Amdocs Limited (DOX) 20-F 16 Dec 19 2019 FY Annual report (foreign) Financial data

Cover

Cover	12 Months Ended
	Sep. 30, 2019shares
Document Information [Line Items]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	AMDOCS LTD
Entity Central Index Key	0001062579
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	Y7
Entity Address, Address Line One	Hirzel House
Entity Address, Address Line Two	Smith Street
Entity Address, City or Town	St. Peter Port
Entity Address Country	GG
Entity Address, Postal Zip Code	GY1 2NG
Contact Personnel Name	Matthew E. Smith
Contact Personnel Email Address	dox_info@amdocs.com
Document Registration Statement	false
Document Annual Report	true
Document Transition Report	false
Document Shell Company Report	false
Security Exchange Name	NASDAQ
Security 12(b) Title	Ordinary Shares, par value £0.01
Trading Symbol	DOX
Entity Common Stock, Shares Outstanding	134,773,123
Contact Phone [Member]
Document Information [Line Items]
City Area Code	314
Local Phone Number	212-8328
Contact Address [Member]
Document Information [Line Items]
Entity Address, Address Line One	1390 Timberlake Manor Parkway
Entity Address, City or Town	Chesterfield
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63017

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Current assets:
Cash and cash equivalents	$ 471,632	$ 418,783
Short-term interest-bearing investments		100,433
Accounts receivable, net	987,858	971,502
Prepaid expenses and other current assets	216,084	229,999
Total current assets	1,675,574	1,720,717
Property and equipment, net	525,314	496,585
Goodwill	2,462,835	2,444,895
Intangible assets, net	205,162	265,249
Other noncurrent assets	423,941	420,369
Total assets	5,292,826	5,347,815
Current liabilities:
Accounts payable	176,508	194,738
Accrued expenses and other current liabilities	647,657	706,637
Accrued personnel costs	265,583	261,168
Deferred revenue	118,182	132,414
Total current liabilities	1,207,930	1,294,957
Deferred income taxes and taxes payable	207,508	224,572
Other noncurrent liabilities	334,922	336,244
Total liabilities	1,750,360	1,855,773
Amdocs Limited Shareholders' equity:
Preferred Shares - Authorized 25,000 shares; £0.01 par value; 0 shares issued and outstanding
Ordinary Shares - Authorized 700,000 shares; £0.01 par value; 277,148 and 275,896 issued and 134,773 and 140,177 outstanding, in 2019 and 2018, respectively	4,452	4,436
Additional paid-in capital	3,667,662	3,587,625
Treasury stock, at cost - 142,375 and 135,719 ordinary shares in 2019 and 2018, respectively	(5,182,409)	(4,784,352)
Accumulated other comprehensive (loss) income	(2,547)	(32,731)
Retained earnings	5,012,799	4,673,901
Total Amdocs Limited shareholders' equity	3,499,957	3,448,879
Noncontrolling interests	42,509	43,163
Total equity	3,542,466	3,492,042
Total liabilities and equity	$ 5,292,826	$ 5,347,815

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - £ / shares	Sep. 30, 2019	Sep. 30, 2018
Statement of Financial Position [Abstract]
Preferred Shares, authorized	25,000,000	25,000,000
Preferred Shares, par value	£ 0.01	£ 0.01
Preferred Shares, issued	0	0
Preferred Shares, outstanding	0	0
Ordinary Shares, authorized	700,000,000	700,000,000
Ordinary Shares, par value	£ 0.01	£ 0.01
Ordinary Shares, issued	277,148,000	275,896,000
Ordinary Shares, outstanding	134,773,000	140,177,000
Treasury stock, at cost, ordinary shares	142,375,000	135,719,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2017
Income Statement [Abstract]
Revenue	$ 4,086,669		$ 3,974,837		$ 3,867,155
Operating expenses:
Cost of revenue	2,653,172		2,595,276		2,507,656
Research and development	273,936		276,615		259,097
Selling, general and administrative	492,457		481,093		472,778
Amortization of purchased intangible assets and other	97,358		108,489		110,291
Non-recurring charges			85,057
Total operating expenses	3,516,923		3,546,530		3,349,822
Operating income	569,746		428,307		517,333
Interest and other expense, net	1,859		6,766		4,421
Income before income taxes	567,887		421,541		512,912
Income taxes	88,441		67,145		76,086
Net income	$ 479,446	[1]	$ 354,396	[1]	$ 436,826
Basic earnings per share	$ 3.49		$ 2.49		$ 2.99
Diluted earnings per share	$ 3.47		$ 2.47		$ 2.96
[1]	In fiscal years 2019 and 2018, all of the Company's net income is attributable to Amdocs Limited as the net income attributable to the Non-controlling interests is negligible.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income		$ 479,446	[1]	$ 354,396	[1]	$ 436,826
Other comprehensive income (loss), net of tax
Net change in fair value of cash flow hedges	[2]	30,553		(51,116)		11,994
Net change in fair value of available-for-sale securities	[3]	1,592		(1,182)		(978)
Net actuarial (loss) gain on defined benefit plan	[4]	(1,961)		777		1,679
Other comprehensive income (loss), net of tax		30,184		(51,521)		12,695
Comprehensive income		$ 509,630		$ 302,875		$ 449,521
[1]	In fiscal years 2019 and 2018, all of the Company's net income is attributable to Amdocs Limited as the net income attributable to the Non-controlling interests is negligible.
[2]	Net of tax (expense) benefit of $(2,458), $4,482 and $651 for the fiscal years ended September 30, 2019, 2018 and 2017, respectively.
[3]	Net of tax benefit (expense) of $0, $9 and $(4) for the fiscal years ended September 30, 2019, 2018 and 2017, respectively.
[4]	Net of tax benefit (expense) of $1,080, $(254) and $(697) for the fiscal years ended September 30, 2019, 2018 and 2017, respectively.

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Tax (expense) benefit on change in fair value of cash flow hedges	$ (2,458)	$ 4,482	$ 651
Tax benefit (expense) on change in fair value of available-sale-of securities	0	9	(4)
Tax benefit (expense) on unrealized (loss) gain on defined benefit plan	$ 1,080	$ (254)	$ (697)

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands		Total	Ordinary Shares	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive (Loss) Income	[1]	Retained Earnings	Total Amdocs Limited Shareholders' Equity	Non-controlling Interests	[2]
Balance at Sep. 30, 2016		$ 3,453,561	$ 4,377	$ 3,322,789	$ (4,024,527)	$ 6,095		$ 4,144,827	$ 3,453,561
Balance, Shares at Sep. 30, 2016			147,134
Comprehensive income:
Net income		436,826						436,826	436,826
Other comprehensive income (loss), net of tax		12,695				12,695			12,695
Comprehensive income		449,521							449,521
Employee stock options exercised		87,976	$ 28	87,948					87,976
Employee stock options exercised, Shares			2,220
Repurchase of shares		(340,597)			(340,597)				(340,597)
Repurchase of shares, Shares			(5,519)
Tax benefit from equity-based awards		3,611		3,611					3,611
Cash dividends declared		(124,546)						(124,546)	(124,546)
Issuance of restricted stock, net of forfeitures		5	$ 5						5
Issuance of restricted stock, net of forfeitures, Shares			556
Equity-based compensation expense related to employees		44,539		44,539					44,539
Balance at Sep. 30, 2017		3,574,070	$ 4,410	3,458,887	(4,365,124)	18,790		4,457,107	3,574,070
Balance, Shares at Sep. 30, 2017			144,391
Comprehensive income:
Net income	[2]	354,396						354,396	354,396
Other comprehensive income (loss), net of tax		(51,521)				(51,521)			(51,521)
Comprehensive income		302,875							302,875
Employee stock options exercised		81,286	$ 24	81,262					81,286
Employee stock options exercised, Shares			1,800
Repurchase of shares		(419,228)			(419,228)				(419,228)
Repurchase of shares, Shares			(6,337)
Cash dividends declared		(137,602)						(137,602)	(137,602)
Issuance of restricted stock, net of forfeitures		2	$ 2						2
Issuance of restricted stock, net of forfeitures, Shares			323
Equity-based compensation expense related to employees		47,476		47,476					47,476
Changes in Noncontrolling interests		43,163								$ 43,163
Balance at Sep. 30, 2018		$ 3,492,042	$ 4,436	3,587,625	(4,784,352)	(32,731)		4,673,901	3,448,879	43,163
Balance, Shares at Sep. 30, 2018		140,177	140,177
Comprehensive income:
Net income	[2]	$ 479,446						479,446	479,446
Other comprehensive income (loss), net of tax		30,184				30,184			30,184
Comprehensive income		509,630							509,630
Employee stock options exercised		$ 41,498	$ 11	41,487					41,498
Employee stock options exercised, Shares		874	874
Repurchase of shares		$ (398,057)			(398,057)				(398,057)
Repurchase of shares, Shares		(6,656)	(6,656)
Cash dividends declared		$ (150,982)						(150,982)	(150,982)
Issuance of restricted stock, net of forfeitures		5	$ 5						5
Issuance of restricted stock, net of forfeitures, Shares			378
Equity-based compensation expense related to employees		38,550		38,550					38,550
Changes in Noncontrolling interests		(654)								(654)
Balance at Sep. 30, 2019		$ 3,542,466	$ 4,452	$ 3,667,662	$ (5,182,409)	$ (2,547)		5,012,799	3,499,957	$ 42,509
Balance, Shares at Sep. 30, 2019		134,773	134,773
Cumulative effect adjustment	[3]	$ 10,434						$ 10,434	$ 10,434
[1]	As of September 30, 2019, 2018 and 2017, accumulated other comprehensive (loss) income is comprised of unrealized gain (loss) on derivatives, net of tax, of $3,945, $(26,608) and $24,508 , unrealized loss on short-term interest-bearing investments, net of tax, of $0, $(1,592) and $(410) and unrealized loss on defined benefit plan, net of tax, of $(6,492), $(4,531) and $(5,308).
[2]	In fiscal years 2019 and 2018, all of the Company's net income is attributable to Amdocs Limited as the net income attributable to the Non-controlling interests is negligible.
[3]	The Cumulative effect adjustments as of October 1, 2018 include an increase of $14,294 to retained earnings due to the impact of adoptions of ASU No. 2014-09 (ASC 606) and decrease of $3,860 to retained earnings due to adoption of ASU No. 2016-16.

