320,000)
Non-marketable securities | Fair value accounting | Other securities
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		991,000	691,000	9,180,000
Gross losses on investment securities		(750,000)	(781,000)	(1,559,000)
Non-marketable securities | Equity method accounting | Venture capital and private equity fund investments
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		15,013,000	10,834,000	26,415,000
Gross losses on investment securities		(541,000)	(6,764,000)	(909,000)
Non-marketable securities | Equity method accounting | Debt Securities
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		11,658,000	1,406,000	4,111,000
Gross losses on investment securities		(2,708,000)	(458,000)	(774,000)
Non-marketable securities | Equity method accounting | Other investments
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		3,181,000	15,739,000	2,791,000
Gross losses on investment securities		(9,457,000)	(4,857,000)	(3,146,000)
Non-marketable securities | Cost method accounting | Venture capital and private equity fund investments
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		21,718,000	18,428,000	25,908,000
Gross losses on investment securities		(1,312,000)	(591,000)	(729,000)
Non-marketable securities | Cost method accounting | Other investments
Gain (Loss) on Investments [Line Items]
Gross gains on investment securities		4,111,000	293,000	2,599,000
Gross losses on investment securities		$ (269,000)	$ (338,000)	$ (24,000)

Loans and Allowance for Loan 86

Loans and Allowance for Loan Losses - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Deferred loan fee income	$ 148,000	$ 125,000
Loans modified in TDRs	147,793	96,059
Unfunded commitments available for funding	600
Loans modified in TDRs during the period	$ 93,843	$ 41,545	$ 110,371

Loans and Allowance for Loan 87

Loans and Allowance for Loan Losses - Composition of Loans, Net of Unearned Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 23,106,316	$ 19,899,944
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	20,476,830	17,731,612
Commercial loans | Software and internet
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	6,172,531	5,627,031
Commercial loans | Hardware
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,193,599	1,180,398
Commercial loans | Private equity/venture capital
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	9,952,377	7,691,148
Commercial loans | Life science/healthcare
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,808,827	1,853,004
Commercial loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	873,158	878,322
Commercial loans | Commercial Other Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	365,724	393,551
Commercial loans | Commercial Loans Receivable excluding Construction and Real Estate Secured
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	19,697,163	16,945,288
Commercial loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	476,338	501,709
Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	3,011,627	2,648,621
Real estate secured loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	669,053	678,166
Real estate secured loans | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,300,506	1,926,968
Real estate secured loans | Other Real Estate Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	42,068	43,487
Construction Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	68,546	64,671
Consumer loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	328,980	241,364
Consumer loans | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,300,506	1,926,968
Non-real Estate Secured Commercial Loans | Commercial loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	204,105	200,156
Loans for personal residence | Consumer loans | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,995,840	1,655,349
Loans to eligible employees | Consumer loans | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	243,118	199,291
Home equity lines of credit | Consumer loans | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 61,548	$ 72,328

Loans and Allowance for Loan 88

Loans and Allowance for Loan Losses - Composition of Loans, Net of Unearned Income (Footnote Information) (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Credit card receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit card loans	$ 270	$ 224
Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross construction loans	$ 100	$ 110

Loans and Allowance for Loan 89

Loans and Allowance for Loan Losses - Composition of Loans, Net of Unearned Income, Broken Out by Portfolio Segment and Class of Financing Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	$ 23,106,316	$ 19,899,944
Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	2,629,486	2,168,332
Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	20,476,830	17,731,612
Commercial loans | Software and internet
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	6,172,531	5,627,031
Commercial loans | Hardware
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	1,193,599	1,180,398
Commercial loans | Private equity/venture capital
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	9,952,377	7,691,148
Commercial loans | Life science/healthcare
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	1,808,827	1,853,004
Commercial loans | Premium wine
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	873,158	878,322
Commercial loans | Other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	476,338	501,709
Consumer loans | Other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	328,980	241,364
Consumer loans | Real estate secured consumer loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income	$ 2,300,506	$ 1,926,968

Loans and Allowance for Loan 90

Loans and Allowance for Loan Losses - Aging of Gross Loans, Broken out by Portfolio Segment and Class of Financing Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	$ 199,927	$ 98,292
Current	23,054,226	19,926,370
Loans Past Due 90 Days or More Still Accruing Interest	191	33
Total gross loans excluding impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	156,278	49,025
Current	22,923,014	19,741,177
Loans Past Due 90 Days or More Still Accruing Interest	191	33
Impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	43,649	49,267
Current	131,212	185,193
Loans Past Due 90 Days or More Still Accruing Interest	0	0
30 - 59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	111,525	81,575
30 - 59 Days Past Due | Total gross loans excluding impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	110,181	46,939
30 - 59 Days Past Due | Impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	1,344	34,636
60 - 89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	57,808	5,504
60 - 89 Days Past Due | Total gross loans excluding impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	45,906	2,053
60 - 89 Days Past Due | Impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	11,902	3,451
Equal to or Greater Than 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	30,594	11,213
Equal to or Greater Than 90 Days Past Due | Total gross loans excluding impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	191	33
Equal to or Greater Than 90 Days Past Due | Impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	30,403	11,180
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	152,786	46,773
Current	20,302,800	17,580,558
Loans Past Due 90 Days or More Still Accruing Interest	191	33
Commercial loans | Software and internet
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	20,924	38,255
Current	6,101,147	5,507,575
Loans Past Due 90 Days or More Still Accruing Interest	141	6
Commercial loans | Hardware
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	1,272	5,654
Current	1,163,278	1,118,065
Loans Past Due 90 Days or More Still Accruing Interest	50	27
Commercial loans | Private equity/venture capital
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	125,146	689
Current	9,835,317	7,747,222
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Commercial loans | Life science/healthcare
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	4,581	834
Current	1,841,692	1,827,490
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Commercial loans | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	418	1,007
Current	871,074	876,185
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Commercial loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	445	334
Current	490,292	504,021
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Commercial loans | 30 - 59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	107,221	44,687
Commercial loans | 30 - 59 Days Past Due | Software and internet
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	14,257	37,087
Commercial loans | 30 - 59 Days Past Due | Hardware
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	1,145	5,591
Commercial loans | 30 - 59 Days Past Due | Private equity/venture capital
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	86,566	689
Commercial loans | 30 - 59 Days Past Due | Life science/healthcare
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	4,390	283
Commercial loans | 30 - 59 Days Past Due | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	418	1,003
Commercial loans | 30 - 59 Days Past Due | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	445	34
Commercial loans | 60 - 89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	45,374	2,053
Commercial loans | 60 - 89 Days Past Due | Software and internet
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	6,526	1,162
Commercial loans | 60 - 89 Days Past Due | Hardware
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	77	36
Commercial loans | 60 - 89 Days Past Due | Private equity/venture capital
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	38,580	0
Commercial loans | 60 - 89 Days Past Due | Life science/healthcare
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	191	551
Commercial loans | 60 - 89 Days Past Due | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	4
Commercial loans | 60 - 89 Days Past Due | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	300
Commercial loans | Equal to or Greater Than 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	191	33
Commercial loans | Equal to or Greater Than 90 Days Past Due | Software and internet
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	141	6
Commercial loans | Equal to or Greater Than 90 Days Past Due | Hardware
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	50	27
Commercial loans | Equal to or Greater Than 90 Days Past Due | Private equity/venture capital
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	0
Commercial loans | Equal to or Greater Than 90 Days Past Due | Life science/healthcare
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	0
Commercial loans | Equal to or Greater Than 90 Days Past Due | Premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	0
Commercial loans | Equal to or Greater Than 90 Days Past Due | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	0
Consumer, Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	3,492	2,252
Current	2,620,214	2,160,619
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Consumer, Other | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	796	1,402
Consumer, Other | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	2,696	850
Current	2,292,980	1,923,266
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Consumer, Other | Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	327,234	237,353
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Consumer, Other | 30 - 59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	2,960	2,252
Consumer, Other | 30 - 59 Days Past Due | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	2,164	850
Consumer, Other | 30 - 59 Days Past Due | Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	796	1,402
Consumer, Other | 60 - 89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	532	0
Consumer, Other | 60 - 89 Days Past Due | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	532	0
Consumer, Other | 60 - 89 Days Past Due | Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	0
Consumer, Other | Equal to or Greater Than 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	0
Consumer, Other | Equal to or Greater Than 90 Days Past Due | Real estate secured consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	0	0
Consumer, Other | Equal to or Greater Than 90 Days Past Due | Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	$ 0	$ 0

Loans and Allowance for Loan 91

Loans and Allowance for Loan Losses - Impaired Loans and Allowance for Loan Losses, Broken out by Portfolio Segment and Class of Financing Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 174,861	$ 234,460
Impaired Financing Receivable, Unpaid Principal Balance	205,295	250,692
Impaired Financing Receivables With Related Allowance
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	88,246	233,370
Impaired Financing Receivables With No Related Allowance
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	86,615	1,090
Commercial loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	172,258	230,558
Impaired Financing Receivable, Unpaid Principal Balance	201,147	245,515
Commercial loans | Software and internet
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	110,654	122,748
Impaired Financing Receivable, Unpaid Principal Balance	129,006	129,648
Commercial loans | Hardware
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	36,350	65,395
Impaired Financing Receivable, Unpaid Principal Balance	41,721	70,683
Commercial loans | Private equity/venture capital
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	658	0
Impaired Financing Receivable, Unpaid Principal Balance	984	0
Commercial loans | Life science/healthcare
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	21,687	38,361
Impaired Financing Receivable, Unpaid Principal Balance	26,360	41,130
Commercial loans | Premium wine
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	2,877	3,187
Impaired Financing Receivable, Unpaid Principal Balance	2,911	3,187
Commercial loans | Other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	32	867
Impaired Financing Receivable, Unpaid Principal Balance	165	867
Commercial loans | Impaired Financing Receivables With Related Allowance
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	86,493	229,468
Commercial loans | Impaired Financing Receivables With Related Allowance | Software and internet
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	49,645	121,658
Commercial loans | Impaired Financing Receivables With Related Allowance | Hardware
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	15,637	65,395
Commercial loans | Impaired Financing Receivables With Related Allowance | Private equity/venture capital
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	658	0
Commercial loans | Impaired Financing Receivables With Related Allowance | Life science/healthcare
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	20,521	38,361
Commercial loans | Impaired Financing Receivables With Related Allowance | Premium wine
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	0	3,187
Commercial loans | Impaired Financing Receivables With Related Allowance | Other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	32	867
Commercial loans | Impaired Financing Receivables With No Related Allowance
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	85,765	1,090
Commercial loans | Impaired Financing Receivables With No Related Allowance | Software and internet
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	61,009	1,090
Commercial loans | Impaired Financing Receivables With No Related Allowance | Hardware
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	20,713	0
Commercial loans | Impaired Financing Receivables With No Related Allowance | Private equity/venture capital
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	0	0
Commercial loans | Impaired Financing Receivables With No Related Allowance | Life science/healthcare
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	1,166	0
Commercial loans | Impaired Financing Receivables With No Related Allowance | Premium wine
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	2,877	0
Commercial loans | Impaired Financing Receivables With No Related Allowance | Other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	0	0
Consumer loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	2,603	3,902
Impaired Financing Receivable, Unpaid Principal Balance	4,148	5,177
Consumer loans | Real estate secured consumer loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	2,181	1,504
Impaired Financing Receivable, Unpaid Principal Balance	3,712	2,779
Consumer loans | Other Loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	422	2,398
Impaired Financing Receivable, Unpaid Principal Balance	436	2,398
Consumer loans | Impaired Financing Receivables With Related Allowance
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	1,753	3,902
Consumer loans | Impaired Financing Receivables With Related Allowance | Real estate secured consumer loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	1,331	1,504
Consumer loans | Impaired Financing Receivables With Related Allowance | Other Loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	422	2,398
Consumer loans | Impaired Financing Receivables With No Related Allowance
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	850	0
Consumer loans | Impaired Financing Receivables With No Related Allowance | Real estate secured consumer loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	850	0
Consumer loans | Impaired Financing Receivables With No Related Allowance | Other Loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 0	$ 0

Loans and Allowance for Loan 92

Loans and Allowance for Loan Losses - Average Impaired Loans, Broken out by Portfolio Segment and Class of Financing Receivable (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Average impaired loans	$ 193,120	$ 176,412	$ 95,188
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	3,566	3,884	1,070
Commercial loans
Financing Receivable, Impaired [Line Items]
Average impaired loans	189,802	174,688	94,975
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	3,566	3,867	1,070
Commercial loans | Software and internet
Financing Receivable, Impaired [Line Items]
Average impaired loans	119,557	89,462	63,825
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	2,263	1,054	344
Commercial loans | Hardware
Financing Receivable, Impaired [Line Items]
Average impaired loans	35,022	39,108	8,854
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,061	2,624	574
Commercial loans | Private equity/venture capital
Financing Receivable, Impaired [Line Items]
Average impaired loans	556	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0	0
Commercial loans | Life science/healthcare
Financing Receivable, Impaired [Line Items]
Average impaired loans	30,842	40,620	18,083
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	90	155	132
Commercial loans | Premium wine
Financing Receivable, Impaired [Line Items]
Average impaired loans	3,249	2,056	1,455
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	152	28	12
Commercial loans | Other
Financing Receivable, Impaired [Line Items]
Average impaired loans	576	3,442	2,758
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	6	8
Consumer loans
Financing Receivable, Impaired [Line Items]
Average impaired loans	3,318	1,724	213
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	17	0
Consumer loans | Real estate secured consumer loans
Financing Receivable, Impaired [Line Items]
Average impaired loans	1,514	588	172
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0	0
Consumer loans | Other Loans
Financing Receivable, Impaired [Line Items]
Average impaired loans	1,804	1,136	41
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	$ 0	$ 17	$ 0

Loans and Allowance for Loan 93

Loans and Allowance for Loan Losses - Activity in Allowance for Loan Losses Broken out by Portfolio Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	$ 225,366	$ 217,613	$ 165,359
Charge-offs	(66,682)	(96,857)	(50,968)
Recoveries	8,538	12,212	6,209
Provision for loan losses	85,939	95,697	97,629
Allowance for Loan and Lease Losses, Foreign Currency Translation	1,863	(3,299)	(616)
Ending Balance	255,024	225,366	217,613
Software and internet
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		103,045	80,981
Charge-offs			(33,246)
Recoveries			1,621
Provision for loan losses			53,696
Ending Balance			103,045
Hardware
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		23,085	25,860
Charge-offs			(5,145)
Recoveries			3,332
Provision for loan losses			(1,035)
Ending Balance			23,085
Private equity/venture capital
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		35,282	27,997
Charge-offs			0
Recoveries			0
Provision for loan losses			7,391
Ending Balance			35,282
Life science/healthcare
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		36,576	15,208
Charge-offs			(7,291)
Recoveries			277
Provision for loan losses			28,400
Ending Balance			36,576
Premium wine
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		5,205	4,473
Charge-offs			0
Recoveries			7
Provision for loan losses			725
Ending Balance			5,205
Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		4,252	3,253
Charge-offs			(4,990)
Recoveries			809
Provision for loan losses			5,736
Ending Balance			4,252
Commercial loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	213,182	207,445	157,772
Charge-offs	(65,115)	(96,755)	(50,672)
Recoveries	7,175	11,954	6,046
Provision for loan losses	81,553	93,885	94,913
Ending Balance	238,583	213,182	207,445
Commercial loans | Software and internet
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	97,388	103,045
Charge-offs	(45,012)	(68,784)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	4,649	7,278
Provision for loan losses	38,462	58,350
Allowance for Loan and Lease Losses, Foreign Currency Translation	617	(2,501)	(7)
Ending Balance	96,104	97,388	103,045
Commercial loans | Hardware
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	31,166	23,085
Charge-offs	(10,414)	(13,233)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	487	1,667
Provision for loan losses	6,051	20,851
Allowance for Loan and Lease Losses, Foreign Currency Translation	324	(1,204)	73
Ending Balance	27,614	31,166	23,085
Commercial loans | Private equity/venture capital
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	50,299	35,282
Charge-offs	(323)	0
Allowance for Loan and Lease Loss, Recovery of Bad Debts	0	0
Provision for loan losses	31,625	15,114
Allowance for Loan and Lease Losses, Foreign Currency Translation	867	(97)	(106)
Ending Balance	82,468	50,299	35,282
Commercial loans | Life science/healthcare
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	25,446	36,576
Charge-offs	(8,210)	(9,693)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	189	1,129
Provision for loan losses	7,414	(2,543)
Allowance for Loan and Lease Losses, Foreign Currency Translation	85	(23)	(18)
Ending Balance	24,924	25,446	36,576
Commercial loans | Premium wine
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	4,115	5,205
Charge-offs	0	0
Allowance for Loan and Lease Loss, Recovery of Bad Debts	0	0
Provision for loan losses	(540)	(1,260)
Allowance for Loan and Lease Losses, Foreign Currency Translation	(43)	170	0
Ending Balance	3,532	4,115	5,205
Commercial loans | Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	4,768	4,252
Charge-offs	(1,156)	(5,045)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	1,850	1,880
Provision for loan losses	(1,459)	3,373
Allowance for Loan and Lease Losses, Foreign Currency Translation	(62)	308	(556)
Ending Balance	3,941	4,768	4,252
Commercial loans | Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan and Lease Losses, Foreign Currency Translation	1,788	(3,347)	(614)
Consumer loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	12,184	10,168	7,587
Charge-offs			(296)
Recoveries			163
Provision for loan losses			2,716
Ending Balance	16,441	12,184	10,168
Consumer loans | Consumer Loan
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	12,184	10,168
Charge-offs	(1,567)	(102)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	1,363	258
Provision for loan losses	4,386	1,812
Allowance for Loan and Lease Losses, Foreign Currency Translation	$ 75	48	(2)
Ending Balance		$ 12,184	$ 10,168

Loans and Allowance for Loan 94

Loans and Allowance for Loan Losses - Allowance for Loan Losses Individually and Collectively Evaluated for Impairment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	$ 41,793	$ 48,825
Financing Receivable, Individually Evaluated for Impairment	174,861	234,460
Collectively Evaluated for Impairment	213,231	176,541
Financing Receivable, Collectively Evaluated for Impairment	22,931,455	19,665,484
Commercial loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	41,215	47,702
Financing Receivable, Individually Evaluated for Impairment	172,258	230,558
Collectively Evaluated for Impairment	197,368	165,480
Financing Receivable, Collectively Evaluated for Impairment	20,304,572	17,501,054
Commercial loans | Software and internet
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	23,088	28,245
Financing Receivable, Individually Evaluated for Impairment	110,654	122,748
Collectively Evaluated for Impairment	73,016	69,143
Financing Receivable, Collectively Evaluated for Impairment	6,061,877	5,504,283
Commercial loans | Hardware
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	8,450	9,995
Financing Receivable, Individually Evaluated for Impairment	36,350	65,395
Collectively Evaluated for Impairment	19,164	21,171
Financing Receivable, Collectively Evaluated for Impairment	1,157,249	1,115,003
Commercial loans | Private equity/venture capital
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	330	0
Financing Receivable, Individually Evaluated for Impairment	658	0
Collectively Evaluated for Impairment	82,138	50,299
Financing Receivable, Collectively Evaluated for Impairment	9,951,719	7,691,148
Commercial loans | Life science/healthcare
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	9,315	8,709
Financing Receivable, Individually Evaluated for Impairment	21,687	38,361
Collectively Evaluated for Impairment	15,609	16,737
Financing Receivable, Collectively Evaluated for Impairment	1,787,140	1,814,643
Commercial loans | Premium wine
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	0	520
Financing Receivable, Individually Evaluated for Impairment	2,877	3,187
Collectively Evaluated for Impairment	3,532	3,595
Financing Receivable, Collectively Evaluated for Impairment	870,281	875,135
Commercial loans | Other
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	32	233
Financing Receivable, Individually Evaluated for Impairment	32	867
Collectively Evaluated for Impairment	3,909	4,535
Financing Receivable, Collectively Evaluated for Impairment	476,306	500,842
Consumer loans | Consumer Loan
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	578	1,123
Financing Receivable, Individually Evaluated for Impairment	2,603	3,902
Collectively Evaluated for Impairment	15,863	11,061
Financing Receivable, Collectively Evaluated for Impairment	$ 2,626,883	$ 2,164,430

Loans and Allowance for Loan 95

Loans and Allowance for Loan Losses - Credit Quality Indicators, Broken out by Portfolio Segment and Class of Financing Receivables (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	$ 23,254,153	$ 20,024,662
Pass
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	22,357,492	18,864,595
Performing (Criticized)
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	721,800	925,607
Performing Impaired
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	55,602	115,481
Non Performing Impaired
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	119,259	118,979
Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	20,627,844	17,857,889
Commercial loans | Software and internet
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	6,232,725	5,668,578
Commercial loans | Hardware
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	1,200,900	1,189,114
Commercial loans | Private equity/venture capital
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	9,961,121	7,747,911
Commercial loans | Life science/healthcare
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	1,867,960	1,866,685
Commercial loans | Premium wine
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	874,369	880,379
Commercial loans | Other
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	490,769	505,222
Commercial loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	19,748,266	16,711,827
Commercial loans | Pass | Software and internet
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	5,655,739	4,924,923
Commercial loans | Pass | Hardware
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	1,112,574	985,889
Commercial loans | Pass | Private equity/venture capital
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	9,955,082	7,747,317
Commercial loans | Pass | Life science/healthcare
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	1,720,613	1,707,499
Commercial loans | Pass | Premium wine
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	834,537	865,354
Commercial loans | Pass | Other
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	469,721	480,845
Commercial loans | Performing (Criticized)
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	707,320	915,504
Commercial loans | Performing (Criticized) | Software and internet
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	466,332	620,907
Commercial loans | Performing (Criticized) | Hardware
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	51,976	137,830
Commercial loans | Performing (Criticized) | Private equity/venture capital
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	5,381	594
Commercial loans | Performing (Criticized) | Life science/healthcare
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	125,660	120,825
Commercial loans | Performing (Criticized) | Premium wine
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	36,955	11,838
Commercial loans | Performing (Criticized) | Other
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	21,016	23,510
Commercial loans | Performing Impaired
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	55,602	114,695
Commercial loans | Performing Impaired | Software and internet
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	31,794	46,143
Commercial loans | Performing Impaired | Hardware
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	20,165	58,814
Commercial loans | Performing Impaired | Private equity/venture capital
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	0	0
Commercial loans | Performing Impaired | Life science/healthcare
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	1,167	6,578
Commercial loans | Performing Impaired | Premium wine
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	2,476	2,696
Commercial loans | Performing Impaired | Other
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	0	464
Commercial loans | Non Performing Impaired
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	116,656	115,863
Commercial loans | Non Performing Impaired | Software and internet
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	78,860	76,605
Commercial loans | Non Performing Impaired | Hardware
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	16,185	6,581
Commercial loans | Non Performing Impaired | Private equity/venture capital
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	658	0
Commercial loans | Non Performing Impaired | Life science/healthcare
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	20,520	31,783
Commercial loans | Non Performing Impaired | Premium wine
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	401	491
Commercial loans | Non Performing Impaired | Other
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	32	403
Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	2,626,309	2,166,773
Consumer loans | Real estate secured consumer loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	2,297,857	1,925,620
Consumer loans | Other
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	328,452	241,153
Consumer loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	2,609,226	2,152,768
Consumer loans | Pass | Real estate secured consumer loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	2,282,375	1,914,512
Consumer loans | Pass | Other Loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	326,851	238,256
Consumer loans | Performing (Criticized)
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	14,480	10,103
Consumer loans | Performing (Criticized) | Real estate secured consumer loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	13,301	9,604
Consumer loans | Performing (Criticized) | Other Loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	1,179	499
Consumer loans | Performing Impaired
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	0	786
Consumer loans | Performing Impaired | Real estate secured consumer loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	0	0
Consumer loans | Performing Impaired | Other Loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	0	786
Consumer loans | Non Performing Impaired
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	2,603	3,116
Consumer loans | Non Performing Impaired | Real estate secured consumer loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	2,181	1,504
Consumer loans | Non Performing Impaired | Other Loans
Financing Receivable, Recorded Investment [Line Items]
Financing receivable	$ 422	$ 1,612