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - USD ($) $ in Thousands	Oct. 01, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Cash dividends declared per ordinary share		$ 1.105	$ 0.970	$ 0.855
Unrealized gain (loss) on derivatives, net of tax		$ 3,945	$ (26,608)	$ 24,508
Unrealized loss on short-term interest-bearing investments, net of tax		0	(1,592)	(410)
Unrealized loss on defined benefit plan, net of tax		$ (6,492)	$ (4,531)	$ (5,308)
Accounting Standards Update 2014-09 [Member]
Increase in retained earnings	$ 14,294
Accounting Standards Update 2016-16 [Member]
Decrease in retained earnings	$ 3,860

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2017
Cash Flow from Operating Activities:
Net income		$ 479,446	[1]	$ 354,396	[1]	$ 436,826
Reconciliation of net income to net cash provided by operating activities:
Depreciation and amortization		205,772		211,224		214,885
Equity-based compensation expense		38,550		47,476		44,539
Deferred income taxes		(13,950)		25,098		6,551
Excess tax benefit from equity-based compensation						(4,666)
Loss from short-term interest-bearing investments		737		1,324		9
Net changes in operating assets and liabilities, net of amounts acquired:
Accounts receivable, net		6,589		(66,451)		(41,075)
Prepaid expenses and other current assets		25,907		(18,736)		11,002
Other noncurrent assets		(1,635)		9,674		(52,667)
Accounts payable, accrued expenses and accrued personnel		(60,042)		25,348		72,049
Deferred revenue		(37,855)		7,650		(50,230)
Income taxes payable, net		6,025		(31,036)		(15,145)
Other noncurrent liabilities		6,833		(8,718)		14,034
Net cash provided by operating activities		656,377		557,249		636,112
Cash Flow from Investing Activities:
Purchase of property and equipment, net	[2]	(128,086)		(231,146)		(133,392)
Proceeds from sale of short-term interest-bearing investments		101,287		303,090		278,066
Purchase of short-term interest-bearing investments				(76,037)		(281,983)
Net cash paid for acquisitions		(60,572)		(355,142)		(18,064)
Other		615		(3,157)		(29,940)
Net cash used in investing activities		(86,756)		(362,392)		(185,313)
Cash Flow from Financing Activities:
Borrowings under financing arrangements				120,000		200,000
Payments under financing arrangements				(120,000)		(400,000)
Repurchase of shares		(398,057)		(419,228)		(340,597)
Proceeds from employee stock option exercises		41,483		81,280		87,586
Payments of dividends		(147,616)		(134,292)		(121,503)
Investment by noncontrolling interests, net	[2]	(4,776)		47,013
Payment of contingent consideration from a business acquisition		(7,470)
Excess tax benefit from equity-based compensation and other		(336)		(458)		4,666
Net cash used in financing activities		(516,772)		(425,685)		(569,848)
Net increase (decrease) in cash and cash equivalents		52,849		(230,828)		(119,049)
Cash and cash equivalents at beginning of year		418,783		649,611		768,660
Cash and cash equivalents at end of year		471,632		418,783		649,611
Cash paid for:
Income taxes, net of refunds		75,790		55,938		67,544
Interest	[3]	$ 7,348		$ 2,009		$ 1,145
[1]	In fiscal years 2019 and 2018, all of the Company's net income is attributable to Amdocs Limited as the net income attributable to the Non-controlling interests is negligible.
[2]	The amounts under "Purchase of property and equipment, net", include proceeds of $9,676 relating to refund of betterment levy for the year ended September 30, 2019 ($4,776 of which was a refund to the noncontrolling interest), proceeds from sale of property and equipment of $151, $459 and $57 for the year ended September 30, 2019, 2018 and 2017, respectively.
[3]	The amounts under "Interest", include payments of interest to financial institution, tax authorities and other.

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Statement of Cash Flows [Abstract]
Proceeds from sale of property and equipment	$ 151	$ 459	$ 57
Proceeds Refund For Property Plant And Equipment	9,676
Proceeds Refund For Non Controlling Interest	$ 4,776

Nature of Entity

Nature of Entity	12 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Entity	Note 1 — Nature of Entity Amdocs Limited (the “Company”) is a leading provider of software and services to communications, cable and satellite, entertainment and media industry service providers of all sizes throughout the world. The Company and its consolidated subsidiaries operate in one segment and design, develop, market, support, implement and operate amdocsONE, an open and modular solution set. The Company is a Guernsey corporation, which directly or indirectly holds numerous subsidiaries around the world, the vast majority of which are wholly-owned. The majority of the Company’s customers are in North America, Europe, Asia-Pacific and the Latin America region. The Company’s main development facilities are located in Brazil, Canada, Cyprus, India, Ireland, Israel, Mexico, the Philippines, the United Kingdom and the United States.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2 — Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles, or GAAP and are denominated in U.S. Dollars. Consolidation The consolidated financial statements include the accounts of the Company and its subsidiaries, the vast majority of which are wholly-owned. All intercompany transactions and balances have been eliminated in consolidation. In December 2017, the Company entered into agreements with Union Investments and Development Limited (“Union”) to partner through a legal entity that is equally owned by the Company and Union for the purpose of acquiring specific land which the Company expects to use as the site for a new campus in Ra’anana, Israel. On January 2, 2018 the Company completed the acquisition of the land. Pursuant to the agreements between the Company and Union, as the Company has control over the construction and ongoing operations of the new campus, the new entity’s financial information is consolidated into the Company’s consolidated financial statements with the portion not owned classified as non-controlling Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the dates of the financial statements, and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Reclassifications From time to time, certain immaterial amounts in prior year financial statements may be reclassified to conform to the current year presentation. Functional Currency The Company manages its foreign subsidiaries as integral direct components of its operations. The operations of the Company’s foreign subsidiaries provide the same type of services with the same type of expenditures throughout the Amdocs group. The Company has determined that its functional currency is the U.S. dollar. The Company periodically assesses the applicability of the U.S. dollar as the Company’s functional currency by reviewing the salient indicators as indicated in the authoritative guidance for foreign currency matters. Cash and Cash Equivalents Cash and cash equivalents consist of cash and interest-bearing investments with insignificant interest rate risk and maturities from acquisition date of 90 days or less. Accounts Receivable Factoring From time to time, the Company uses non-recourse Investments The Company classifies all of its short-term interest-bearing investments as available-for-sale first-in-first-out Property and Equipment Property and equipment are stated at cost. Depreciation is computed using the straight-line method over the estimated useful life of the asset, which primarily ranges from three to ten years. Leasehold improvements are amortized over the shorter of the estimated useful lives or the term of the related lease. Property and equipment that have been fully depreciated and are no longer in use are netted against accumulated depreciation. The Company capitalizes certain expenditures for software that is internally developed for use in the business, which is classified as computer equipment. Amortization of internal use software begins when the software is ready for service and continues on the straight-line method over the estimated useful life. The Company capitalizes the expenditures related to the new campus in Israel, which are classified as building and land. Amortization will begin when the new campus is ready for use and will be amortized on the straight-line basis over the estimated useful life. Goodwill, Intangible Assets and Long-Lived Assets Goodwill and intangible assets deemed to have indefinite lives are subject to an annual impairment test or more frequently if impairment indicators are present. Goodwill impairment is deemed to exist if the net book value of a reporting unit exceeds its estimated fair value. The goodwill impairment test involves a two-step The total purchase price of business acquisitions accounted for using the purchase method is allocated first to identifiable assets and liabilities based on estimated fair values. The excess of the purchase price over the fair value of net assets of purchased businesses is recorded as goodwill. Other definite-life intangible assets consist primarily of core technology and customer relationships. Core technology acquired by the Company is amortized over its estimated useful life on a straight-line basis. Some of the acquired customer relationships are amortized over their estimated useful lives in proportion to the economic benefits realized. This accounting policy generally results in accelerated amortization of such customer relationships as compared to the straight-line method. All other acquired customer relationships are amortized over their estimated useful lives on a straight-line basis. The Company tests long-lived assets, including definite life intangible assets, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability of long-lived assets is based on an estimate of the undiscounted future cash flows resulting from the use of the cash generating unit and its eventual disposition. Measurement of an impairment loss for long-lived assets, including definite life intangible assets that management expects to hold and use is based on the fair value of the cash generating unit. Long-lived assets, including definite life intangible assets, to be disposed of are reported at the lower of carrying amount or fair value less costs to sell. Comprehensive Income Comprehensive income, net of related taxes where applicable, includes, in addition to net income: (i) net change in fair value of available-for-sale (ii) net change in fair value of cash flow hedges; and (iii) net actuarial gains and losses on defined benefit plans. Treasury Stock The Company repurchases its ordinary shares from time to time on the open market or in other transactions and holds such shares as treasury stock. The Company presents the cost to repurchase treasury stock as a reduction of equity. Business Combinations In accordance with business combinations accounting, assets acquired and liabilities assumed, as well as any contingent consideration that may be part of the acquisition agreement, are recorded at their respective fair values at the date of acquisition. For acquisitions that include contingent consideration, the fair value is estimated on the acquisition date as the present value of the expected contingent payments, determined using weighted probabilities of possible payments. The Company remeasures the fair value of the contingent consideration at each reporting period until the contingency is resolved. Except for measurement period adjustments, the changes in fair value are recognized in the consolidated statements of income. Any earn-out In accordance with business combinations accounting, the Company allocates the purchase price of acquired companies to the tangible and intangible assets acquired and liabilities assumed, as well as to in-process Although the Company believes the assumptions and estimates of fair value it has made in the past have been reasonable and appropriate, they are based in part on historical experience and information obtained from the management of the acquired companies and are inherently uncertain and subject to refinement. Critical estimates in valuing certain assets acquired and liabilities assumed include but are not limited to: future expected cash flows from license and service sales, maintenance, customer contracts and acquired developed technologies, expected costs to develop the in-process The Company estimates the fair values of its services, hardware, software license and maintenance obligations assumed. The estimated fair values of these performance obligations are determined utilizing a cost build-up build-up The Company may establish a valuation allowance for certain deferred tax assets and estimate the value of uncertain tax positions of a newly acquired entity. This process requires significant judgment and analysis. Income Taxes The Company records deferred income taxes to reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting and tax purposes. Deferred taxes are computed based on enacted tax rates anticipated to be in effect when the deferred taxes are expected to be paid or realized. A valuation allowance is provided for deferred tax assets if it is more likely than not, the Company will not be able to realize their benefit. Deferred tax liabilities and assets are classified as noncurrent on the balance sheet. Deferred tax liabilities also include anticipated withholding taxes due on subsidiaries’ earnings when paid as dividends to the Company. The Company recognizes the tax benefit from an uncertain tax position only if the weight of available evidence indicates that it is more likely than not that the position will be sustained on audit, including resolution of related appeals or litigation processes, if any. The tax benefits recognized in the financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Interest and penalties related to uncertain tax positions are recognized in the provision for income taxes. See Note 11 to the consolidated financial statements. Revenue Recognition The Company recognizes revenue under the five-step methodology required under ASC 606, which requires the Company to identify the contract with the customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations identified, and recognize revenue when (or as) each performance obligation is satisfied. Revenue is recognized net of any revenue-based taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction and collected by the Company from a customer (for example, sales, use and value added taxes). The Company’s primary revenue categories, related performance obligations, and associated recognition patterns are as follows: Revenue Recognition for projects As a significant portion of the Company’s revenue is satisfied over time as work progresses, the annual and quarterly operating results may be affected by the size and timing of the initiation of customer projects as well as the Company’s progress in completing such projects. Revenue Recognition for subsequent license fee Revenue Recognition for term-based license and perpetual license Revenue Recognition for maintenance Revenue Recognition for ongoing services — Revenue Recognition for managed services arrangement end-to-end The revenue from managed services arrangement is recognized for each individual performance obligation according to its relevant revenue category, including but not limited to, revenue from the management of a customer’s operations, revenue from projects and revenue from ongoing support services. Revenue from the management of a customer’s operations pursuant to managed services arrangements, is recognized over time as services are preformed, using one method of measuring performance such as time elapsed, output produced, volume of data processed or subscriber count that provides the most faithful depiction of the transfer of services, pursuant to the specific contract terms of the managed services arrangement. Typically, managed services arrangements are long term in duration and are not subject to significant seasonality. Revenue Recognition for third-party hardware and software Arrangements with Multiple Performance Obligations Billing terms and conditions generally vary by contract category. Amounts are typically billed as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals (e.g., monthly or quarterly) or upon achievement of contractual milestones. In cases where timing of revenue recognition significantly differs from the timing of invoicing, the Company is considering whether a significant financing component exists. The Company elected to use the practical expedient in assessing the financing component in contracts where the time between cash collection and performance is less than one year. Accounts Receivable — Billed Accounts Receivable — Unbilled — Deferred Revenue — Assets Recognized from the Costs to Obtain a Contract with a Customer — pro-rata In certain circumstances where the Company enters into a contract with a customer for the provision of managed services for a defined period of time, the Company defers certain direct costs incurred at the inception of the contract. These costs include expenses incurred in association with the origination of a contract. In addition, if the revenue for a delivered item is not recognized because it is not separable from the undelivered item, then the Company also defers the cost of the delivered item. The deferred costs are amortized on a straight-line basis over the managed services period, or over the recognition period of the undelivered item. Revenue associated with these capitalized costs is deferred and is recognized over the same period. Cost of Revenue Cost of revenue consists of all costs associated with providing software licenses and services to customers, third party hardware and software including identified losses on contracts. Estimated losses on contracts satisfied over time as work performed are recognized in the period in which the loss is identified. Cost of revenue also includes costs of third-party products associated with selling third-party computer hardware and software products to customers and other third-party services, when the related revenue is recorded at the gross amount. Customers purchasing third-party products and services from the Company generally do so in conjunction with the purchase of the Company’s software and services. Research and Development Research and development expenditures consist of costs incurred in the development of new software modules and product offerings, either as part of the Company’s internal product development programs, which are sold, leased or otherwise marketed. Research and development costs are expensed as incurred. Based on the Company’s product development process, technological feasibility is established upon completion of a detailed program design or, in the absence thereof, completion of a working model. Costs incurred by the Company after achieving technological feasibility and before the product is ready for customer release have been insignificant. Equity-Based Compensation The Company measures and recognizes the compensation expense for all equity-based payments to employees and directors based on their estimated fair values. The Company estimates the fair value of employee stock options at the date of grant using a Black-Scholes valuation model and values restricted stock based on the market value of the underlying shares at the date of grant. The Company recognizes compensation costs using the graded vesting attribution method that results in an accelerated recognition of compensation costs in comparison to the straight-line method. The Company uses a combination of implied volatility of the Company’s traded options and historical stock price volatility (“blended volatility”) as the expected volatility assumption required in the Black-Scholes option valuation model. As equity-based compensation expense recognized in the Company’s consolidated statements of income is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash and cash equivalents, short-term interest-bearing investments, and trade receivables. Cash and cash equivalents are maintained with several financial institutions. Generally, these deposits may be redeemed upon demand and are maintained with financial institutions with reputable credit and therefore bear minimal credit risk. The Company seeks to mitigate its credit risks by spreading such risks across multiple financial institutions and monitoring the risk profiles of these counterparties. The Company has conservative investment policy guidelines under which it invests its excess cash primarily in highly liquid U.S. dollar-denominated securities. The Company’s revenue is generated primarily in North America. To a lesser extent, revenue is generated in Europe and the rest of the world. Most of the Company’s customers are among the largest communications and media companies in the world (or are owned by them). The Company’s business is subject to the effects of general global economic conditions and market conditions in the communications industry. The Company performs ongoing credit analyses of its customer base and generally does not require collateral. The Company evaluates accounts receivable to determine if they ultimately will be collected. Significant judgments and estimates are involved in performing this evaluation, which are based on factors that may affect a customer’s ability to pay, such as past experience, credit quality of the customer, age of the receivable balance and current economic conditions. The allowance for doubtful accounts is for estimated losses resulting from accounts receivable for which their collection is not reasonably probable. The allowance for doubtful accounts as of September 30, 2019 and 2018, was $36,121 and $21,211, respectively. As of September 30, 2019, the Company had one customer with an accounts receivable balance of more than 10% of total accounts receivable, amounting to 16%, which was lower than its respective portion of total revenue. As of September 30, 2018, the Company had one customer with an accounts receivable balance of more than 10% of total accounts receivable, amounting to 19%, which was lower than its respective portion of total revenue. Earnings per Share Basic earnings per share is calculated using the weighted average number of shares outstanding during the period. Diluted earnings per share is computed on the basis of the weighted average number of shares outstanding and the effect of dilutive outstanding equity-based awards using the treasury stock method. The Company includes participating securities (unvested restricted shares that contain non-forfeitable two-class Derivatives and Hedging The Company carries out transactions involving foreign currency exchange derivative financial instruments. The transactions are designed to hedge the Company’s exposure in currencies other than the U.S. dollar. The Company recognizes derivative instruments as either assets or liabilities and measures those instruments at fair value. If a derivative meets the definition of a cash flow hedge and is so designated, changes in the fair value of the derivative are recognized in other comprehensive income (loss) until the hedged item is recognized in earnings. The ineffective portion of a derivative designated as a cash flow hedge is recognized in earnings. If a derivative does not meet the definition of a cash flow hedge, the changes in the fair value are included in earnings. Recent Accounting Standards In November 2018, the Financial Accounting Standards Board, or FASB, issued Accounting Standard Update, or ASU, No. 2018-18 , “Collaborative Arrangements In August 2018, the FASB issued ASU No. 2018-15 , “Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract”. internal-use In August 2018, the FASB issued ASU No. 2018-13 , “Fair Value Measurement”. In August 2018, the FASB issued ASU No. 2018-14, Changes to the Disclosure Requirements for Defined Benefit Plans” In June 2018, the FASB issued ASU No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting ” In August 2017, the FASB issued ASU No. 2017-12, Targeted Improvements to Accounting for Hedging Activities ” In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments ” off-balance In February 2016, the FASB issued ASU No. 2016-02, “Leases”. Adoption of New Accounting Standards In December 2017, the SEC issued Staff Accounting Bulletin No. 118 (“SAB No. 118”) in response to the new tax legislation in the United States (The Tax Cuts and Jobs Act or “The Act”). The Act, which was enacted on December 22, 2017, reduces the US federal corporate tax rate from 35% to 21%, which requires the payment of a one-time one-year one-time In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business In October 2016, the FASB issued ASU No. 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments ” . In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments — Overall ” In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers”. The cumulative impact of adopting ASC 606, which was immaterial, was a net increase in the opening balance of retained earnings as of October 1, 2018, of $14,294, net of tax, from total amount of $4,673,901 to $4,688,195. The impact was primarily related to (i) the removal of the limitation on contingent revenue, as revenue allocated to satisfied performance obligations is no longer restricted to the amount that is not contingent upon the satisfaction of additional performance obligations (ii) the change of definition of contract term to represent the period for which enforceable rights and obligations exist, and (iii) the capitalization and amortization of certain sales commissions in accordance with ASC 606. The following table depicts the impact of adoption as of October 1, 2018, on the Company’s consolidated balance sheet: As of October 1, 2018 Balance as of Adjustments due Balance as of Balance Sheet: Account receivable — unbilled $ 263,997 $ 10,039 $ 274,036 Prepaid expenses and other current assets 229,999 (971 ) 229,028 Other noncurrent assets 420,369 15,636 436,005 Deferred revenue (current) 132,414 14,048 146,462 Accrued expenses and other current liabilities 706,637 (14,062 ) 692,575 Deferred income taxes and taxes payable 224,572 10,424 234,996 Retained Earnings 4,673,901 14,294 4,688,195 The impact of adopting the new standard for the year ended September 30, 2019; was an increase of approximately $26,096 to revenue, most of which was recorded against Account receivable — unbilled and decrease of approximately $11,051 to cost of revenue most of which was recorded against Accrued expenses and other current liabilities.