Loans and Allowance for Loan 96

Loans and Allowance for Loan Losses - Summary of Loans Modified in Troubled Debt Restructurings ("TDRs") by Portfolio Segment and Class of Financing Receivables (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)troubled_debt_restructuring	Dec. 31, 2016USD ($)troubled_debt_restructuring
Financing Receivable, Modifications [Line Items]
Number of TDRs | troubled_debt_restructuring	22	20
Loans modified in TDRs	$ 147,793	$ 96,059
Commercial loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	147,370	95,273
Commercial loans | Software and internet
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	73,455	52,646
Commercial loans | Hardware
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	51,132	14,870
Commercial loans | Private Equity And Venture Capital Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	350	0
Commercial loans | Life science/healthcare
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	19,235	24,176
Commercial loans | Premium wine
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	3,198	3,194
Commercial loans | Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	0	387
Consumer loans | Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	$ 423	$ 786

Loans and Allowance for Loan 97

Loans and Allowance for Loan Losses - Recorded Investment in Loans Modified in TDRs (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)troubled_debt_restructuring	Dec. 31, 2016USD ($)troubled_debt_restructuring	Dec. 31, 2015USD ($)
Financing Receivable, Modifications [Line Items]
Number of TDRs | troubled_debt_restructuring	22	20
Loans modified in TDRs during the period	$ 93,843	$ 41,545	$ 110,371
Partial charge-offs on loans classified as TDRs	3,000	3,600	23,500
Commercial loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	93,843	40,759	110,371
Commercial loans | Software and internet
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	42,184	23,574	56,790
Commercial loans | Hardware
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	51,132	14,870	286
Commercial loans | Private equity/venture capital
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	350	0	0
Commercial loans | Life science/healthcare
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	0	1,638	51,878
Commercial loans | Premium wine
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	177	677	898
Commercial loans | Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	0	0	519
Consumer loans | Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	0	$ 786	$ 0
Payment Deferrals Granted
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	93,500
Forgiveness Of Principal
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	$ 300

Loans and Allowance for Loan 98

Loans and Allowance for Loan Losses - Recorded Investment in Loans Modified in TDRs within Previous 12 months Subsequently Defaulted (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 0	$ 1,411	$ 18,033
Commercial loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	625	18,033
Commercial loans | Software and internet
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	0	16,804
Commercial loans | Hardware
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	134	286
Commercial loans | Premium wine
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	491	0
Commercial loans | Life science/healthcare
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	0	943
Consumer loans | Other
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 0	$ 786	$ 0

Loans and Allowance for Loan 99

Loans and Allowance for Loan Losses Activity in Allowance for Unfunded Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Activity in Allowance for Unfunded Commitments [Abstract]
Reserve For Unfunded Credit Commitments	$ 51,770	$ 45,265	$ 34,415	$ 36,419
Provision For Unfunded Credit Commitments	6,365	10,982	(1,946)
Foreign Currency Translation, Unfunded Credit Commitments	$ 140	$ (132)	$ (58)

Premises and Equipment Componen

Premises and Equipment Components of Premises and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Computer software	$ 203,359	$ 189,867
Computer hardware	63,881	56,215
Leasehold improvements	89,225	70,909
Furniture and equipment	38,146	31,886
Total	394,611	348,877
Accumulated depreciation and amortization	(265,929)	(228,194)
Premises and equipment, net	$ 128,682	$ 120,683

Premises and Equipment Addition

Premises and Equipment Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 38	$ 33.9	$ 28.3

Deposits Composition of Deposit

Deposits Composition of Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Noninterest-bearing demand deposits	$ 36,655,497	$ 31,975,457
Interest bearing checking and savings	556,121	375,710
Money market	5,975,220	5,331,054
Money market deposits in foreign offices	111,201	107,657
Sweep deposits in foreign offices	908,890	1,133,872
Time	47,146	56,118
Total deposits	$ 44,254,075	$ 38,979,868

Deposits Additional Information

Deposits Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Time Deposits, $250,000 or More	$ 37	$ 43
Time Deposit Maturities, Next Twelve Months	$ 37

Short-Term Borrowings and Lo104

Short-Term Borrowings and Long-Term Debt Outstanding Short Term Borrowings and Long Term Debt (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Jan. 29, 2015	Sep. 30, 2010	Oct. 30, 2003
Debt Outstanding [Line Items]
Short-term borrowings	$ 1,033,730,000	$ 512,668,000
Total long-term debt	$ 695,492,000	795,704,000
Federal Home Loan Bank Advances
Debt Outstanding [Line Items]
Maturity	Jan. 2, 2018
Principal value	$ 700,000,000
Federal Home Loan Bank Advances	$ 700,000,000	500,000,000
Federal Funds Purchased
Debt Outstanding [Line Items]
Maturity	Jan. 2, 2018
Principal value	$ 330,000,000
Short-term borrowings	330,000,000	0
Other short-term borrowings
Debt Outstanding [Line Items]
Principal value	3,730,000
Short-term borrowings	$ 3,730,000	12,668,000
3.50% Senior Notes
Debt Outstanding [Line Items]
Maturity	Jan. 29, 2025
Principal value	$ 350,000,000		$ 350,000,000
Senior Notes	$ 347,303,000	346,979,000
5.375% Senior Notes
Debt Outstanding [Line Items]
Maturity	Sep. 15, 2020
Principal value	$ 350,000,000			$ 350,000,000
Senior Notes	$ 348,189,000	347,586,000
6.05% Subordinated Notes
Debt Outstanding [Line Items]
Maturity	Jun. 1, 2017
Principal value	$ 0
Subordinated Notes	0	46,646,000
7.0% Junior Subordinated Debentures
Debt Outstanding [Line Items]
Principal value	0				$ 50,000,000
Junior Subordinated Debentures	$ 0	$ 54,493,000

Short-Term Borrowings and Lo105

Short-Term Borrowings and Long-Term Debt Outstanding Short Term Borrowings and Long Term Debt (Additional Information) (Detail) - USD ($)	Jan. 29, 2015	Sep. 30, 2010	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 15, 2007	Oct. 30, 2003
Debt Outstanding [Line Items]
Weighted average interest rates associated with short-term borrowings			1.39%	0.59%
Proceeds from issuance of 3.50% Senior Notes			$ 0	$ 0	$ 346,431,000
3.50% Senior Notes
Debt Outstanding [Line Items]
Stated interest rate			3.50%	3.50%
Principal value	$ 350,000,000		$ 350,000,000
Maturity			Jan. 29, 2025
Proceeds from issuance of 3.50% Senior Notes	$ 346,400,000
Senior Notes			$ 347,303,000	$ 346,979,000
Deferred Finance Costs, Gross			3,000,000
Debt Instrument, Unamortized Discount			$ 300,000
5.375% Senior Notes
Debt Outstanding [Line Items]
Stated interest rate			5.375%	5.375%
Principal value		$ 350,000,000	$ 350,000,000
Maturity			Sep. 15, 2020
Proceeds from issuance of 3.50% Senior Notes		$ 345,000,000
Senior Notes			$ 348,189,000	$ 347,586,000
6.05% Subordinated Notes
Debt Outstanding [Line Items]
Fair value of the interest rate swap associated with the notes				$ 800,000
Stated interest rate			6.05%	6.05%
Principal value			$ 0
Maturity			Jun. 1, 2017
Debt Instrument, Unamortized Discount						$ 250,000,000
6.05% Subordinated Notes | Interest rate swaps
Debt Outstanding [Line Items]
Fair value of the interest rate swap associated with the notes				$ 800,000
7.0% Junior Subordinated Debentures
Debt Outstanding [Line Items]
Stated interest rate			7.00%	7.00%
Principal value			$ 0				$ 50,000,000
Repayments of Debt			$ 51,500,000

Aggregate Annual Maturities of

Aggregate Annual Maturities of Long-Term Debt Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
2,018	$ 0
2,019	0
2,020	348,189
2,021	0
2,022	0
2023 and thereafter	347,303
Total	$ 695,492	$ 795,704

Short-Term Borrowings and Lo107

Short-Term Borrowings and Long-Term Debt - Additional Information (Detail) - USD ($)	Jan. 29, 2015	Sep. 30, 2010	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 15, 2007	Oct. 30, 2003
Debt Disclosure [Line Items]
Interest expense, debt											$ 36,100,000	$ 37,300,000	$ 34,900,000
Weighted average interest rates associated with short-term borrowings			1.39%				0.59%				1.39%	0.59%
Short-term borrowings			$ 1,033,730,000				$ 512,668,000				$ 1,033,730,000	$ 512,668,000
Proceeds from issuance of senior notes, net of discount and issuance cost											0	0	346,431,000
Interest expense			$ 11,310,000	$ 11,297,000	$ 11,231,000	$ 10,933,000	$ 10,728,000	$ 11,252,000	$ 10,656,000	$ 10,237,000	44,771,000	42,873,000	40,340,000
Special Purpose Trust Entity
Debt Disclosure [Line Items]
Interest expense											$ 3,300,000	$ 3,500,000	$ 3,500,000
3.50% Senior Notes
Debt Disclosure [Line Items]
Stated interest rate			3.50%				3.50%				3.50%	3.50%
Principal value	$ 350,000,000		$ 350,000,000								$ 350,000,000
Debt Instrument, Unamortized Discount			$ 300,000								$ 300,000
Maturity											Jan. 29, 2025
Proceeds from issuance of senior notes, net of discount and issuance cost	$ 346,400,000
5.375% Senior Notes
Debt Disclosure [Line Items]
Stated interest rate			5.375%				5.375%				5.375%	5.375%
Principal value		$ 350,000,000	$ 350,000,000								$ 350,000,000
Maturity											Sep. 15, 2020
Payments for settlement of 3.875% Convertible Notes		250,000,000
Proceeds from issuance of senior notes, net of discount and issuance cost		$ 345,000,000
6.05% Subordinated Notes
Debt Disclosure [Line Items]
Stated interest rate			6.05%				6.05%				6.05%	6.05%
Principal value			$ 0								$ 0
Debt Instrument, Unamortized Discount														$ 250,000,000
Maturity											Jun. 1, 2017
7.0% Junior Subordinated Debentures
Debt Disclosure [Line Items]
Stated interest rate			7.00%				7.00%				7.00%	7.00%
Principal value			$ 0								$ 0				$ 50,000,000
Debt issuance costs															$ 2,200,000
Federal Funds Purchased
Debt Disclosure [Line Items]
Principal value			330,000,000								$ 330,000,000
Maturity											Jan. 2, 2018
Short-term borrowings			330,000,000				$ 0				$ 330,000,000	$ 0
Federal Home Loan Bank Advances
Debt Disclosure [Line Items]
Principal value			700,000,000								$ 700,000,000
Maturity											Jan. 2, 2018
Market value of collateral pledged			3,400,000,000								$ 3,400,000,000
Unused and available funds			2,700,000,000								2,700,000,000
Federal Reserve Bank Advances
Debt Disclosure [Line Items]
Market value of collateral pledged			$ 1,000,000,000								$ 1,000,000,000

Derivative Financial Instrum108

Derivative Financial Instruments Total Notional or Contractual Amounts, Fair Value, Collateral and Net Exposure of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Fair value	$ 108,389	$ 78,947
Fair value	(108,581)	(64,438)
Net Exposure Derivative Instruments	119,841	132,964
Fair value	123,571	145,632
Collateral	3,730	12,668
Derivatives designated as hedging instruments | Interest rate risks | Other Assets
Derivative [Line Items]
Notional or Contractual Amount	0	45,964
Fair value	0	810
Collateral	0	89
Net Exposure	0	721
Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member]
Derivative [Line Items]
Fair value	(4,787)	2,089
Net Exposure Derivative Instruments	(4,826)	2,089
Collateral	39	0
Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other Assets
Derivative [Line Items]
Notional or Contractual Amount	50,889	219,950
Fair value	414	3,057
Collateral	39	0
Net Exposure	375	3,057
Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other liability
Derivative [Line Items]
Notional or Contractual Amount	425,055	54,338
Fair value	(5,201)	(968)
Net Exposure Derivative Instruments Liabilities	(5,201)	(968)
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Equity warrant assets | Other Assets
Derivative [Line Items]
Notional or Contractual Amount	211,253	211,434
Fair value	123,763	131,123
Collateral	0	0
Net Exposure	123,763	131,123
Derivatives not designated as hedging instruments | Other derivative instruments | Foreign Exchange Contract [Member] | Other Assets
Derivative [Line Items]
Notional or Contractual Amount	2,203,643	1,251,308
Fair value	95,035	54,587
Collateral	3,691	12,579
Net Exposure	91,344	42,008
Derivatives not designated as hedging instruments | Other derivative instruments | Foreign Exchange Contract [Member] | Other liability
Derivative [Line Items]
Notional or Contractual Amount	2,092,207	1,068,991
Fair value	(90,253)	(43,317)
Net Exposure Derivative Instruments Liabilities	(90,253)	(43,317)
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives
Derivative [Line Items]
Fair value	4,595	11,610
Net Exposure Derivative Instruments	904	(969)
Collateral	3,691	12,579
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Other Assets
Derivative [Line Items]
Notional or Contractual Amount	102,678	775,000
Fair value	1,187	10,383
Collateral	0	0
Net Exposure	1,187	10,383
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Other liability
Derivative [Line Items]
Notional or Contractual Amount	102,678	775,000
Fair value	(1,187)	(10,383)
Net Exposure Derivative Instruments Liabilities	(1,187)	(10,383)
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Client interest rate derivatives | Other Assets
Derivative [Line Items]
Notional or Contractual Amount	726,984	583,511
Fair value	11,753	10,110
Collateral	0	0
Net Exposure	11,753	10,110
Derivatives not designated as hedging instruments | Other derivative instruments | Client interest rate derivatives | Other liability
Derivative [Line Items]
Notional or Contractual Amount	782,586	627,639
Fair value	(11,940)	(9,770)
Net Exposure Derivative Instruments Liabilities	(11,940)	(9,770)
Collateral	$ 0	$ 0

Derivative Financial Instrum109

Derivative Financial Instruments Summary of Derivative Activity and Related Impact on Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity warrant assets
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	$ 11,862	$ 9,251	$ 54,678
Derivatives designated as hedging instruments | Interest rate risks
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	1,046	2,306	2,506
Derivatives designated as hedging instruments | Interest rate risks | Interest expense-borrowings
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	1,053	2,341	2,526
Derivatives designated as hedging instruments | Interest rate risks | Net gains on derivative instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	(7)	(35)	(20)
Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Net gains on derivative instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	(32,286)	16,136	12,377
Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	(9,969)
Derivatives not designated as hedging instruments | Other derivative instruments | Net gains on derivative instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	(9,969)	(5,674)	694
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Net gains on derivative instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	(564)	262	(209)
Derivatives not designated as hedging instruments | Equity warrant assets | gains and losses on equity warrant assets [Domain]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	54,555	37,892	70,963
Internal Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Transaction Gain (Loss), before Tax	33,161	(16,676)	(12,735)
Internal Instruments [Member] | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	875	(540)	(358)
Internal Instruments [Member] | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	(32,286)	16,136	12,377
Foreign Currency Transaction Gain (Loss), before Tax	33,161	(16,676)	(12,735)
Client Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Transaction Gain (Loss), before Tax	10,882	4,215	115
Client Instruments [Member] | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	913	(1,459)	809
Client Instruments [Member] | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives		(5,674)	694
Foreign Currency Transaction Gain (Loss), before Tax	$ 10,882	$ 4,215	$ 115

Derivative Financial Instrum110

Derivative Financial Instruments Master Netting Arrangements (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Offsetting Derivative Assets [Abstract]
Fair value	$ 108,389	$ 78,947
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset	108,389	78,947
Derivative, Collateral, Obligation to Return Securities	(26,754)	(42,356)
Derivative, Collateral, Obligation to Return Cash	(3,730)	(12,668)
Derivative Asset, Fair Value, Amount Offset Against Collateral	77,905	23,923
Offsetting Securities Purchased under Agreements to Resell [Abstract]
Securities Purchased under Agreements to Resell, Gross	247,876	64,028
Securities Purchased under Agreements to Resell, Liability	0	0
Securities Purchased under Agreements to Resell	247,876	64,028
Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Securities	(247,876)	(64,028)
Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Cash	0	0
Securities Purchased under Agreements to Resell, Amount Offset Against Collateral	0	0
Offsetting Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed [Abstract]
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Gross	356,265	142,975
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Liability	0	0
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed	356,265	142,975
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Collateral, Obligation to Return Securities	(274,630)	(106,384)
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Collateral, Obligation to Return Cash	(3,730)	(12,668)
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Amount Offset Against Collateral	77,905	23,923
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	(108,581)	(64,438)
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	108,581	64,438
Derivative, Collateral, Right to Reclaim Securities	92,662	29,319
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(15,919)	(35,119)
Offsetting Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase, Gross	0	0
Securities Sold under Agreements to Repurchase, Asset	0	0
Securities Sold under Agreements to Repurchase	0	0
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	0	0
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash	0	0
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral	0	0
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Gross	(108,581)	(64,438)
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Asset	0	0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned	(108,581)	(64,438)
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Securities	92,662	29,319
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Amount Offset Against Collateral	(15,919)	(35,119)
Interest rate swaps
Offsetting Derivative Assets [Abstract]
Fair value	0	810
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset	0	810
Derivative, Collateral, Obligation to Return Securities	0	(721)
Derivative, Collateral, Obligation to Return Cash	0	(89)
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Foreign exchange forwards
Offsetting Derivative Assets [Abstract]
Fair value	95,449	57,644
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset	95,449	57,644
Derivative, Collateral, Obligation to Return Securities	(14,456)	(22,738)
Derivative, Collateral, Obligation to Return Cash	(3,730)	(12,579)
Derivative Asset, Fair Value, Amount Offset Against Collateral	77,263	22,327
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	(95,454)	(44,285)
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	95,454	44,285
Derivative, Collateral, Right to Reclaim Securities	80,107	17,964
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(15,347)	(26,321)
Foreign currency options
Offsetting Derivative Assets [Abstract]
Fair value	1,187	10,383
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset	1,187	10,383
Derivative, Collateral, Obligation to Return Securities	(557)	(8,806)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	630	1,577
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	(1,187)	(10,383)
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	1,187	10,383
Derivative, Collateral, Right to Reclaim Securities	631	1,585
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(556)	(8,798)
Client interest rate derivatives
Offsetting Derivative Assets [Abstract]
Fair value	11,753	10,110
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset	11,753	10,110
Derivative, Collateral, Obligation to Return Securities	(11,741)	(10,091)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	12	19
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	(11,940)	(9,770)
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	11,940	9,770
Derivative, Collateral, Right to Reclaim Securities	11,924	9,770
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ (16)	$ 0

Noninterest Income Summary of N

Noninterest Income Summary of Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of noninterest income [Abstract]
Gains on investment securities, net									$ 64,603	$ 51,740	$ 89,445
Noninterest Income	$ 152,266	$ 158,778	$ 128,528	$ 117,659	$ 113,502	$ 144,140	$ 112,776	$ 86,134	557,231	456,552	472,794
Gains on derivative instruments, net									54,555	37,892	70,963
Foreign exchange fees									115,760	104,183	87,007
Credit card fees									76,543	68,205	56,657
Deposit service charges									58,715	52,524	46,683
Asset Management Fees									56,136	32,219	21,610
Fees and Commissions									43,265	33,395	32,536
Letters of credit and standby letters of credit fees									28,544	25,644	20,889
Other									$ 59,110	$ 50,750	$ 47,004

Noninterest Income Gains and Lo

Noninterest Income Gains and Losses on Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gains and Losses on Investments [Abstract]
Gains and Losses on Non-Marketable and Other Securities	$ 69,792	$ 39,545	$ 88,244
Marketable Securities, Realized Gain (Loss)	(5,189)	12,195	1,201
Gains on investment securities, net	$ 64,603	$ 51,740	$ 89,445

Noninterest Income Gains and113

Noninterest Income Gains and Losses on Derivatives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gains and Losses on Derivatives [Abstract]
Gains and Losses on Exercised Warrant Assets	$ 48,275	$ 31,197	$ 41,455
Losses on Terminated Equity Warrant Assets	(4,422)	(3,015)	(1,040)
Unrealized Gain (Loss) on Derivatives	10,702	9,710	30,548
Gains on derivative instruments, net	$ 54,555	$ 37,892	$ 70,963

Noninterest Income Foreign Exch

Noninterest Income Foreign Exchange Fees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gains and Losses on Derivatives [Abstract]
Brokerage Commissions Revenue	$ 104,344	$ 89,354	$ 80,564
Forward Contract Commissions	10,934	14,004	6,414
Option Premium Fees	482	825	29
Foreign exchange fees	$ 115,760	$ 104,183	$ 87,007

Noninterest Income Credit Card

Noninterest Income Credit Card Fees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gains and Losses on Derivatives [Abstract]
Fees and Commissions, Credit and Debit Cards	$ 60,224	$ 51,513	$ 46,185
Merchant Discount Fees	11,584	12,783	7,346
Fees and Commissions, Debit Cards	4,735	3,909	3,126
Credit card fees	$ 76,543	$ 68,205	$ 56,657

Noninterest Income Client Inves

Noninterest Income Client Investment Fees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gains and Losses on Derivatives [Abstract]
Sweep Money Market Fees	$ 28,485	$ 15,147	$ 9,347
Investment Advisory, Management and Administrative Fees	16,831	15,389	12,263
Sweep Repo Fees	10,820	1,683	0
Asset Management Fees	$ 56,136	$ 32,219	$ 21,610

Noninterest Income Lending Rela

Noninterest Income Lending Related Fees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gains and Losses on Derivatives [Abstract]
Line of Credit Facility, Commitment Fee Amount	$ 34,110	$ 25,654	$ 24,025
Fees and Commissions, Other	9,155	7,741	8,511
Fees and Commissions	$ 43,265	$ 33,395	$ 32,536

Noninterest Income Summary of O

Noninterest Income Summary of Other Noninterest Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Trading Activity, Gains and Losses, Net [Line Items]
Fund management fees	$ 21,214	$ 19,195	$ 15,941
Service-based fee income	3,860	7,962	8,767
Other	32,248	25,592	21,845
Other	59,110	50,750	47,004
Client Instruments [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Foreign Currency Transaction Gain (Loss), before Tax	10,882	4,215	115
Internal Instruments [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Foreign Currency Transaction Gain (Loss), before Tax	33,161	(16,676)	(12,735)
Derivatives not designated as hedging instruments | Client Instruments [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Unrealized Gain (Loss) on Derivatives	913	(1,459)	809
Other derivative instruments | Derivatives not designated as hedging instruments | Net gains on derivative instruments
Trading Activity, Gains and Losses, Net [Line Items]
Unrealized Gain (Loss) on Derivatives	(9,969)	(5,674)	694
Foreign Exchange Contract [Member] | Derivatives not designated as hedging instruments | Internal Instruments [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Unrealized Gain (Loss) on Derivatives	875	(540)	(358)
Foreign Exchange Contract [Member] | Derivatives not designated as hedging instruments | Net gains on derivative instruments
Trading Activity, Gains and Losses, Net [Line Items]
Unrealized Gain (Loss) on Derivatives	$ (32,286)	$ 16,136	$ 12,377

Other Noninterest Expense (Deta

Other Noninterest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other noninterest expense [Abstract]
Lending and other client related processing costs	$ 23,768	$ 19,867	$ 15,944
Telephone	10,647	9,793	9,398
Data processing services	10,251	9,014	7,316
Dues and publications	3,263	2,828	2,476
Postage and supplies	2,797	2,851	3,154
Other	21,419	17,890	19,999
Total other noninterest expense	$ 72,145	$ 62,243	$ 58,287

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Valuation allowance	$ (2,624)	$ (4,440)
Unrecognized tax benefit	12,683	5,711	$ 3,658	$ 3,497
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	8,900
Federal
Income Taxes [Line Items]
Operating Loss Carryforwards	3,000	4,000
Foreign Tax Authority
Income Taxes [Line Items]
Operating Loss Carryforwards	11,000	16,000
Unrecognized Tax Benefits Before Interest And Penalties
Income Taxes [Line Items]
Unrecognized tax benefit	$ 11,505	$ 5,269	$ 3,357	$ 3,397

Income Taxes Components of Prov

Income Taxes Components of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Current provision:
Federal									$ 263,231		$ 195,249	$ 191,194
State									67,046		59,319	50,815
Deferred expense (benefit):
Federal									24,654		(3,560)	(11,270)
State									532		(675)	(1,985)
Income tax expense	$ 135,051	$ 97,351	$ 71,656	$ 51,405	$ 54,825	$ 76,877	$ 65,047	$ 53,584	$ 355,463	[1]	$ 250,333	$ 228,754
[1]	Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted, for the year ended December 31, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update ("ASU") 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.