Acquisitions

Acquisitions	12 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Acquisitions	Note 3 — Acquisitions Entities acquired by the Company during the last three fiscal years have been consolidated into the Company’s results of operations since their respective acquisition dates. These acquisitions, individually and in the aggregate, were not material in any fiscal year. During fiscal year 2019, the Company acquired TTS Wireless for approximately $50,000 in cash and potential additional consideration based on the achievement of certain performance metrics. TTS Wireless is a leading provider of mobile network engineering services, specializing in network optimization, planning and software-enabled solutions. During fiscal year 2018, the Company acquired three technology companies for an aggregate consideration of $355,142 in cash: Vubiquity, a leading provider of premium content services and technology solutions, projekt202, a leader in experience-driven software design and development, and UXP systems (“UXP”) whose User Lifecycle Management solution is a leading platform for empowering digital user relationships and digital identity. See Note 9 to the consolidated financial statement.

Revenue

Revenue	12 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue	Note 4 — Revenue Contract Balances The following table provides information about Accounts receivable, both billed and unbilled and deferred revenue: As of September 30, October 1, September 30, Accounts receivable — billed (net of allowances for doubtful accounts of $21,211 as of September 30 and October 1, 2018 and $36,121 as of September 30, 2019) $ 707,505 $ 707,505 $ 760,797 Accounts receivable — unbilled (current) $ 263,997 $ 274,036 $ 227,061 Accounts receivable — unbilled (non-current) $ 15,686 $ 13,185 $ 16,987 Total Accounts receivable — unbilled $ 279,683 $ 287,221 $ 244,048 Deferred revenue (current) $ (132,414 ) $ (146,462 ) $ (118,182 ) Deferred revenue (non-current) $ (27,977 ) $ (27,977 ) $ (23,785 ) Total Deferred revenue $ (160,391 ) $ (174,439 ) $ (141,967 ) Revenue recognized during the year ended September 30, 2019, which was included in deferred revenue (current) as of October 1, 2018 was $93,508. Amounts billed during the year ended September 30, 2019, which was included in unbilled accounts receivable (current) as of October 1, 2018, was $129,230. Remaining Performance Obligations from Contracts with Customer As of September 30, 2019, the aggregate amount of the transaction price allocated to remaining performance obligations that are unsatisfied or partially unsatisfied was approximately $5.5 billion. Remaining performance obligations typically include the remaining non-cancelable, Disaggregation of Revenue The Company considers information that is regularly reviewed by its chief operating decision makers in evaluating financial performance to disaggregate revenue, see Note 21 — Segment Information and Sales to Significant Customers.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 5 — Fair Value Measurements The Company accounts for certain assets and liabilities at fair value. Fair value is the price that would be received from selling an asset or that would be paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Company considers the principal or most advantageous market in which it would transact and it considers assumptions that market participants would use when pricing the asset or liability. The hierarchy below lists three levels of fair value based on the extent to which inputs used in measuring fair value are observable in the market. The Company categorizes each of its fair value measurements in one of these three levels based on the lowest level input that is significant to the fair value measurement in its entirety. The three levels of inputs that may be used to measure fair value are as follows: Level 1: Level 2: Level 3: The following tables present the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2019 and 2018: As of September 30, 2019 Level 1 Level 2 Level 3 Total Available-for-sale Money market funds $ 69,370 $ — $ — $ 69,370 Total available-for-sale 69,370 — — 69,370 Equity Investment — — 18,008 18,008 Derivative financial instruments, net — 7,890 — 7,890 Other liabilities — — (29,805 ) (29,805 ) Total $ 69,370 $ 7,890 $ (11,797 ) $ 65,463 As of September 30, 2018 Level 1 Level 2 Level 3 Total Available-for-sale Corporate bonds $ — $ 47,531 $ — $ 47,531 Money market funds 30,883 — — 30,883 U.S. government treasuries 23,258 — — 23,258 U.S. agency securities — 16,033 — 16,033 Asset backed obligations — 9,177 — 9,177 Supranational and sovereign debt — 4,434 — 4,434 Total available-for-sale 54,141 77,175 — 131,316 Derivative financial instruments, net — (27,842 ) — (27,842 ) Other liabilities — — (37,954 ) (37,954 ) Total $ 54,141 $ 49,333 $ (37,954 ) $ 65,520 Available-for-sale non-binding Fair Value of Financial Instruments The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, accrued personnel costs, short-term financing arrangements and accrued expenses and other current liabilities approximate their fair value because of the relatively short maturity of these items.

Available-For-Sale Securities

Available-For-Sale Securities	12 Months Ended
	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Available-For-Sale Securities	Note 6 — Available-For-Sale In fiscal year 2019 the Company sold most of its available-for-sale Available-for-sale As of September 30, 2019 Amortized Gross Gross Fair Value Money market funds $ 69,370 $ — $ — $ 69,370 Total(1) $ 69,370 $ — $ — $ 69,370 (1) Available-for-sale available-for-sale As of September 30, 2018 Amortized Gross Gross Fair Value Corporate bonds $ 48,252 $ — $ 721 $ 47,531 Money market funds 30,883 — — 30,883 U.S. government treasuries 23,656 — 398 23,258 U.S. agency securities 16,297 — 264 16,033 Asset backed obligations 9,312 — 135 9,177 Supranational and sovereign debt 4,508 — 74 4,434 Total(1) $ 132,908 $ — $ 1,592 $ 131,316 (1) Available-for-sale available-for-sale As of September 30, 2019, the unrealized losses attributable to the Company’s available-for-sale As of September 30, 2019, the Company’s available-for-sale Market Value Due within one year $ 69,370

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Note 7 — Derivative Financial Instruments The Company’s risk management strategy includes the use of derivative financial instruments to reduce the volatility of earnings and cash flows associated with changes in foreign currency exchange rates. The Company does not enter into derivative transactions for trading purposes. The Company’s derivatives expose it to credit risks from possible non-performance The Company classifies cash flows from its derivative transactions as cash flows from operating activities in the consolidated statements of cash flow. The table below presents the total volume or notional amounts of the Company’s derivative instruments as of September 30, 2019. Notional values are in U.S. dollars and are translated and calculated based on forward rates as of September 30, 2019 for forward contracts, and based on spot rates as of September 30, 2019 for options. Notional Value* Foreign exchange contracts $ 1,103,169 (*) Gross notional amounts do not quantify risk or represent assets or liabilities of the Company but are used in the calculation of settlements under the contracts. The Company records all derivative instruments on the balance sheet at fair value. For further information, see Note 5 to the consolidated financial statements. The fair value of the open foreign exchange contracts recorded as an asset or a liability by the Company on its consolidated balance sheets as of September 30, 2019 and September 30, 2018, is as follows: As of September 30, 2019 2018 Derivatives designated as hedging instruments Prepaid expenses and other current assets $ 9,344 $ 221 Other noncurrent assets 585 25 Accrued expenses and other current liabilities (2,977 ) (17,681 ) Other noncurrent liabilities (2,072 ) (10,030 ) 4,880 (27,465 ) Derivatives not designated as hedging instruments Prepaid expenses and other current assets 5,086 2,758 Accrued expenses and other current liabilities (2,076 ) (3,135 ) 3,010 (377 ) Net fair value $ 7,890 $ (27,842 ) Cash Flow Hedges In order to reduce the impact of changes in foreign currency exchange rates on its results, the Company enters into foreign currency exchange forward and option contracts to purchase and sell foreign currencies to hedge a significant portion of its foreign currency net exposure resulting from revenue and expense transactions denominated in currencies other than the U.S. dollar. The Company designates these contracts for accounting purposes as cash flow hedges. The Company currently hedges its exposure to the variability in future cash flows for a maximum period of approximately three years. A significant portion of the forward and option contracts outstanding as of September 30, 2019 is scheduled to mature within the next 12 months. The effective portion of the gain or loss on the derivative instruments is initially recorded as a component of other comprehensive income (loss), a separate component of equity, and subsequently reclassified into earnings in the same line item as the related forecasted transaction and in the same period or periods during which the hedged exposure affects earnings. The cash flow hedges are evaluated for effectiveness quarterly. As the critical terms of the forward contract or option and the hedged transaction are matched at inception, the hedge effectiveness is assessed generally based on changes in the fair value for cash flow hedges, as compared to the changes in the fair value of the cash flows associated with the underlying hedged transactions. Hedge ineffectiveness, if any, and hedge components, such as time value, excluded from assessment of effectiveness testing for hedges of estimated revenue from customers, are recognized immediately in interest and other expense, net. The effect of the Company’s cash flow hedging instruments in the consolidated statements of income for the fiscal years ended September 30, 2019, 2018 and 2017, respectively, which partially offsets the foreign currency impact from the underlying exposures, is summarized as follows: (Losses) Gains Reclassified from 2019 2018 2017 Line item in consolidated statements of income: Revenue $ 19 $ (1,129 ) $ (1,021 ) Cost of revenue (8,627 ) 15,877 21,783 Research and development (2,059 ) 3,127 4,282 Selling, general and administrative (2,309 ) 3,462 3,305 Total $ (12,976 ) $ 21,337 $ 28,349 The activity related to the changes in net unrealized gains (losses) on cash flow hedges recorded in accumulated other comprehensive (loss) income, net of tax, is as follows: Year Ended September 30, 2019 2018 2017 Net unrealized (loss) gain on cash flow hedges, net of tax, beginning of period $ (26,608 ) $ 24,508 $ 12,514 Changes in fair value of cash flow hedges, net of tax 19,228 (31,908 ) 36,765 Reclassification of loss (gain) into earnings, net of tax 11,325 (19,208 ) (24,771 ) Net unrealized gain (loss) on cash flow hedges, net of tax, end of period $ 3,945 $ (26,608 ) $ 24,508 Net unrealized gain (loss) from cash flow hedges recognized in other comprehensive income (loss) were $20,035, $(34,260) and $39,692, or $19,228, $(31,908) and $36,765, net of taxes, during the fiscal years ended September 30, 2019, 2018 and 2017, respectively. Of the net gains related to derivatives designated as cash flow hedges and recorded in accumulated other comprehensive (loss) income as of September 30, 2019, a net gain of $5,085 will be reclassified into earnings during fiscal 2020 and will partially offset the foreign currency impact from the underlying exposures. The amount ultimately realized in earnings will likely differ due to future changes in foreign exchange rates. The ineffective portion of the change in fair value of a cash flow hedge, including the time value portion excluded from effectiveness testing for the fiscal years ended September 30, 2019, 2018 and 2017, was not material. Cash flow hedges are required to be discontinued in the event it becomes probable that the underlying forecasted hedged transaction will not occur. The Company did not discontinue any cash flow hedges during any of the periods presented nor does the Company anticipate any such discontinuance in the normal course of business. Other Risk Management Derivatives The Company also enters into foreign currency exchange forward and option contracts that are not designated as hedging instruments under hedge accounting and are used to reduce the impact of foreign currency on certain balance sheet exposures and certain revenue and expense transactions. These instruments are generally short-term in nature, with typical maturities of less than 12 months, and are subject to fluctuations in foreign exchange rates. The effect of the Company’s derivative instruments not designated as hedging instruments in the consolidated statements of income for the fiscal years ended September 30, 2019, 2018 and 2017, respectively, which partially offsets the foreign currency impact from the underlying exposure, is summarized as follows: Gains (Losses) 2019 2018 2017 Line item in statements of income: Cost of revenue $ 401 $ (4,577 ) $ 4,639 Research and development 14 (736 ) 957 Selling, general and administrative 294 (950 ) 1,723 Interest and other income (expense), net 5,845 7,038 (10,514 ) Income taxes (528 ) 1,581 (1,653 ) Total $ 6,026 $ 2,356 $ (4,848 )

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Note 8 — Property and Equipment, Net The components of property and equipment, net are: As of September 30, 2019 2018 Computers, related equipment and software $ 1,109,465 $ 1,027,825 Building and land 109,446 97,782 Leasehold improvements 230,817 222,812 Furniture, fixtures and other 47,813 43,518 Property and equipment, gross 1,497,541 1,391,937 Less accumulated depreciation (972,227 ) (895,352 ) Property and equipment, net $ 525,314 $ 496,585 Total depreciation expense for fiscal years 2019, 2018 and 2017, was $111,387, $105,439 and $105,027, respectively. As of September 30, 2019 and 2018, the costs, net of accumulated depreciation of software assets developed for internal use were $171,331 and $152,366, respectively, and are presented under Computer equipment in the table above. In fiscal year 2018, the Company purchased a land and capitalized costs related to the new building, see also Note 2.

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Net	12 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets, Net	Note 9 — Goodwill and Intangible Assets, Net The following table presents details of the Company’s total goodwill: As of October 1, 2017 $ 2,221,209 Goodwill resulting from acquisitions(1) 227,283 Other (3,597 ) As of September 30, 2018 $ 2,444,895 Goodwill resulting from acquisitions(2) 17,484 Other 456 As of September 30, 2019 $ 2,462,835 (1) Mainly relates to the acquisitions of Vubiquity, projekt202 and UXP. In allocating the total purchase price for Vubiquity, based on estimated fair values, the Company recorded $148,184 of goodwill, $38,630 of customer relationships to be amortized over approximately nine years, $45,692 of core technology to be amortized over approximately five years, $10,104 of trade mark to be amortized over eight years. In allocating the total purchase price of projekt202, based on estimated fair values, the Company recorded $34,390 of goodwill and $19,835 of customer relationships to be amortized over four years. In allocating the total purchase price of UXP, based on estimated fair values, the Company recorded $40,629 of goodwill, $31,552 of core technology to be amortized over five years and $6,552 of customer relationships to be amortized over approximately five years. (2) Mainly relates to the acquisitions of TTS. In allocating the total preliminary purchase price for TTS, based on estimated fair values, the Company recorded $10,032 of goodwill, $29,500 of customer relationships to be amortized over approximately six years, $2,100 of core technology to be amortized over approximately six years and $1,300 of trade mark to be amortized over four years. The Company performs an annual goodwill impairment test during the fourth quarter of each fiscal year, or more frequently if impairment indicators are present. The Company operates in one operating segment, and this segment comprises its only reporting unit. In calculating the fair value of the reporting unit, the Company uses its market capitalization and a discounted cash flow methodology. There was no impairment of goodwill in fiscal years 2019, 2018 or 2017. The following table presents details regarding the Company’s total definite-lived purchased intangible assets: Gross Accumulated Net September 30, 2019 Core technology(1) $ 775,479 $ (690,961 ) $ 84,518 Customer relationships 594,555 (483,313 ) 111,242 Other 44,946 (35,544 ) 9,402 Total $ 1,414,980 $ (1,209,818 ) $ 205,162 September 30, 2018 Core technology(1) $ 773,380 $ (628,932 ) $ 144,448 Customer relationships 563,656 (453,137 ) 110,519 Other 43,646 (33,364 ) 10,282 Total $ 1,380,682 $ (1,115,433 ) $ 265,249 (1) Amounts previously presented separately as Intellectual property rights and purchased computer software are included in Core Technology as the nature of the intangible is consistent with the Core technology category. The asset was fully amortized as of 2019 and 2018, and consisted of gross asset of $51,996 and accumulated amortization of $51,996. The following table presents the amortization expense of the Company’s definite-lived purchased intangible assets, included in each financial statement caption reported in the consolidated statements of income: Year Ended September 30, 2019 2018 2017 Cost of revenue $ 180 $ 572 $ 1,405 Amortization of definite-lived purchased intangible assets 94,205 105,213 108,453 Total $ 94,385 $ 105,785 $ 109,858 The estimated future amortization expense of definite-lived purchased intangible assets as of September 30, 2019 is as follows: Amount Fiscal year: 2020 $ 70,138 2021 47,114 2022 34,940 2023 18,904 2024 11,186 Thereafter 22,880 Total $ 205,162