Income Taxes Reconciliation bet

Income Taxes Reconciliation between Federal Statutory Income Tax Rate and Effective Income Tax Rate (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 33.8
Federal statutory income tax rate	35.00%	35.00%	35.00%
State income taxes, net of the federal tax effect	5.80%	5.90%	5.70%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	4.30%	0.00%	0.00%
Meals and entertainment	0.30%	0.40%	0.30%
Disallowed officer's compensation	0.10%	0.10%	0.30%
Share-based compensation expense on incentive stock options and ESPP	(2.10%)	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.40%)	(0.50%)	(0.50%)
Tax-exempt interest income	(0.30%)	(0.20%)	(0.20%)
Valuation allowance benefit	0.00%	(0.30%)	(0.40%)
Other, net	(0.70%)	(0.90%)	(0.30%)
Effective income tax rate	42.00%	39.50%	39.90%

Income Taxes Deferred Tax (Liab

Income Taxes Deferred Tax (Liabilities) Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 33,800
Deferred tax assets:
Allowance for loan losses	84,812	$ 110,248
Deferred Tax Assets, Other Comprehensive Loss	12,404	0
Other accruals not currently deductible	7,165	20,502
Share-based compensation expense	9,418	15,498
State income taxes	9,186	12,682
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation	8,336	6,799
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Deferred Rent	8,169	10,050
Loan fee income	1,189	8,266
Net operating loss	2,300	4,116
Other	3,639	2,168
Deferred tax assets	146,618	190,329
Valuation allowance	(2,624)	(4,440)
Net deferred tax assets after valuation allowance	143,994	185,889
Deferred tax liabilities:
DeferredTaxLiabilities,ChangeInAccountingMethod	(15,953)	(35,262)
Deferred Tax Liabilities, Investments	(11,145)	0
Derivative equity warrant assets	(29,127)	(36,406)
Net unrealized gains on available-for-sale securities	0	(17,970)
Deferred Tax Assets, Property, Plant and Equipment	(9,223)	(11,956)
Nonmarketable securities	(10,724)	(6,075)
Other	(3,977)	(6,380)
Deferred tax liabilities	(80,149)	(114,049)
Net deferred tax (liabilities) assets	$ 63,845	$ 71,840

Income Taxes Changes in Unrecog

Income Taxes Changes in Unrecognized Tax Benefit (Including Interest and Penalties) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 8,900
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	5,711	$ 3,658	$ 3,497
Additions for tax positions for current year	3,141	793	1,208
Additions for tax positions for prior years	4,132	1,593	228
Lapse of the applicable statute of limitations	(77)	(46)	(25)
Reduction for tax positions for prior years	(224)	(287)	(1,250)
Ending Balance	12,683	5,711	3,658
Unrecognized Tax Benefits Before Interest And Penalties
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	5,269	3,357	3,397
Additions for tax positions for current year	3,141	793	1,208
Additions for tax positions for prior years	3,378	1,427	0
Lapse of the applicable statute of limitations	(60)	(37)	(20)
Reduction for tax positions for prior years	(223)	(271)	(1,228)
Ending Balance	11,505	5,269	3,357
Interest & Penalties
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	442	301	100
Additions for tax positions for current year	0	0	0
Additions for tax positions for prior years	754	166	228
Lapse of the applicable statute of limitations	(17)	(9)	(5)
Reduction for tax positions for prior years	(1)	(16)	(22)
Ending Balance	$ 1,178	$ 442	$ 301

Employee Compensation and Be125

Employee Compensation and Benefit Plans Expenses Incurred Under Certain Employee Compensation and Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Benefits Disclosure [Line Items]
Incentive Compensation Plans	$ 125,584	$ 96,892	$ 97,565
Direct Drive Incentive Compensation Plan	18,721	21,174	21,930
Retention Program	1,317	1,475	1,996
Warrant Incentive Plan	15,386	4,954	9,110
Deferred Compensation Arrangement with Individual, Compensation Expense	203	1,318	2,404
SVBFG 401(k) Plan	17,860	16,078	13,809
SVBFG Employee Stock Ownership Plan	$ 4,719	$ 3,159	$ 8,585

Employee Compensation and Be126

Employee Compensation and Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Contribution Plan Description of 401 K Plan
Employee Benefits Disclosure [Line Items]
Maximum percentage of pre-tax income employees are allowed to contribute towards 401(k) plan	75.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount	$ 18,000	$ 18,000	$ 18,000
Maximum percentage of employer matching contributions towards 401(k) plan	5.00%
Employee Stock Ownership Plan (ESOP), Plan
Employee Benefits Disclosure [Line Items]
Maximum percentage of employee's eligible pay earned in the fiscal year contributed by the company in cash or common stock towards ESOP	10.00%
ESOP contributions vesting period	5 years
Employee Home Ownership Plan
Employee Benefits Disclosure [Line Items]
Fixed-rate mortgage loan term, minimum	5 years
Fixed-rate mortgage loan term, maximum	7 years
Amortization period	30 years
Maximum loan amount percentage lesser of purchase price or the appraised value	80.00%
Mortgage loans rate	2.00%
Deferred Compensation Plan
Employee Benefits Disclosure [Line Items]
Maximum percentage of base salary that may be deferred under the DC Plan	50.00%
Maximum percentage of eligible bonus payment that may be deferred under the DC Plan	100.00%
Maximum deferral term under the DC Plan	12 months
Deferrals under the DC Plan	$ 5,500,000	4,400,000	3,700,000
DC Plan investment gains	$ 4,700,000	$ 2,400,000	$ 100,000

Off-Balance Sheet Arrangemen127

Off-Balance Sheet Arrangements, Guarantees and Other Commitments Minimum Future Payments Under Noncancelable Operating Leases (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Disclosure Minimum Future Payments Under Noncancelable Operating Leases [Abstract]
2,017	$ 35,627
2,018	35,545
2,019	32,117
2,020	31,451
2,021	27,501
2022 and thereafter	64,234
Net minimum operating lease payments	$ 226,475

Off-Balance Sheet Arrangemen128

Off-Balance Sheet Arrangements, Guarantees and Other Commitments Summary Information Related to Commitments to Extend Credit (Excluding Letters of Credit) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure Summary Information Related To Commitments To Extend Credit [Abstract]
Fixed interest rate commitments	$ 1,478,157	$ 1,475,179
Variable interest rate commitments	14,034,169	13,572,161
Total loan commitments available for funding	15,512,326	15,047,340
Commercial and standby letters of credit	1,950,211	1,695,856
Total unfunded credit commitments	17,462,537	16,743,196
Commitments unavailable for funding	2,117,057	1,719,524
Reserve For Unfunded Credit Commitments	$ 51,770	$ 45,265	$ 34,415	$ 36,419

Off-Balance Sheet Arrangemen129

Off-Balance Sheet Arrangements, Guarantees and Other Commitments Summary of Commercial and Standby Letters of Credit (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Guarantor Obligations [Line Items]
Expires In One Year or Less	$ 1,878,287
Expires After One Year	71,924
Total Amount Outstanding	1,950,211	$ 1,695,856
Maximum Amount of Future Payments	1,950,211
Financial standby letters of credit
Guarantor Obligations [Line Items]
Expires In One Year or Less	1,765,857
Expires After One Year	60,819
Total Amount Outstanding	1,826,676
Maximum Amount of Future Payments	1,826,676
Performance standby letters of credit
Guarantor Obligations [Line Items]
Expires In One Year or Less	94,519
Expires After One Year	11,105
Total Amount Outstanding	105,624
Maximum Amount of Future Payments	105,624
Commercial letters of credit
Guarantor Obligations [Line Items]
Expires In One Year or Less	17,911
Expires After One Year	0
Total Amount Outstanding	17,911
Maximum Amount of Future Payments	$ 17,911

Off-Balance Sheet Arrangemen130

Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2016
Commitments and Contingencies Disclosure [Line Items]
Rent expense for premises and equipment leased under operating leases	$ 24.8	$ 31.3	$ 21.9
Standby Letter of Credit
Commitments and Contingencies Disclosure [Line Items]
Deferred Revenue		12		$ 10
Collateral in the form of cash		$ 961

Total Capital Commitments, Unfu

Total Capital Commitments, Unfunded Capital Commitments, and Our Ownership in Each Fund (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Venture Capital and Private Equity Fund Investments [Line Items]
Unfunded Commitments	$ 5,842
Strategic Investors Fund, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Unfunded Commitments	1,338
Capital Preferred Return Fund, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Unfunded Commitments	1,952
Growth Partners, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Unfunded Commitments	2,552
Parent Company
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	464,655
Unfunded Commitments	16,142
Parent Company | CP I, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	6,000
Unfunded Commitments	$ 270
Ownership percentage of each Fund	10.70%
Parent Company | CP II, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 1,200
Unfunded Commitments	$ 162
Ownership percentage of each Fund	5.10%
Parent Company | Shanghai Yangpu Venture Capital Fund (LP)
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 891
Unfunded Commitments	$ 0
Ownership percentage of each Fund	6.80%
Parent Company | Strategic Investors Fund, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 15,300
Unfunded Commitments	$ 688
Ownership percentage of each Fund	12.60%
Parent Company | Strategic Investors Fund II, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 15,000
Unfunded Commitments	$ 1,050
Ownership percentage of each Fund	8.60%
Parent Company | Strategic Investors Fund III, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 15,000
Unfunded Commitments	$ 1,275
Ownership percentage of each Fund	5.90%
Parent Company | Strategic Investors Fund IV, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 12,239
Unfunded Commitments	$ 2,325
Ownership percentage of each Fund	5.00%
Parent Company | Strategic Investors Fund V Funds
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 515
Unfunded Commitments	131
Parent Company | Capital Preferred Return Fund, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	12,688
Unfunded Commitments	$ 0
Ownership percentage of each Fund	20.00%
Parent Company | Growth Partners, L.P.
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 24,670
Unfunded Commitments	$ 1,340
Ownership percentage of each Fund	33.00%
Parent Company | Debt Funds (Equity Method Accounting)
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	$ 58,493
Unfunded Commitments	0
Parent Company | Other Fund Investments
Venture Capital and Private Equity Fund Investments [Line Items]
Capital Commitments	302,659
Unfunded Commitments	$ 8,901

Total Capital Commitments, U132

Total Capital Commitments, Unfunded Capital Commitments, and Our Ownership in Each Fund (Footnote Information) (Detail) - Venture capital and private equity fund investments - Investment	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
CP II, L.P. | Fair value accounting | Direct ownership interest
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	1.30%
CP II, L.P. | Fair value accounting | Indirect ownership interest
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	3.80%
Other private equity fund | Fair value accounting
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	0.00%	58.20%
Other Fund Investments
Venture Capital and Private Equity Fund Investments [Line Items]
Number of other funds with investment commitments	241
Upper Limit | Other Fund Investments
Venture Capital and Private Equity Fund Investments [Line Items]
Company Direct and Indirect Ownership in Limited Partnership	5.00%