Non-recurring charges

Non-recurring charges	12 Months Ended
	Sep. 30, 2019
Unusual or Infrequent Items, or Both [Abstract]
Non-recurring charges	Note 10 — Non-recurring During fiscal year 2018 the Company incurred non-recurring

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 11 — Income Taxes The provision (benefit) for income taxes consists of the following: Year Ended September 30, 2019 2018 2017 Current $ 102,391 $ 42,047 $ 69,535 Deferred (13,950 ) 25,098 6,551 Income taxes $ 88,441 $ 67,145 $ 76,086 All income taxes are from continuing operations reported by the Company in the applicable taxing jurisdiction. Income taxes also include anticipated withholding taxes due on subsidiaries’ earnings when paid as dividends to the Company. The Company maintained a tax receivable balance of $53,143 and $55,198 as of September 30, 2019 and 2018, respectively, which is included in Prepaid expenses and other current assets. Deferred income taxes are comprised of the following components: As of September 30, 2019 2018 Deferred tax assets: Deferred revenue $ 30,659 $ 30,596 Employee compensation and benefits 76,327 72,218 Intangible assets, computer software and intellectual property 11,805 9,793 Tax credits, net capital and operating loss carryforwards 153,062 184,450 Other 73,249 49,732 Total deferred tax assets 345,102 346,789 Valuation allowances (85,533 ) (112,727 ) Total deferred tax assets, net 259,569 234,062 Deferred tax liabilities: Anticipated withholdings on subsidiaries’ earnings (70,961 ) (68,394 ) Intangible assets, computer software and intellectual property (104,926 ) (114,094 ) Other (81,736 ) (31,750 ) Total deferred tax liabilities (257,623 ) (214,238 ) Net deferred tax assets $ 1,946 $ 19,824 The effective income tax rate varied from the statutory Guernsey tax rate as follows: Year Ended September 30, 2019 2018 2017 Statutory Guernsey tax rate 0 % 0 % 0 % Foreign taxes(1) 15.6 15.9 14.8 Effective income tax rate 15.6 % 15.9 % 14.8 % As a Guernsey company subject to a corporate tax rate of zero percent, the Company’s overall effective tax rate is attributable to foreign taxes. The Company’s income before income tax expense is considered to be foreign income. Foreign taxes for the year ended Sep 30, 2019: In fiscal year 2019, foreign taxes included a benefit of $26,529 that was primarily attributable to the expiration of the periods set forth in statutes of limitations and to a lesser extent from the conclusions of tax audits related to unrecognized tax benefits accumulated over several years in certain jurisdictions. (1) Foreign taxes in fiscal year 2019 also included a benefit of $12,650 resulting from the release of valuation allowances on deferred tax assets at certain of the Company’s subsidiaries, which will, more likely than not, be realized due to the Company’s projections of future taxable income. Foreign taxes for the year ended Sep 30, 2018: In fiscal year 2018, foreign taxes included a benefit of $9,564 due to conclusions of tax audits in certain jurisdictions, which resulted in an increase to the Company’s tax credits carryforwards and a reduction to the Company’s provision for gross unrecognized tax benefits. In addition, foreign taxes in fiscal year 2018 included a benefit of $18,022 that was attributable to the expiration of the periods set forth in statutes of limitations related to unrecognized tax benefits accumulated over several years in certain jurisdictions. Foreign taxes in fiscal year 2018 also included a tax expenses of $12,032 resulting from the creation of valuation allowances on deferred tax assets at certain of the Company’s subsidiaries, which may not be realized based on the Company’s projections of future taxable income. In addition, foreign taxes in fiscal year 2018 included a provisional expense of $2,321 relating to changes in tax law in the United States pursuant to SAB No. 118 (see Note 2). The provisional expense is attributable to deemed repatriation of foreign income partially offset by a benefit resulting from the re-evaluation As an indirect consequence to the changes in tax law in the United States the Company no longer makes a permanently reinvest assertion relating to one of its subsidiaries, therefore, a provisional tax liability of $4,059 was recorded related to the tax implications of remitting earnings that were previously asserted as permanently reinvested. During fiscal year 2018, as a result of funding decisions for the construction of the Company’s new campus in Israel, see also Note 2, the Company recorded a tax benefit of $28,795 related to the release of withholding and income tax reserves for unremitted earnings. During fiscal year 2019, the net decrease in valuation allowances was $27,194. The valuation allowances, related to the uncertainty of realizing tax benefits primarily for tax credits, net capital and operating loss carryforwards related to certain of the Company’s subsidiaries. As of September 30, 2019, the Company had tax credits, net capital and operating loss carryforwards of $797,091 of which $244,711 have expiration dates through 2039, and the remainder do not expire. During fiscal year 2018, the net increase in valuation allowances was $18,154, which related to the uncertainty of realizing tax benefits primarily for tax credits, net capital and operating loss carryforwards related to certain of the Company’s subsidiaries. As of September 30, 2018, the Company had tax credits, net capital and operating loss carryforwards of $894,997 of which $322,816 have expiration dates through 2038, and the remainder do not expire. The aggregate changes in the balance of the Company’s gross unrecognized tax benefits were as follows: Year Ended September 30, 2019 2018 2017 Balance at beginning of fiscal year $ 187,646 $ 193,024 $ 196,668 Additions based on tax positions related to the current year 19,530 20,329 22,319 Additions (reduction) for tax positions of prior years 24,980 (3,805 ) 12,261 Settlements with tax authorities(1) (37,672 ) (3,880 ) (9,450 ) Lapse of statute of limitations (25,162 ) (18,022 ) (28,774 ) Balance at end of fiscal year $ 169,322 $ 187,646 $ 193,024 (1) The changes in the year ended September 30, 2019, in the balance of the Company’s gross unrecognized tax benefits that relate to settlements with tax authorities is $37,672, the vast majority of which was offset by income tax payments and increase in Tax Payables and Deferred Tax Liabilities. The total amount of unrecognized tax benefits, which includes interest and penalties, was $169,322 as of September 30, 2019, and $187,646 as of September 30, 2018, all of which would affect the effective tax rate if realized. The Company recognizes interest and penalties related to unrecognized tax benefits in the provision for income taxes. As of September 30, 2019, the Company had accrued $31,108 in income taxes payable for interest and penalties relating to unrecognized tax benefits, of which $4,679 was recognized in the statements of income in fiscal year 2019, net of interest and penalty reversals. As of September 30, 2018, the Company had accrued $30,807 in income taxes payable for interest and penalties relating to unrecognized tax benefits, of which a benefit of $2,579 was recognized in the statements of income in fiscal year 2018, net of interest and penalty reversals. The Company is currently under tax audit in several jurisdictions for the tax years 2007 and onwards. Timing of the resolution of audits is highly uncertain and therefore, as of September 30, 2019, the Company cannot estimate the change in unrecognized tax benefits resulting from these audits within the next 12 months. It is reasonably possible that the amount of unrecognized tax benefits may decrease by up to $12,763 during fiscal year 2020 as a result of lapse of statutes of limitations in jurisdictions in which the Company operates.

Repurchase of Shares

Repurchase of Shares	12 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Repurchase of Shares	Note 12 — Repurchase of Shares From time to time, the Company’s Board of Directors can adopt share repurchase plans authorizing the repurchase of the Company’s outstanding ordinary shares. On November 8, 2017, the Company’s Board of Directors adopted another share repurchase plan for the repurchase of up to an additional $800,000 of the Company’s outstanding ordinary shares with no expiration date. In April 2018, the Company completed the repurchase of the remaining authorized amount of ordinary shares under the February 2016 plan and began executing repurchases under the November 2017 plan. In fiscal year 2019, the Company repurchased approximately 6,656 ordinary shares at an average price of $59.79 per share (excluding broker and transaction fees). The November 2017 plan permits the Company to purchase its ordinary shares in open market or privately negotiated transactions at times and prices that it considers appropriate. As of September 30, 2019, the Company had remaining authority to repurchase up to $239,171 of its outstanding ordinary shares under the November 2017 plan. On November 12, 2019, the Company’s Board of Directors adopted another share repurchase plan for the repurchase of up to an additional $800,000 of Company’s outstanding ordinary shares which brings the unused authorization as of September 30, 2019 to $1,039,171. The November 2019 plan authorizations have no expiration date and permit the Company to purchase its ordinary shares in open market or privately negotiated transactions at times and prices that it considers appropriate.

Financing Arrangements

Financing Arrangements	12 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Financing Arrangements	Note 13 — Financing Arrangements In December 2011, the Company entered into a $500,000 five-year revolving credit facility with a syndicate of banks. In December 2014 and in December 2017, the credit facility was amended and restated to, among other things, extend the maturity date of the facility to December 2019 and December 2022, respectively. The credit facility is available for general corporate purposes, including acquisitions and repurchases of ordinary shares that the Company may consider from time to time. The interest rate for borrowings under the revolving credit facility is chosen at the Company’s option from several pre-defined As of September 30, 2019, the Company had additional uncommitted lines of credit available for general corporate and other specific purposes and had outstanding letters of credit and bank guarantees from various banks totaling $91,291. These were supported by a combination of the uncommitted lines of credit that the Company maintains with various banks.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Sep. 30, 2019
Text Block [Abstract]
Accrued Expenses and Other Current Liabilities	Note 14 — Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following: As of September 30, 2019 2018 Ongoing accrued expenses $ 259,661 $ 256,012 Project-related provisions 140,701 155,739 Taxes payable 28,335 27,843 Dividends payable(1) 38,413 35,046 Derivative instruments(2) 5,053 20,821 Other 175,494 211,176 $ 647,657 $ 706,637 (1) The amounts payable as a result of the August 7, 2019 and the July 31, 2018 dividend declarations. See Note 19 to the consolidated financial statements. (2) Includes derivatives that are designated as hedging instruments and derivatives that are not designated as hedging instruments. See Note 7 to the consolidated financial statements.