Remaining Unfunded Commitments

Remaining Unfunded Commitments to Venture Capital or Private Equity Funds by our Consolidated Managed Funds (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Line Items]
Unfunded Commitments	$ 5,842
Strategic Investors Fund, L.P.
Commitments and Contingencies Disclosure [Line Items]
Unfunded Commitments	1,338
Capital Preferred Return Fund, L.P.
Commitments and Contingencies Disclosure [Line Items]
Unfunded Commitments	1,952
Growth Partners, L.P.
Commitments and Contingencies Disclosure [Line Items]
Unfunded Commitments	$ 2,552
Venture capital and private equity fund investments
Commitments and Contingencies Disclosure [Line Items]
Commitments Expiration Period	10 years
Fund Commitments, Call Unrestricted, Percentage of Committed Capital	100.00%
Lower Limit | Venture capital and private equity fund investments
Commitments and Contingencies Disclosure [Line Items]
Expected commitment period to invest in venture capital and private equity funds (in years)	5 years
Upper Limit | Venture capital and private equity fund investments
Commitments and Contingencies Disclosure [Line Items]
Expected commitment period to invest in venture capital and private equity funds (in years)	7 years

Fair Value of Financial Inst134

Fair Value of Financial Instruments Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	$ 11,120,664	$ 12,620,411
Fair value	108,389	78,947
Fair value	108,581	64,438
Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	810
Client interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	11,753	10,110
Fair value	11,940	9,770
Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	414	3,057
Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	5,201	968
U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	6,840,502	8,909,491
U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	1,567,128	2,078,375
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	72,269	5,597
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	11,120,664	12,620,411
Total assets	11,481,237	12,974,923
Total liabilities	108,581	64,438
Fair Value, Measurements, Recurring | Derivatives designated as hedging instruments | Interest rate swaps | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		810
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	96,636	68,027
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	96,641	54,668
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Equity warrant assets | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	123,763	131,123
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	11,753	10,110
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		9,770
Fair Value, Measurements, Recurring | Derivatives not designated as hedging instruments | Other derivative instruments | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	11,940
Fair Value, Measurements, Recurring | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	128,421	144,442
Fair Value, Measurements, Recurring | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	6,840,502	8,909,491
Fair Value, Measurements, Recurring | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	1,567,128	2,078,375
Fair Value, Measurements, Recurring | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	2,267,035	1,152,665
Fair Value, Measurements, Recurring | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	373,730	474,283
Fair Value, Measurements, Recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	72,269	5,597
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	6,840,660	8,909,666
Total assets	6,840,970	8,910,419
Total liabilities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives designated as hedging instruments | Interest rate swaps | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives not designated as hedging instruments | Equity warrant assets | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives not designated as hedging instruments | Other derivative instruments | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	310	753
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	6,840,502	8,909,491
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	158	175
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	4,280,004	3,710,745
Total assets	4,390,825	3,792,002
Total liabilities	108,581	64,438
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives designated as hedging instruments | Interest rate swaps | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		810
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	96,636	68,027
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	96,641	54,668
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Equity warrant assets | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	2,432	2,310
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	11,753	10,110
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		9,770
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Derivatives not designated as hedging instruments | Other derivative instruments | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	11,940
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	1,567,128	2,078,375
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	2,267,035	1,152,665
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	373,730	474,283
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	72,111	5,422
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Total assets	122,250	130,853
Total liabilities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Derivatives designated as hedging instruments | Interest rate swaps | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Derivatives not designated as hedging instruments | Foreign Exchange Contract [Member] | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Derivatives not designated as hedging instruments | Equity warrant assets | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	121,331	128,813
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Derivatives not designated as hedging instruments | Client interest rate derivatives | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Derivatives not designated as hedging instruments | Other derivative instruments | Other liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	919	2,040
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations | Variable rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Other securities | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	310	753
Other securities | Fair Value, Measurements, Recurring | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	310	753
Other securities | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	310	753
Other securities | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0
Other securities | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0
Other venture capital investments | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	919	2,040
Other venture capital investments | Fair Value, Measurements, Recurring | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	919	2,040
Other venture capital investments | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0
Other venture capital investments | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0
Other venture capital investments | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	919	2,040
Venture capital and private equity fund investments | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	127,192	141,649
Venture capital and private equity fund investments | Fair Value, Measurements, Recurring | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	127,192	141,649
Venture capital and private equity fund investments | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0
Venture capital and private equity fund investments | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0
Venture capital and private equity fund investments | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	$ 0	$ 0

Fair Value of Financial Inst135

Fair Value of Financial Instruments Assets and Liabilities Measured at Fair Value on a Recurring Basis (Footnote Information) (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 11,481,237	$ 12,974,923
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	6,840,970	8,910,419
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	122,250	130,853
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	4,390,825	3,792,002
Noncontrolling Interests | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	200	600
Noncontrolling Interests | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 800	$ 1,800

Fair Value of Financial Inst136

Fair Value of Financial Instruments Additional Information about Level 3 Assets Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity warrant assets | Other Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 128,813	$ 135,168
Total Realized and Unrealized Gains (Losses) Included in Income	54,263	38,091
Sales	(74,769)	(56,643)
Issuances	14,537	13,405
Distributions and Other Settlements	0	0
Transfers Out of Level 3	(1,513)	(1,208)
Ending Balance		128,813	$ 135,168
Non-marketable securities | Fair value accounting | Other venture capital investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	2,040	2,040
Total Realized and Unrealized Gains (Losses) Included in Income	971	(21)
Sales	(2,092)	(4)
Issuances	0	0
Distributions and Other Settlements	0	25
Transfers Out of Level 3	0	0
Ending Balance		2,040	2,040
Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	130,853	137,208	117,989
Total Realized and Unrealized Gains (Losses) Included in Income	55,234	38,070	72,594
Sales	(76,861)	(56,647)	(63,400)
Issuances	14,537	13,405	12,534
Distributions and Other Settlements	0	25	(87)
Transfers Out of Level 3	(1,513)	(1,208)	(2,422)
Ending Balance	122,250	130,853	137,208
Fair Value, Measurements, Recurring | Equity warrant assets | Other Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	128,813	135,168	114,698
Total Realized and Unrealized Gains (Losses) Included in Income			71,402
Sales			(61,044)
Issuances			12,534
Distributions and Other Settlements			0
Transfers Out of Level 3			(2,422)
Ending Balance	121,331	128,813	135,168
Fair Value, Measurements, Recurring | Non-marketable securities | Fair value accounting | Other venture capital investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	2,040	2,040	3,291
Total Realized and Unrealized Gains (Losses) Included in Income			1,192
Sales			(2,356)
Issuances			0
Distributions and Other Settlements			(87)
Transfers Out of Level 3			0
Ending Balance	$ 919	$ 2,040	$ 2,040

Fair Value of Financial Inst137

Fair Value of Financial Instruments Unrealized Gains Included in Earnings Attributable to Level 3 Assets Held (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Unrealized Gains (Losses) [Line Items]
Unrealized gains included in earnings attributable to Level 3 assets still held	$ 10,730	$ 16,241
Unrealized gains (losses) attributable to noncontrolling interests	(397)	1,553
Equity warrant assets | Other Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Unrealized Gains (Losses) [Line Items]
Unrealized gains included in earnings attributable to Level 3 assets still held	11,174	14,502
Non-marketable securities | Fair value accounting | Other venture capital investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Unrealized Gains (Losses) [Line Items]
Unrealized gains included in earnings attributable to Level 3 assets still held	$ (444)	$ 1,739

Fair Value of Financial Inst138

Fair Value of Financial Instruments Quantitative Information About Significant Unobservable Inputs (Detail) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Equity Warrant Asset, Private Portfolio | Other Assets
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 119,395	$ 128,049
Valuation Technique	Black-Scholes option pricing model	Black-Scholes option pricing model
Volatility	36.70%	36.90%
Risk-Free interest rate	1.80%	1.30%
Marketability discount	16.40%	17.10%
Remaining Life Assumption	45.00%	45.00%
Equity Warrant Asset, Public Portfolio | Other Assets
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 1,936	$ 764
Valuation Technique	Black-Scholes option pricing model	Black-Scholes option pricing model
Sales Restrictions Discount	15.50%	17.70%
Volatility	47.90%	46.60%
Risk-Free interest rate	2.10%	2.10%
Other venture capital investments | Fair value accounting
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 919	$ 2,040
Valuation Technique	Private company equity pricing	Private company equity pricing

Fair Value of Financial Inst139

Fair Value of Financial Instruments Quantitative Information About Significant Unobservable Inputs (Footnote Information) (Detail)	12 Months Ended
	Dec. 31, 2017
Equity Warrant Asset, Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Weighted average contractual remaining term	5 years 9 months 85 days
Estimated remaining life	2 years 7 months 30 days
Lower Limit
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Marketability discount	10.00%
Duration of the sale restrictions	3 months
Upper Limit
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Marketability discount	20.00%
Duration of the sale restrictions	6 months

Fair Value of Financial Inst140

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
6.05% Subordinated Notes
Debt Disclosure [Line Items]
Stated interest rate	6.05%	6.05%
5.375% Senior Notes
Debt Disclosure [Line Items]
Stated interest rate	5.375%	5.375%
7.0% Junior Subordinated Debentures
Debt Disclosure [Line Items]
Stated interest rate	7.00%	7.00%
Fair Value, Measurements, Recurring
Debt Disclosure [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	$ (1,513)	$ (1,208)	$ (2,422)

Fair Value of Financial Inst141

Fair Value of Financial Instruments Summary of Estimated Fair Values of Financial Instruments not Carried at Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	$ 12,548,280	$ 8,376,138
Net loans	22,851,292	19,674,578
Short-term borrowings	1,033,730	512,668
Time Deposits	47,146	56,118
Federal Funds Purchased
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	330,000	0
Federal Home Loan Bank Advances
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Federal Home Loan Bank Advances	700,000	500,000
Other short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	3,730	12,668
3.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	347,303	346,979
5.375% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	348,189	347,586
6.05% Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Subordinated Notes	0	46,646
7.0% Junior Subordinated Debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Junior Subordinated Debentures	0	54,493
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	2,923,075	2,545,750
Held-to-maturity Securities, Fair Value	12,663,455	8,426,998
Non-marketable securities (cost and equity method accounting)	120,019	120,037
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Non-Marketable Securities	228,399	245,626
FHLB and FRB stock	60,020	57,592
Accrued interest receivable	141,773	111,222
Non-maturity deposits (2)	44,206,929	38,923,750
Time Deposits	47,146	56,118
Accrued interest payable	11,192	12,013
Commitments to extend credit	0	0
Carrying Amount | Federal Funds Purchased
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	330,000
Carrying Amount | Federal Home Loan Bank Advances
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Federal Home Loan Bank Advances	700,000	500,000
Carrying Amount | Other short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	3,730	12,668
Carrying Amount | 3.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	347,303	346,979
Carrying Amount | 5.375% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	348,189	347,586
Carrying Amount | 6.05% Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Subordinated Notes		46,646
Carrying Amount | 7.0% Junior Subordinated Debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Junior Subordinated Debentures		54,493
Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	2,923,075	2,545,750
Held-to-maturity Securities, Fair Value	12,548,280	8,376,138
Non-marketable securities (cost and equity method accounting)	126,345	127,343
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Non-Marketable Securities	331,496	353,870
FHLB and FRB stock	60,020	57,592
Accrued interest receivable	141,773	111,222
Federal Home Loan Bank Advances	700,000	500,000
Non-maturity deposits (2)	44,206,929	38,923,750
Time Deposits	46,885	55,949
Accrued interest payable	11,192	12,013
Commitments to extend credit	22,208	22,074
Estimated Fair Value | Federal Funds Purchased
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	330,000
Estimated Fair Value | Other short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	3,730	12,668
Estimated Fair Value | 3.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	352,058	337,600
Estimated Fair Value | 5.375% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	374,483	378,777
Estimated Fair Value | 6.05% Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Subordinated Notes		47,489
Estimated Fair Value | 7.0% Junior Subordinated Debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Junior Subordinated Debentures		53,140
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	2,923,075	2,545,750
Held-to-maturity Securities, Fair Value	0	0
Non-marketable securities (cost and equity method accounting)	0	0
FHLB and FRB stock	0	0
Accrued interest receivable	0	0
Non-maturity deposits (2)	44,206,929	38,923,750
Time Deposits	0	0
Accrued interest payable	0	0
Commitments to extend credit	0	0
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) | Federal Funds Purchased
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	330,000
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) | Federal Home Loan Bank Advances
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Federal Home Loan Bank Advances	700,000	500,000
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	3,730	12,668
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) | 5.375% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	0	0
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) | 6.05% Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Subordinated Notes		0
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) | 7.0% Junior Subordinated Debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Junior Subordinated Debentures		0
Estimated Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Held-to-maturity Securities, Fair Value	12,548,280	8,376,138
Non-marketable securities (cost and equity method accounting)	0	0
FHLB and FRB stock	0	0
Accrued interest receivable	141,773	111,222
Non-maturity deposits (2)	0	0
Time Deposits	46,885	55,949
Accrued interest payable	11,192	12,013
Commitments to extend credit	0	0
Estimated Fair Value | Significant Other Observable Inputs (Level 2) | Other short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	0	0
Estimated Fair Value | Significant Other Observable Inputs (Level 2) | 3.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	352,058	337,600
Estimated Fair Value | Significant Other Observable Inputs (Level 2) | 5.375% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	374,483	378,777
Estimated Fair Value | Significant Other Observable Inputs (Level 2) | 6.05% Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Subordinated Notes		47,489
Estimated Fair Value | Significant Other Observable Inputs (Level 2) | 7.0% Junior Subordinated Debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Junior Subordinated Debentures		53,140
Estimated Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Held-to-maturity Securities, Fair Value	0	0
Non-marketable securities (cost and equity method accounting)	126,345	127,343
FHLB and FRB stock	60,020	57,592
Accrued interest receivable	0	0
Non-maturity deposits (2)	0	0
Time Deposits	0	0
Accrued interest payable	0	0
Commitments to extend credit	22,208	22,074
Estimated Fair Value | Significant Unobservable Inputs (Level 3) | Other short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	0	0
Estimated Fair Value | Significant Unobservable Inputs (Level 3) | 5.375% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	0	0
Estimated Fair Value | Significant Unobservable Inputs (Level 3) | 6.05% Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Subordinated Notes		0
Estimated Fair Value | Significant Unobservable Inputs (Level 3) | 7.0% Junior Subordinated Debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Junior Subordinated Debentures		0
Commercial loans | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	20,238,247	17,518,430
Commercial loans | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	20,520,623	17,811,356
Commercial loans | Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	0	0
Commercial loans | Estimated Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	0	0
Commercial loans | Estimated Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	20,520,623	17,811,356
Consumer loans | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	2,613,045	2,156,148
Consumer loans | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	2,593,538	2,199,501
Consumer loans | Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	0	0
Consumer loans | Estimated Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	0	0
Consumer loans | Estimated Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	$ 2,593,538	$ 2,199,501

Fair Value of Financial Inst142

Fair Value of Financial Instruments Summary of Estimated Fair Values of Financial Instruments not Carried at Fair Value (Footnote Information) (Detail) $ in Millions	Dec. 31, 2016USD ($)
6.05% Subordinated Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of the interest rate swap associated with the notes	$ 0.8

Fair Value of Financial Inst143

Fair Value of Financial Instruments Summary of Estimated Fair Values of Investments and Remaining Unfunded Commitments for Each Major Category of Investments (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Carrying Amount	$ 355,591
Fair Value	458,688
Unfunded Commitments	19,686
Non-marketable securities | Fair value accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Carrying Amount	127,192
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	127,192
Unfunded Commitments	5,842
Non-marketable securities | Equity method accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Carrying Amount	89,809
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	89,809
Unfunded Commitments	4,943
Non-marketable securities | Equity method accounting | Debt Securities
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Carrying Amount	21,183
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	21,183
Unfunded Commitments	0
Non-marketable securities | Equity method accounting | Other investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Carrying Amount	18,859
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	18,859
Unfunded Commitments	886
Non-marketable securities | Cost method accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Carrying Amount	98,548
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	201,645
Unfunded Commitments	$ 8,015

Fair Value of Financial Inst144

Fair Value of Financial Instruments Summary of Estimated Fair Values of Investments and Remaining Unfunded Commitments for Each Major Category of Investments (Textual) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 19,686
Non-marketable securities | Fair value accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	127,192
Unfunded Commitments	5,842
Non-marketable securities | Equity method accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	89,809
Unfunded Commitments	4,943
Non-marketable securities | Equity method accounting | Other investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	18,859
Unfunded Commitments	886
Non-marketable securities | Cost method accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	201,645
Unfunded Commitments	8,015
Non-marketable securities | Noncontrolling Interests | Fair value accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Planned Sale, Investments Not Identified, Value	94,200
Unfunded Commitments	$ 4,400
Non-marketable securities | Lower Limit | Fair value accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	10 years
Non-marketable securities | Lower Limit | Equity method accounting | Other investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	10 years
Non-marketable securities | Upper Limit | Fair value accounting | Venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	13 years
Non-marketable securities | Upper Limit | Equity method accounting | Other investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	13 years

Regulatory Matters Capital Rati

Regulatory Matters Capital Ratios for Company and Bank under Federal Regulatory Guidelines, Compared to Minimum Regulatory Capital Requirements for Adequately Capitalized and Well Capitalized Depository Institution (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
SVB Financial Group
CET 1 risk-based capital, actual ratio	12.78%	12.80%
CET 1 risk-based capital, well capitalized minimum ratio	6.50%	6.50%
CET 1 risk-based capital, adequately capitalized minimum ratio	4.50%	4.50%
CET 1 risk-based capital, actual amount	$ 4,182,315,000	$ 3,616,404,000
CET 1 risk-based capital, well capitalized minimum amount	2,127,902,000	1,836,169,000
CET 1 risk-based capital, adequately capitalized minimum amount	$ 1,473,163,000	$ 1,271,194,000
Tier 1 risk-based capital, actual ratio	12.97%	13.26%
Tier 1 risk-based capital, well capitalized minimum ratio	8.00%	8.00%
Tier 1 risk-based capital, adequately capitalized minimum ratio	6.00%	6.00%
Tier 1 risk-based capital, actual amount	$ 4,246,606,000	$ 3,744,605,000
Tier 1 risk-based capital, well capitalized minimum amount	2,618,957,000	2,259,900,000
Tier 1 risk-based capital, adequately capitalized minimum amount	$ 1,964,218,000	$ 1,694,925,000
Total risk-based capital, actual ratio	13.96%	14.21%
Total risk-based capital, well capitalized minimum ratio	10.00%	10.00%
Total risk-based capital, adequately capitalized minimum ratio	8.00%	8.00%
Total risk-based capital, actual amount	$ 4,571,542,000	$ 4,015,236,000
Total risk-based capital, well capitalized minimum amount	3,273,696,000	2,824,875,000
Total risk-based capital, adequately capitalized minimum amount	$ 2,618,957,000	$ 2,259,900,000
Tier 1 leverage, actual ratio	8.34%	8.34%
Tier 1 leverage, adequately capitalized minimum ratio	4.00%	4.00%
Tier 1 leverage, actual amount	$ 4,246,606,000	$ 3,744,605,000
Tier 1 leverage, adequately capitalized minimum amount	$ 2,036,138,000	$ 1,796,387,000
Silicon Valley Bank
CET 1 risk-based capital, actual ratio	12.06%	12.65%
CET 1 risk-based capital, well capitalized minimum ratio	6.50%	650.00%
CET 1 risk-based capital, adequately capitalized minimum ratio	4.50%	450.00%
CET 1 risk-based capital, actual amount	$ 3,787,988,000	$ 3,397,232,000
CET 1 risk-based capital, well capitalized minimum amount	2,041,227,000	1,745,695,000
CET 1 risk-based capital, adequately capitalized minimum amount	$ 1,413,157,000	$ 1,208,558,000
Tier 1 risk-based capital, actual ratio	12.06%	12.65%
Tier 1 risk-based capital, well capitalized minimum ratio	8.00%	8.00%
Tier 1 risk-based capital, adequately capitalized minimum ratio	6.00%	6.00%
Tier 1 risk-based capital, actual amount	$ 3,787,988,000	$ 3,397,232,000
Tier 1 risk-based capital, well capitalized minimum amount	2,512,279,000	2,148,548,000
Tier 1 risk-based capital, adequately capitalized minimum amount	$ 1,884,209,000	$ 1,611,411,000
Total risk-based capital, actual ratio	13.04%	13.66%
Total risk-based capital, well capitalized minimum ratio	10.00%	10.00%
Total risk-based capital, adequately capitalized minimum ratio	8.00%	8.00%
Total risk-based capital, actual amount	$ 4,094,782,000	$ 3,667,709,000
Total risk-based capital, well capitalized minimum amount	3,140,349,000	2,685,685,000
Total risk-based capital, adequately capitalized minimum amount	$ 2,512,279,000	$ 2,148,548,000
Tier 1 leverage, actual ratio	7.56%	7.67%
Tier 1 leverage, well capitalized minimum ratio	5.00%	5.00%
Tier 1 leverage, adequately capitalized minimum ratio	4.00%	4.00%
Tier 1 leverage, actual amount	$ 3,787,988,000	$ 3,397,232,000
Tier 1 leverage, well capitalized minimum amount	2,504,636,000	2,214,467,000
Tier 1 leverage, adequately capitalized minimum amount	$ 2,003,709,000	$ 1,771,574,000

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Reporting Segment Infor

Segment Reporting Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Segment Reporting Information [Line Items]
Net interest income	$ 393,706	$ 373,974	$ 342,696	$ 309,993	$ 296,605	$ 289,161	$ 283,336	$ 281,421	$ 1,420,369	$ 1,150,523		$ 1,006,425
Provision for Loan and Lease Losses	22,242	23,522	15,806	30,734	16,454	20,004	36,746	33,475	92,304	106,679	[1]	95,683	[1]
Noninterest Income	152,266	158,778	128,528	117,659	113,502	144,140	112,776	86,134	557,231	456,552		472,794
Noninterest expense	$ (264,015)	$ (257,761)	$ (251,246)	$ (237,633)	$ (235,186)	$ (220,773)	$ (199,939)	$ (203,899)	(1,010,655)	(859,797)	[1]	(779,962)	[1]
Income before income tax expense									874,641	640,599		603,574
Total average loans, net of unearned income									21,159,394	18,283,591		14,762,941
Total average assets									48,380,272	43,987,451		40,846,377
Total average deposits									42,745,148	38,759,059		36,293,362
Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income									1,274,366	1,040,712		853,882
Provision for Loan and Lease Losses									81,553	93,885		94,913
Noninterest Income									366,000	320,421		272,862
Noninterest expense									(706,341)	(632,264)		(578,888)
Income before income tax expense									852,472	634,984		452,943
Total average loans, net of unearned income									18,479,793	16,047,545		12,984,646
Total average assets									46,303,582	41,494,321		38,438,858
Total average deposits									41,043,731	37,301,483		34,996,194
SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income									58,131	53,582		44,412
Provision for Loan and Lease Losses									4,386	1,812		2,716
Noninterest Income									2,175	2,713		2,011
Noninterest expense									(17,693)	(12,379)		(12,185)
Income before income tax expense									38,227	42,104		31,522
Total average loans, net of unearned income									2,423,078	2,025,381		1,592,065
Total average assets									2,449,763	2,047,513		1,457,461
Total average deposits									1,303,542	1,133,425		1,108,411
SVB Capital
Segment Reporting Information [Line Items]
Net interest income									48	(49)		3
Provision for Loan and Lease Losses									0	0		0
Noninterest Income									58,992	49,365		70,857
Noninterest expense									(19,340)	(15,546)		(14,699)
Income before income tax expense									39,700	33,770		56,161
Total average loans, net of unearned income									0	0		0
Total average assets									325,939	338,848		337,884
Total average deposits									0	0		0
Other Items
Segment Reporting Information [Line Items]
Net interest income									87,824	56,278		108,128
Provision for Loan and Lease Losses									6,365	10,982		(1,946)
Noninterest Income									130,064	84,053		127,064
Noninterest expense									(267,281)	(199,608)		(174,190)
Income before income tax expense									(55,758)	(70,259)		62,948
Total average loans, net of unearned income									256,523	210,665		186,230
Total average assets									(699,012)	106,769		612,174
Total average deposits									$ 397,875	$ 324,151		$ 188,757
[1]	Our consolidated statements of income for the years ended December 31, 2016 and 2015 were modified from prior periods’ presentation to conform to the current period's presentation, which reflects our provision for loan losses and provision for unfunded credit commitments together as our “provision for credit losses”. In prior periods, our provision for unfunded credit commitments were reported separately as a component of noninterest expense.