Interest and other expense, net

Interest and other expense, net	12 Months Ended
	Sep. 30, 2019
Other Income and Expenses [Abstract]
Interest and other expense, net	Note 15 — Interest and other expense, net Interest and other expense, net, consists of the following: Year Ended September 30, 2019 2018 2017 Interest income $ 6,225 $ 6,602 $ 7,972 Interest expense (3,911 ) (2,764 ) (1,600 ) Foreign exchange loss (7,860 ) (6,173 ) (8,246 ) Other, net 3,687 (4,431 ) (2,547 ) $ (1,859 ) $ (6,766 ) $ (4,421 )

Contingencies and Commitments

Contingencies and Commitments	12 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Contingencies and Commitments	Note 16 — Contingencies and Commitments Commitments The Company leases office space and vehicles under non-cancelable non-cancelable For the year ended September 30, 2020 $ 69,043 2021 60,544 2022 51,863 2023 31,951 2024 24,350 Thereafter 93,845 $ 331,596 Rent expense net of sublease income was approximately $65,692, $63,603 and $55,480 for fiscal years 2019, 2018 and 2017, respectively. The Company had immaterial committed future sublease income as of September 30, 2019. Legal Proceedings The Company is involved in various legal claims and proceedings arising in the normal course of its business. The Company accrues for a loss contingency when it determines that it is probable, after consultation with counsel, that a liability has been incurred and the amount of such loss can be reasonably estimated. At this time, the Company believes that the results of any such contingencies, either individually or in the aggregate, will not have a material adverse effect on the Company’s financial position, results of operations or cash flows. Since 2014, the Company has been defending a lawsuit against certain of its subsidiaries in the U.S. District Court in Oregon alleging breach of contract and trade secret misappropriation. According to the suit, the Company improperly utilized information received in connection with its electronic payment processing solution, which is one of several components of its mobile financial services offerings. During fiscal year 2016, the District Court denied the Company’s motions to dismiss and to compel arbitration with respect to certain of the claims, and the proceedings continued. The District Court scheduled a tentative jury trial date for late October 2018. The Company filed a motion for summary judgment with the District Court during fiscal year 2018 and the District Court partially granted the motion with respect to two trade secrets. In October 2018, while continuing to deny the plaintiff’s allegations, the Company entered into a settlement agreement with the plaintiff, which included a $50,000 settlement payment by the Company, in consideration for a mutual release of each party and its respective customers with no admission of liability or fault. As a result of the settlement, the lawsuit was dismissed with prejudice on November 13, 2018. During fiscal year 2019 the Company paid the settlement amount of $50,000 and $5,000 in legal and other fees which were accrued as of September 30, 2018. Certain of the Company’s subsidiaries are currently in a dispute with a state-owned telecom enterprise in Ecuador, which appears to have political aspects. The Company’s counterparty has claimed monetary damages. The dispute is over contracts, under which the Company was providing certain services, which have been terminated by the counterparty in connection with such dispute and which are under scrutiny by certain local governmental authorities. The Company believes it has solid arguments and is vigorously defending its rights. To date, however, such defense efforts, including motions alleging constitutional defects, have encountered a dismissive approach by the Ecuadorian Courts, with reasoning that the Company believes is inconsistent with applicable law. The Company is unable to reasonably estimate the ultimate outcome of the above dispute. Guarantor’s Accounting and Disclosure Requirements for Guarantees In the ordinary course of its business, the Company provides certain customers with financial performance guarantees which, in certain cases, are backed by lines of credit. The Company is only liable for the amounts of those guarantees in the event of the Company’s nonperformance, which would permit the customer to exercise the guarantee. The Company generally offers its products with a limited warranty. The Company’s policy is to accrue for warranty costs, if needed, based on historical trends in product failure. Based on the Company’s experience, only minimal warranty charges have been incurred after revenue was fully recognized and, as a result, the Company did not accrue any amounts for product warranty liability during fiscal years 2019, 2018 and 2017. The Company generally indemnifies its customers against claims made by third parties arising from the use of the Company’s software and certain other matters. To date, the Company has incurred and recorded immaterial costs as a result of such obligations in its consolidated financial statements.

Employee Benefits

Employee Benefits	12 Months Ended
	Sep. 30, 2019
Retirement Benefits [Abstract]
Employee Benefits	Note 17 — Employee Benefits The Company accrues severance pay mainly for the employees of its Israeli operations in accordance with Israeli law and certain employment procedures on the basis of the latest monthly salary paid to these employees and the length of time that they have worked for the Israeli operations. The severance pay liability amounted to $266,209 and $258,262 as of September 30, 2019 and 2018, respectively, and is included as accrued employee costs in other noncurrent liabilities. This liability is partially funded by amounts on deposit with insurance companies that totaled $206,752 and $202,230 as of September 30, 2019 and 2018, respectively, and are included in other noncurrent assets. The accrued severance expenses were $33,355, $28,472 and $32,908 for fiscal years 2019, 2018 and 2017, respectively. The Company sponsors defined contribution plans covering certain of its employees around the world. The plans primarily provide for Company matching contributions based upon a percentage of the employees’ contributions. The Company’s contributions in fiscal years 2019, 2018 and 2017 under such plans were not material compared to total operating expenses. The Company maintains non-contributory pro-rated non-contributory

Stock Option and Incentive Plan

Stock Option and Incentive Plan	12 Months Ended
	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and Incentive Plan	Note 18 — Stock Option and Incentive Plan In January 1998, the Company adopted the 1998 Stock Option and Incentive Plan, or Equity Incentive Plan, which provides for the grant of restricted stock awards, stock options and other equity-based awards to employees, officers, directors, and consultants. Since its adoption, the Equity Incentive Plan has been amended on several occasions to, among other things, increase the number of ordinary shares issuable under the Equity Incentive Plan. In January 2017, the maximum number of ordinary shares authorized by the Company’s Board of Directors to be granted under the Equity Incentive Plan was increased from 62,300 to 67,550. The issuance of such additional shares was registered with the SEC in February 2018. Awards granted under the Equity Incentive Plan generally vest over a period of three to four years and stock options have a term of ten years. Also, in accordance with the Equity Incentive Plan, options are issued at or above the market price at the time of the grant. The following table summarizes information about options to purchase the Company ’ Number of Weighted Average Outstanding as of October 1, 2018 6,418 $ 54.76 Granted 1,975 60.04 Exercised (874 ) 47.41 Forfeited (682 ) 60.52 Outstanding as of September 30, 2019(1) 6,837 $ 56.65 Exercisable as of September 30, 2019(1) 2,899 $ 50.60 (1) As of September 30, 2019, the weighted average remaining contractual life of outstanding and exercisable options was 7.24 and 5.63 years, respectively. The following table summarizes information relating to awards of restricted shares, as well as changes during the fiscal year ended September 30, 2019: Number of Weighted Average Outstanding as of October 1, 2018 1,022 $ 60.68 Granted 521 61.65 Vested (459 ) 59.32 Forfeited (147 ) 61.86 Outstanding as of September 30, 2019 937 $ 61.70 The total intrinsic value of options exercised during fiscal years 2019, 2018 and 2017 was $13,081, $38,025 and $47,321, respectively. The value of restricted shares vested during fiscal years 2019, 2018 and 2017 was $28,430, $35,801 and $36,922, respectively. The aggregate intrinsic value of outstanding and exercisable stock options as of September 30, 2019 was $56,997 and $40,532, respectively. Employee equity-based compensation pre-tax Year Ended September 30, 2019 2018 2017 Cost of revenue $ 19,879 $ 18,253 $ 19,215 Research and development 2,714 3,476 3,536 Selling, general and administrative 15,957 25,747 21,788 Total $ 38,550 $ 47,476 $ 44,539 The fair value of options granted was estimated on the date of grant using the Black-Scholes pricing model with the assumptions noted in the following table (all in weighted averages for options granted during the year): Year Ended September 30, 2019 2018 2017 Risk-free interest rate(1) 2.64 % 2.30 % 1.63 % Expected life of stock options(2) 4.50 4.50 4.50 Expected volatility(3) 17.8 % 15.0 % 16.2 % Expected dividend yield(4) 1.82 % 1.51 % 1.47 % Fair value per option $ 9.13 $ 8.70 $ 7.62 (1) Risk-free interest rate is based upon U.S. Treasury yield curve appropriate for the term of the Company’s employee stock options. (2) Expected life of stock options is based upon historical experience. (3) Expected volatility is based on blended volatility. (4) Expected dividend yield is based on the Company’s history and future expectation of dividend payouts.

Dividends

Dividends	12 Months Ended
	Sep. 30, 2019
Other Liabilities Disclosure [Abstract]
Dividends	Note 19 — Dividends The Company’s Board of Directors declared the following dividends during the fiscal years ended September 30, 2019, 2018 and 2017: Declaration Date Dividends Per Record Date Total Amount Payment Date August 7, 2019 $ 0.285 September 30, 2019 $ 38,413 October 25, 2019 May 14, 2019 $ 0.285 June 28, 2019 $ 38,730 July 19, 2019 February 5, 2019 $ 0.285 March 29, 2019 $ 39,084 April 19, 2019 November 8, 2018 $ 0.250 December 31, 2018 $ 34,755 January 18, 2019 July 31, 2018 $ 0.250 September 28, 2018 $ 35,046 October 19, 2018 May 10, 2018 $ 0.250 June 29, 2018 $ 35,363 July 20, 2018 January 30, 2018 $ 0.250 March 30, 2018 $ 35,637 April 20, 2018 November 8, 2017 $ 0.220 December 29, 2017 $ 31,556 January 19, 2018 August 2, 2017 $ 0.220 September 29, 2017 $ 31,736 October 23, 2017 May 9, 2017 $ 0.220 June 30, 2017 $ 31,981 July 14, 2017 February 1, 2017 $ 0.220 March 31, 2017 $ 32,223 April 14, 2017 November 8, 2016 $ 0.195 December 30, 2016 $ 28,606 January 13, 2017 The amounts payable as a result of the August 7, 2019, July 31, 2018 and August 2, 2017 declarations were included in accrued expenses and other current liabilities as of September 30, 2019, 2018 and 2017, respectively. On November 12, 2019, the Company’s Board of Directors approved quarterly dividend payment of $0.285 per share, and set December 31, 2019 as the record date for determining the shareholders entitled to receive the dividend, which is payable on January 24, 2020. On November 12, 2019, the Company’s Board of Directors also approved, subject to shareholder approval at the January 2020 annual general meeting of shareholders, an increase in the quarterly cash dividend to $0.3275 per share, anticipated to be paid in April 2020.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Note 20 — Earnings Per Share The following table sets forth the computation of basic and diluted earnings per share: Year Ended September 30, 2019 2018 2017 Numerator: Net income $ 479,446 $ 354,396 $ 436,826 Net income and dividends attributable to participating restricted shares (3,295 ) (2,650 ) (3,517 ) Numerator for basic earnings per common share $ 476,151 $ 351,746 $ 433,309 Undistributed income allocated to participating restricted shares 2,252 1,617 2,512 Undistributed income reallocated to participating restricted shares (2,240 ) (1,603 ) (2,488 ) Numerator for diluted earnings per common share $ 476,163 $ 351,760 $ 433,333 Denominator: Weighted average number of shares outstanding — basic 137,418 142,422 146,017 Weighted average number of participating restricted shares (944 ) (1,065 ) (1,176 ) Weighted average number of common shares — basic 136,474 141,357 144,841 Effect of dilutive stock options granted 691 1,282 1,414 Weighted average number of common shares — diluted 137,165 142,639 146,255 Basic earnings per common share $ 3.49 $ 2.49 $ 2.99 Diluted earnings per common share $ 3.47 $ 2.47 $ 2.96 For the fiscal years ended September 30, 2019, 2018 and 2017, 3,547, 1,357 and 1,281 shares, respectively, on a weighted average basis, were attributable to antidilutive outstanding stock options and therefore were not included in the calculation of diluted earnings per share.

Segment Information and Sales t

Segment Information and Sales to Significant Customers	12 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Information and Sales to Significant Customers	Note 21 — Segment Information and Sales to Significant Customers The Company and its subsidiaries operate in one operating segment, providing software products and services for the communications, entertainment and media industry service providers. Geographic Information The following is a summary of revenue and long-lived assets by geographic area. Revenue is attributed to geographic region based on the location of the customers. Year Ended September 30, 2019 2018 2017 Revenue North America (mainly United States) $ 2,582,719 $ 2,550,234 $ 2,546,290 Europe 598,731 572,196 488,932 Rest of the world 905,219 852,407 831,933 Total $ 4,086,669 $ 3,974,837 $ 3,867,155 As of September 30, 2019 2018 Long-lived Assets(1) Europe $ 206,086 $ 187,884 North America 95,876 88,251 Rest of the world: Israel 168,493 161,726 India 36,546 37,239 Others 18,313 21,485 Total $ 525,314 $ 496,585 (1) Property and equipment, net. Revenue by nature of activities Year Ended September 30, 2019 2018 2017 Managed services arrangements $ 2,246,279 $ 2,051,589 $ 2,005,382 Others 1,840,390 1,923,248 1,861,773 Total $ 4,086,669 $ 3,974,837 $ 3,867,155 Sales to Significant Customers The Company had one customer, AT&T, which accounted for at least ten percent of its total revenue in each of fiscal years 2019, 2018 and 2017. The percentage of revenue from this customer out of total revenue during fiscal years 2019, 2018 and 2017 was 23%, 27% and 33%, respectively.

Selected Quarterly Results of O

Selected Quarterly Results of Operations (Unaudited)	12 Months Ended
	Sep. 30, 2019
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Results of Operations (Unaudited)	Note 22 — Selected Quarterly Results of Operations (Unaudited) The following are details of the unaudited quarterly results of operations for the three months ended: September 30, June 30, March 31, December 31, 2019 Revenue $ 1,030,253 $ 1,024,704 $ 1,019,657 $ 1,012,055 Operating income 144,154 142,320 150,175 133,097 Net income 122,027 131,448 124,279 101,692 Basic earnings per share 0.90 0.96 0.90 0.73 Diluted earnings per share 0.90 0.96 0.90 0.72 2018 Revenue $ 1,002,588 $ 1,002,198 $ 992,340 $ 977,711 Operating income 68,819 105,518 131,827 122,143 Net income 44,266 91,530 101,727 116,873 Basic earnings per share 0.31 0.64 0.71 0.81 Diluted earnings per share 0.31 0.64 0.70 0.80

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Sep. 30, 2019
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	VALUATION AND QUALIFYING ACCOUNTS (In thousands) Accounts Receivable Valuation Allowances on Balance as of September 30, 2016 $ 39,512 $ 96,870 Charged to costs and expenses 17,282 16,425 Charged to other accounts 1,985 5,000 (1) Deductions (30,053 )(3) (23,722 )(2) Balance as of September 30, 2017 28,726 94,573 Charged to costs and expenses 6,134 18,173 Charged to other accounts 1,226 6,121 (1) Deductions (14,875 )(4) (6,140 ) Balance as of September 30, 2018 21,211 112,727 Charged to costs and expenses 22,260 1,009 Charged to other accounts 2,406 6,008 (1) Deductions (9,756 )(6) (34,211 )(5) Balance as of September 30, 2019 $ 36,121 $ 85,533 (1) Includes valuation allowances on deferred tax assets incurred in connection with an acquisition. (2) $2,416 of valuation allowances on deferred tax assets were written off against the related deferred tax assets, and the remaining deductions in the valuation allowances on net deferred tax assets were released to earnings. (3) $3,008 of accounts receivable allowances were written off against the related accounts receivables, $5,291 of accounts receivable allowances were netted against deferred revenue, and the remaining deductions in the accounts receivable allowances were released to earnings. (4) $6,659 of accounts receivable allowances were written off against the related accounts receivables, and the remaining deductions in the accounts receivable allowances were released to earnings. (5) $7,588 of valuation allowances on deferred tax assets were written off against the related deferred tax assets, and the remaining deductions in the valuation allowances on net deferred tax assets were released to earnings. (6) $3,539 of accounts receivable allowances were written off against the related accounts receivables, and the remaining deductions in the accounts receivable allowances were released to earnings.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles, or GAAP and are denominated in U.S. Dollars.
Consolidation	Consolidation The consolidated financial statements include the accounts of the Company and its subsidiaries, the vast majority of which are wholly-owned. All intercompany transactions and balances have been eliminated in consolidation. In December 2017, the Company entered into agreements with Union Investments and Development Limited (“Union”) to partner through a legal entity that is equally owned by the Company and Union for the purpose of acquiring specific land which the Company expects to use as the site for a new campus in Ra’anana, Israel. On January 2, 2018 the Company completed the acquisition of the land. Pursuant to the agreements between the Company and Union, as the Company has control over the construction and ongoing operations of the new campus, the new entity’s financial information is consolidated into the Company’s consolidated financial statements with the portion not owned classified as non-controlling
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the dates of the financial statements, and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Reclassifications	Reclassifications From time to time, certain immaterial amounts in prior year financial statements may be reclassified to conform to the current year presentation.
Functional Currency	Functional Currency The Company manages its foreign subsidiaries as integral direct components of its operations. The operations of the Company’s foreign subsidiaries provide the same type of services with the same type of expenditures throughout the Amdocs group. The Company has determined that its functional currency is the U.S. dollar. The Company periodically assesses the applicability of the U.S. dollar as the Company’s functional currency by reviewing the salient indicators as indicated in the authoritative guidance for foreign currency matters.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash and interest-bearing investments with insignificant interest rate risk and maturities from acquisition date of 90 days or less.
Accounts Receivable Factoring	Accounts Receivable Factoring From time to time, the Company uses non-recourse
Investments	Investments The Company classifies all of its short-term interest-bearing investments as available-for-sale first-in-first-out
Property and Equipment	Property and Equipment Property and equipment are stated at cost. Depreciation is computed using the straight-line method over the estimated useful life of the asset, which primarily ranges from three to ten years. Leasehold improvements are amortized over the shorter of the estimated useful lives or the term of the related lease. Property and equipment that have been fully depreciated and are no longer in use are netted against accumulated depreciation. The Company capitalizes certain expenditures for software that is internally developed for use in the business, which is classified as computer equipment. Amortization of internal use software begins when the software is ready for service and continues on the straight-line method over the estimated useful life. The Company capitalizes the expenditures related to the new campus in Israel, which are classified as building and land. Amortization will begin when the new campus is ready for use and will be amortized on the straight-line basis over the estimated useful life.
Goodwill, Intangible Assets and Long-Lived Assets	Goodwill, Intangible Assets and Long-Lived Assets Goodwill and intangible assets deemed to have indefinite lives are subject to an annual impairment test or more frequently if impairment indicators are present. Goodwill impairment is deemed to exist if the net book value of a reporting unit exceeds its estimated fair value. The goodwill impairment test involves a two-step The total purchase price of business acquisitions accounted for using the purchase method is allocated first to identifiable assets and liabilities based on estimated fair values. The excess of the purchase price over the fair value of net assets of purchased businesses is recorded as goodwill. Other definite-life intangible assets consist primarily of core technology and customer relationships. Core technology acquired by the Company is amortized over its estimated useful life on a straight-line basis. Some of the acquired customer relationships are amortized over their estimated useful lives in proportion to the economic benefits realized. This accounting policy generally results in accelerated amortization of such customer relationships as compared to the straight-line method. All other acquired customer relationships are amortized over their estimated useful lives on a straight-line basis. The Company tests long-lived assets, including definite life intangible assets, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability of long-lived assets is based on an estimate of the undiscounted future cash flows resulting from the use of the cash generating unit and its eventual disposition. Measurement of an impairment loss for long-lived assets, including definite life intangible assets that management expects to hold and use is based on the fair value of the cash generating unit. Long-lived assets, including definite life intangible assets, to be disposed of are reported at the lower of carrying amount or fair value less costs to sell.
Comprehensive Income	Comprehensive Income Comprehensive income, net of related taxes where applicable, includes, in addition to net income: (i) net change in fair value of available-for-sale (ii) net change in fair value of cash flow hedges; and (iii) net actuarial gains and losses on defined benefit plans.
Treasury Stock	Treasury Stock The Company repurchases its ordinary shares from time to time on the open market or in other transactions and holds such shares as treasury stock. The Company presents the cost to repurchase treasury stock as a reduction of equity.
Business Combinations	Business Combinations In accordance with business combinations accounting, assets acquired and liabilities assumed, as well as any contingent consideration that may be part of the acquisition agreement, are recorded at their respective fair values at the date of acquisition. For acquisitions that include contingent consideration, the fair value is estimated on the acquisition date as the present value of the expected contingent payments, determined using weighted probabilities of possible payments. The Company remeasures the fair value of the contingent consideration at each reporting period until the contingency is resolved. Except for measurement period adjustments, the changes in fair value are recognized in the consolidated statements of income. Any earn-out In accordance with business combinations accounting, the Company allocates the purchase price of acquired companies to the tangible and intangible assets acquired and liabilities assumed, as well as to in-process Although the Company believes the assumptions and estimates of fair value it has made in the past have been reasonable and appropriate, they are based in part on historical experience and information obtained from the management of the acquired companies and are inherently uncertain and subject to refinement. Critical estimates in valuing certain assets acquired and liabilities assumed include but are not limited to: future expected cash flows from license and service sales, maintenance, customer contracts and acquired developed technologies, expected costs to develop the in-process The Company estimates the fair values of its services, hardware, software license and maintenance obligations assumed. The estimated fair values of these performance obligations are determined utilizing a cost build-up build-up The Company may establish a valuation allowance for certain deferred tax assets and estimate the value of uncertain tax positions of a newly acquired entity. This process requires significant judgment and analysis.
Income Taxes	Income Taxes The Company records deferred income taxes to reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting and tax purposes. Deferred taxes are computed based on enacted tax rates anticipated to be in effect when the deferred taxes are expected to be paid or realized. A valuation allowance is provided for deferred tax assets if it is more likely than not, the Company will not be able to realize their benefit. Deferred tax liabilities and assets are classified as noncurrent on the balance sheet. Deferred tax liabilities also include anticipated withholding taxes due on subsidiaries’ earnings when paid as dividends to the Company. The Company recognizes the tax benefit from an uncertain tax position only if the weight of available evidence indicates that it is more likely than not that the position will be sustained on audit, including resolution of related appeals or litigation processes, if any. The tax benefits recognized in the financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Interest and penalties related to uncertain tax positions are recognized in the provision for income taxes. See Note 11 to the consolidated financial statements.
Revenue Recognition	Revenue Recognition The Company recognizes revenue under the five-step methodology required under ASC 606, which requires the Company to identify the contract with the customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations identified, and recognize revenue when (or as) each performance obligation is satisfied. Revenue is recognized net of any revenue-based taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction and collected by the Company from a customer (for example, sales, use and value added taxes). The Company’s primary revenue categories, related performance obligations, and associated recognition patterns are as follows: Revenue Recognition for projects As a significant portion of the Company’s revenue is satisfied over time as work progresses, the annual and quarterly operating results may be affected by the size and timing of the initiation of customer projects as well as the Company’s progress in completing such projects. Revenue Recognition for subsequent license fee Revenue Recognition for term-based license and perpetual license Revenue Recognition for maintenance Revenue Recognition for ongoing services — Revenue Recognition for managed services arrangement end-to-end The revenue from managed services arrangement is recognized for each individual performance obligation according to its relevant revenue category, including but not limited to, revenue from the management of a customer’s operations, revenue from projects and revenue from ongoing support services. Revenue from the management of a customer’s operations pursuant to managed services arrangements, is recognized over time as services are preformed, using one method of measuring performance such as time elapsed, output produced, volume of data processed or subscriber count that provides the most faithful depiction of the transfer of services, pursuant to the specific contract terms of the managed services arrangement. Typically, managed services arrangements are long term in duration and are not subject to significant seasonality. Revenue Recognition for third-party hardware and software Arrangements with Multiple Performance Obligations Billing terms and conditions generally vary by contract category. Amounts are typically billed as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals (e.g., monthly or quarterly) or upon achievement of contractual milestones. In cases where timing of revenue recognition significantly differs from the timing of invoicing, the Company is considering whether a significant financing component exists. The Company elected to use the practical expedient in assessing the financing component in contracts where the time between cash collection and performance is less than one year. Accounts Receivable — Billed Accounts Receivable — Unbilled — Deferred Revenue — Assets Recognized from the Costs to Obtain a Contract with a Customer — pro-rata In certain circumstances where the Company enters into a contract with a customer for the provision of managed services for a defined period of time, the Company defers certain direct costs incurred at the inception of the contract. These costs include expenses incurred in association with the origination of a contract. In addition, if the revenue for a delivered item is not recognized because it is not separable from the undelivered item, then the Company also defers the cost of the delivered item. The deferred costs are amortized on a straight-line basis over the managed services period, or over the recognition period of the undelivered item. Revenue associated with these capitalized costs is deferred and is recognized over the same period.
Cost of Revenue	Cost of Revenue Cost of revenue consists of all costs associated with providing software licenses and services to customers, third party hardware and software including identified losses on contracts. Estimated losses on contracts satisfied over time as work performed are recognized in the period in which the loss is identified. Cost of revenue also includes costs of third-party products associated with selling third-party computer hardware and software products to customers and other third-party services, when the related revenue is recorded at the gross amount. Customers purchasing third-party products and services from the Company generally do so in conjunction with the purchase of the Company’s software and services.
Research and Development	Research and Development Research and development expenditures consist of costs incurred in the development of new software modules and product offerings, either as part of the Company’s internal product development programs, which are sold, leased or otherwise marketed. Research and development costs are expensed as incurred. Based on the Company’s product development process, technological feasibility is established upon completion of a detailed program design or, in the absence thereof, completion of a working model. Costs incurred by the Company after achieving technological feasibility and before the product is ready for customer release have been insignificant.
Equity-Based Compensation	Equity-Based Compensation The Company measures and recognizes the compensation expense for all equity-based payments to employees and directors based on their estimated fair values. The Company estimates the fair value of employee stock options at the date of grant using a Black-Scholes valuation model and values restricted stock based on the market value of the underlying shares at the date of grant. The Company recognizes compensation costs using the graded vesting attribution method that results in an accelerated recognition of compensation costs in comparison to the straight-line method. The Company uses a combination of implied volatility of the Company’s traded options and historical stock price volatility (“blended volatility”) as the expected volatility assumption required in the Black-Scholes option valuation model. As equity-based compensation expense recognized in the Company’s consolidated statements of income is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash and cash equivalents, short-term interest-bearing investments, and trade receivables. Cash and cash equivalents are maintained with several financial institutions. Generally, these deposits may be redeemed upon demand and are maintained with financial institutions with reputable credit and therefore bear minimal credit risk. The Company seeks to mitigate its credit risks by spreading such risks across multiple financial institutions and monitoring the risk profiles of these counterparties. The Company has conservative investment policy guidelines under which it invests its excess cash primarily in highly liquid U.S. dollar-denominated securities. The Company’s revenue is generated primarily in North America. To a lesser extent, revenue is generated in Europe and the rest of the world. Most of the Company’s customers are among the largest communications and media companies in the world (or are owned by them). The Company’s business is subject to the effects of general global economic conditions and market conditions in the communications industry. The Company performs ongoing credit analyses of its customer base and generally does not require collateral. The Company evaluates accounts receivable to determine if they ultimately will be collected. Significant judgments and estimates are involved in performing this evaluation, which are based on factors that may affect a customer’s ability to pay, such as past experience, credit quality of the customer, age of the receivable balance and current economic conditions. The allowance for doubtful accounts is for estimated losses resulting from accounts receivable for which their collection is not reasonably probable. The allowance for doubtful accounts as of September 30, 2019 and 2018, was $36,121 and $21,211, respectively. As of September 30, 2019, the Company had one customer with an accounts receivable balance of more than 10% of total accounts receivable, amounting to 16%, which was lower than its respective portion of total revenue. As of September 30, 2018, the Company had one customer with an accounts receivable balance of more than 10% of total accounts receivable, amounting to 19%, which was lower than its respective portion of total revenue.
Earnings per Share	Earnings per Share Basic earnings per share is calculated using the weighted average number of shares outstanding during the period. Diluted earnings per share is computed on the basis of the weighted average number of shares outstanding and the effect of dilutive outstanding equity-based awards using the treasury stock method. The Company includes participating securities (unvested restricted shares that contain non-forfeitable two-class
Derivatives and Hedging	Derivatives and Hedging The Company carries out transactions involving foreign currency exchange derivative financial instruments. The transactions are designed to hedge the Company’s exposure in currencies other than the U.S. dollar. The Company recognizes derivative instruments as either assets or liabilities and measures those instruments at fair value. If a derivative meets the definition of a cash flow hedge and is so designated, changes in the fair value of the derivative are recognized in other comprehensive income (loss) until the hedged item is recognized in earnings. The ineffective portion of a derivative designated as a cash flow hedge is recognized in earnings. If a derivative does not meet the definition of a cash flow hedge, the changes in the fair value are included in earnings.
Recent Accounting Standards	Recent Accounting Standards In November 2018, the Financial Accounting Standards Board, or FASB, issued Accounting Standard Update, or ASU, No. 2018-18 , “Collaborative Arrangements In August 2018, the FASB issued ASU No. 2018-15 , “Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract”. internal-use In August 2018, the FASB issued ASU No. 2018-13 , “Fair Value Measurement”. In August 2018, the FASB issued ASU No. 2018-14, Changes to the Disclosure Requirements for Defined Benefit Plans” In June 2018, the FASB issued ASU No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting ” In August 2017, the FASB issued ASU No. 2017-12, Targeted Improvements to Accounting for Hedging Activities ” In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments ” off-balance In February 2016, the FASB issued ASU No. 2016-02, “Leases”.
Adoption of New Accounting Standards	Adoption of New Accounting Standards In December 2017, the SEC issued Staff Accounting Bulletin No. 118 (“SAB No. 118”) in response to the new tax legislation in the United States (The Tax Cuts and Jobs Act or “The Act”). The Act, which was enacted on December 22, 2017, reduces the US federal corporate tax rate from 35% to 21%, which requires the payment of a one-time one-year one-time In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business In October 2016, the FASB issued ASU No. 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments ” . In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments — Overall ” In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers”. The cumulative impact of adopting ASC 606, which was immaterial, was a net increase in the opening balance of retained earnings as of October 1, 2018, of $14,294, net of tax, from total amount of $4,673,901 to $4,688,195. The impact was primarily related to (i) the removal of the limitation on contingent revenue, as revenue allocated to satisfied performance obligations is no longer restricted to the amount that is not contingent upon the satisfaction of additional performance obligations (ii) the change of definition of contract term to represent the period for which enforceable rights and obligations exist, and (iii) the capitalization and amortization of certain sales commissions in accordance with ASC 606. The following table depicts the impact of adoption as of October 1, 2018, on the Company’s consolidated balance sheet: As of October 1, 2018 Balance as of Adjustments due Balance as of Balance Sheet: Account receivable — unbilled $ 263,997 $ 10,039 $ 274,036 Prepaid expenses and other current assets 229,999 (971 ) 229,028 Other noncurrent assets 420,369 15,636 436,005 Deferred revenue (current) 132,414 14,048 146,462 Accrued expenses and other current liabilities 706,637 (14,062 ) 692,575 Deferred income taxes and taxes payable 224,572 10,424 234,996 Retained Earnings 4,673,901 14,294 4,688,195 The impact of adopting the new standard for the year ended September 30, 2019; was an increase of approximately $26,096 to revenue, most of which was recorded against Account receivable — unbilled and decrease of approximately $11,051 to cost of revenue most of which was recorded against Accrued expenses and other current liabilities.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Impact of Adoption of ASC 606 on Consolidated Balance Sheet	The following table depicts the impact of adoption as of October 1, 2018, on the Company’s consolidated balance sheet: As of October 1, 2018 Balance as of Adjustments due Balance as of Balance Sheet: Account receivable — unbilled $ 263,997 $ 10,039 $ 274,036 Prepaid expenses and other current assets 229,999 (971 ) 229,028 Other noncurrent assets 420,369 15,636 436,005 Deferred revenue (current) 132,414 14,048 146,462 Accrued expenses and other current liabilities 706,637 (14,062 ) 692,575 Deferred income taxes and taxes payable 224,572 10,424 234,996 Retained Earnings 4,673,901 14,294 4,688,195