Segment Information (Additional

Segment Information (Additional Information) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Global Commercial Bank
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 24.9	$ 24.8	$ 20.3

Parent Company Only Condense149

Parent Company Only Condensed Financial Information Condensed Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets:
Cash and cash equivalents	$ 2,923,075	$ 2,545,750	$ 1,503,257	$ 1,811,014	[1]
Investment securities	24,435,172	21,669,961
Net loans	22,851,292	19,674,578
Other assets	876,246	672,688
Total assets	51,214,467	44,683,660
Liabilities and total equity
Other liabilities	911,755	618,383
Total liabilities	46,895,052	40,906,623
SVBFG stockholders' equity	4,179,795	3,642,554
Total liabilities and total equity	51,214,467	44,683,660
Parent Company
Assets:
Cash and cash equivalents	457,324	500,014	$ 377,013	$ 314,236
Investment securities	485,220	244,603
Net loans	0	13,337
Other assets	196,974	197,220
Total assets	4,992,600	4,492,529
Liabilities and total equity
Other liabilities	117,313	100,917
Total liabilities	812,805	849,975
SVBFG stockholders' equity	4,179,795	3,642,554
Total liabilities and total equity	4,992,600	4,492,529
Parent Company | 3.50% Senior Notes
Liabilities and total equity
Notes payable	347,303	346,979
Parent Company | 5.375% Senior Notes
Liabilities and total equity
Notes payable	348,189	347,586
Parent Company | 7.0% Junior Subordinated Debentures
Liabilities and total equity
Notes payable	0	54,493
Parent Company | Bank Subsidiaries
Assets:
Investment in subsidiaries	3,762,542	3,423,427
Parent Company | Nonbank Subsidiaries
Assets:
Investment in subsidiaries	$ 90,540	$ 113,928
[1]	Cash and cash equivalents at December 31, 2014 included $15.0 million recognized in assets held-for-sale in conjunction with the SVBIF sale transaction. On April 13, 2015 we received net proceeds of $39.3 million consisting of the sales price of $48.6 million less $9.3 million of cash and cash equivalents held by SVBIF that were sold.

Parent Company Only Condense150

Parent Company Only Condensed Financial Information Condensed Statement of Income (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Interest income	$ 405,016	$ 385,271	$ 353,927	$ 320,926	$ 307,333	$ 300,413	$ 293,992	$ 291,658	$ 1,465,140		$ 1,193,396	$ 1,046,765
Interest expense	(11,310)	(11,297)	(11,231)	(10,933)	(10,728)	(11,252)	(10,656)	(10,237)	(44,771)		(42,873)	(40,340)
Gains on derivative instruments, net									54,555		37,892	70,963
Gains on investment securities, net									64,603		51,740	89,445
Fund management fees									21,214		19,195	15,941
Income tax expense	(135,051)	(97,351)	(71,656)	(51,405)	(54,825)	(76,877)	(65,047)	(53,584)	(355,463)	[1]	(250,333)	(228,754)
Net income available to common stockholders	$ 117,210	$ 148,620	$ 123,193	$ 101,483	$ 99,466	$ 111,081	$ 92,964	$ 79,174	490,506	[1]	382,685	343,904
Parent Company
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Interest income									2,077		690	964
Interest expense									(34,932)		(35,316)	(34,169)
Dividend income from subsidiary									90,000		40,000	0
Gains on derivative instruments, net									54,555		37,892	70,963
Gains on investment securities, net									37,132		20,644	39,447
Fund management fees									24,613		21,913	2,286
General and administrative expenses									(63,077)		(55,139)	(54,822)
Income tax expense									10,367		423	(14,448)
Loss before net income of subsidiaries									120,735		31,107	10,221
Net income available to common stockholders									490,506		382,685	343,904
Parent Company | Nonbank Subsidiaries
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Loss before net income of subsidiaries									13,002		11,949	26,819
Equity in undistributed net income of subsidiary									13,002		11,949	26,819
Parent Company | Bank Subsidiaries
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Loss before net income of subsidiaries									446,769		379,629	306,864
Equity in undistributed net income of subsidiary									$ 356,769		$ 339,629	$ 306,864
[1]	Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted, for the year ended December 31, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update ("ASU") 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.

Parent Company Only Condense151

Parent Company Only Condensed Financial Information Condensed Statement of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Net income available to common stockholders	$ 117,210	$ 148,620	$ 123,193	$ 101,483	$ 99,466	$ 111,081	$ 92,964	$ 79,174	$ 490,506	[1]	$ 382,685	$ 343,904
Other comprehensive income (loss), net of tax									(24,902)		8,026	(27,300)
Comprehensive income attributable to SVBFG									465,604		390,711	316,604
Parent Company
Net income available to common stockholders									490,506		382,685	343,904
Foreign currency translation gains (losses)									3,769		3,071	(1,492)
Unrealized holding gains (losses) on securities available for sale									22,285		654	(2,041)
Equity in other comprehensive income (losses) of subsidiaries									(50,956)		4,301	(23,767)
Other comprehensive income (loss), net of tax									(24,902)		8,026	(27,300)
Comprehensive income attributable to SVBFG									$ 465,604		$ 390,711	$ 316,604
[1]	Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted, for the year ended December 31, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update ("ASU") 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.

Parent Company Only Condense152

Parent Company Only Condensed Financial Information Condensed Statements of Cash Flows (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Adjustments to reconcile net income to net cash used for operating activities:
Gains on derivative instruments, net		$ (54,555)	$ (37,892)	$ (70,963)
Gains on investment securities, net		(64,603)	(51,740)	(89,445)
Amortization of share-based compensation		36,900	35,494	32,239
Other, net		15,882	41,684	64,044
Net cash used for operating activities		580,099	437,977	339,197
Cash flows from investing activities:
Net (increase) decrease in loans		(3,170,099)	(3,157,281)	(2,328,944)
Net cash used for investing activities		(5,903,730)	1,015,344	(6,495,736)
Cash flows from financing activities:
Repayments of Other Long-term Debt		97,781	0	0
Proceeds from issuance of common stock, ESPP, and ESOP		27,003	26,147	22,410
Tax benefit from stock exercises	[1]	0	(3,640)	16,602
Net cash provided by financing activities		5,700,956	(410,828)	5,848,782
Net increase (decrease) in cash and cash equivalents		377,325	1,042,493	(307,757)
Cash and cash equivalents at beginning of period		2,545,750	1,503,257	1,811,014	[2]
Cash and cash equivalents at end of period		2,923,075	2,545,750	1,503,257
Parent Company
Cash flows from operating activities:
Net income attributable to SVBFG		490,506	382,685	343,904
Adjustments to reconcile net income to net cash used for operating activities:
Gains on derivative instruments, net		(54,555)	(37,892)	(70,963)
Gains on investment securities, net		(37,132)	(20,644)	(39,447)
Net income of subsidiaries		(120,735)	(31,107)	(10,221)
Cash dividends from bank subsidiary		90,000	40,000	0
Amortization of share-based compensation		36,900	35,494	32,239
Decrease (increase) in other assets		12,959	35,699	(30,638)
Increase (decrease) in other liabilities		11,774	15,293	28,985
Other, net		131	2,992	15,956
Net cash used for operating activities		90,812	62,049	(53,647)
Cash flows from investing activities:
Net decrease in investment securities from purchases, sales and maturities		(117,743)	54,737	31,380
Net (increase) decrease in loans		13,337	(3,478)	6,825
Net cash used for investing activities		(108,959)	38,445	(269,019)
Cash flows from financing activities:
Repayments of Other Long-term Debt		51,546	0	0
Proceeds from issuance of common stock, ESPP, and ESOP		27,003	26,147	22,410
Tax benefit from stock exercises		0	(3,640)	16,602
Net proceeds from public equity offering		0	0	346,431
Net cash provided by financing activities		(24,543)	22,507	385,443
Net increase (decrease) in cash and cash equivalents		(42,690)	123,001	62,777
Cash and cash equivalents at beginning of period		500,014	377,013	314,236
Cash and cash equivalents at end of period		457,324	500,014	377,013
Parent Company | Bank Subsidiaries
Adjustments to reconcile net income to net cash used for operating activities:
Net income of subsidiaries		(446,769)	(379,629)	(306,864)
Cash flows from investing activities:
Investment in subsidiaries		(38,927)	(14,738)	(378,286)
Parent Company | Nonbank Subsidiaries
Adjustments to reconcile net income to net cash used for operating activities:
Net income of subsidiaries		(13,002)	(11,949)	(26,819)
Cash flows from investing activities:
Investment in subsidiaries		$ 34,374	$ 1,924	$ 71,062
[1]	In 2017 we adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting on a prospective basis with no change to prior period amounts. See Note 2- "Summary of Significant Accounting Policies" of the "Notes to Consolidated Financial Statements" under Part II, Item 8 of this report for additional details.
[2]	Cash and cash equivalents at December 31, 2014 included $15.0 million recognized in assets held-for-sale in conjunction with the SVBIF sale transaction. On April 13, 2015 we received net proceeds of $39.3 million consisting of the sales price of $48.6 million less $9.3 million of cash and cash equivalents held by SVBIF that were sold.

Unaudited Quarterly Financia153

Unaudited Quarterly Financial Data Supplemental Consolidated Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 405,016	$ 385,271	$ 353,927	$ 320,926	$ 307,333	$ 300,413	$ 293,992	$ 291,658	$ 1,465,140		$ 1,193,396		$ 1,046,765
Interest expense	11,310	11,297	11,231	10,933	10,728	11,252	10,656	10,237	44,771		42,873		40,340
Net interest income	393,706	373,974	342,696	309,993	296,605	289,161	283,336	281,421	1,420,369		1,150,523		1,006,425
Provision for loan losses	22,242	23,522	15,806	30,734	16,454	20,004	36,746	33,475	92,304		106,679	[1]	95,683	[1]
Noninterest Income	152,266	158,778	128,528	117,659	113,502	144,140	112,776	86,134	557,231		456,552		472,794
Noninterest expense	264,015	257,761	251,246	237,633	235,186	220,773	199,939	203,899	1,010,655		859,797	[1]	779,962	[1]
Income before income tax expense	259,715	251,469	204,172	159,285	158,467	192,524	159,427	130,181
Income tax expense	135,051	97,351	71,656	51,405	54,825	76,877	65,047	53,584	355,463	[2]	250,333		228,754
Net income before noncontrolling interests	124,664	154,118	132,516	107,880	103,642	115,647	94,380	76,597	519,178		390,266		374,820
Net income attributable to noncontrolling interests	(7,454)	(5,498)	(9,323)	(6,397)	(4,176)	(4,566)	(1,416)	2,577	(28,672)		(7,581)		(30,916)
Net income available to common stockholders	$ 117,210	$ 148,620	$ 123,193	$ 101,483	$ 99,466	$ 111,081	$ 92,964	$ 79,174	$ 490,506	[2]	$ 382,685		$ 343,904
Earnings per common share—basic, in dollars per share	$ 2.22	$ 2.82	$ 2.34	$ 1.94	$ 1.91	$ 2.13	$ 1.79	$ 1.53	$ 9.33	[2]	$ 7.37		$ 6.70
Earnings per common share—diluted, in dollars per share	$ 2.19	$ 2.79	$ 2.32	$ 1.91	$ 1.89	$ 2.12	$ 1.78	$ 1.52	$ 9.20	[2]	$ 7.31		$ 6.62
[1]	Our consolidated statements of income for the years ended December 31, 2016 and 2015 were modified from prior periods’ presentation to conform to the current period's presentation, which reflects our provision for loan losses and provision for unfunded credit commitments together as our “provision for credit losses”. In prior periods, our provision for unfunded credit commitments were reported separately as a component of noninterest expense.
[2]	Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted, for the year ended December 31, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update ("ASU") 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.