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Summary of Accounts Receivable and Deferred Revenue	The following table provides information about Accounts receivable, both billed and unbilled and deferred revenue: As of September 30, October 1, September 30, Accounts receivable — billed (net of allowances for doubtful accounts of $21,211 as of September 30 and October 1, 2018 and $36,121 as of September 30, 2019) $ 707,505 $ 707,505 $ 760,797 Accounts receivable — unbilled (current) $ 263,997 $ 274,036 $ 227,061 Accounts receivable — unbilled (non-current) $ 15,686 $ 13,185 $ 16,987 Total Accounts receivable — unbilled $ 279,683 $ 287,221 $ 244,048 Deferred revenue (current) $ (132,414 ) $ (146,462 ) $ (118,182 ) Deferred revenue (non-current) $ (27,977 ) $ (27,977 ) $ (23,785 ) Total Deferred revenue $ (160,391 ) $ (174,439 ) $ (141,967 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurement on Company's Assets and Liabilities	The following tables present the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2019 and 2018: As of September 30, 2019 Level 1 Level 2 Level 3 Total Available-for-sale Money market funds $ 69,370 $ — $ — $ 69,370 Total available-for-sale 69,370 — — 69,370 Equity Investment — — 18,008 18,008 Derivative financial instruments, net — 7,890 — 7,890 Other liabilities — — (29,805 ) (29,805 ) Total $ 69,370 $ 7,890 $ (11,797 ) $ 65,463 As of September 30, 2018 Level 1 Level 2 Level 3 Total Available-for-sale Corporate bonds $ — $ 47,531 $ — $ 47,531 Money market funds 30,883 — — 30,883 U.S. government treasuries 23,258 — — 23,258 U.S. agency securities — 16,033 — 16,033 Asset backed obligations — 9,177 — 9,177 Supranational and sovereign debt — 4,434 — 4,434 Total available-for-sale 54,141 77,175 — 131,316 Derivative financial instruments, net — (27,842 ) — (27,842 ) Other liabilities — — (37,954 ) (37,954 ) Total $ 54,141 $ 49,333 $ (37,954 ) $ 65,520

Available-For-Sale Securities (

Available-For-Sale Securities (Tables)	12 Months Ended
	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Interest-Bearing Investments in Available-for-Sale Securities	Available-for-sale As of September 30, 2019 Amortized Gross Gross Fair Value Money market funds $ 69,370 $ — $ — $ 69,370 Total(1) $ 69,370 $ — $ — $ 69,370 (1) Available-for-sale available-for-sale As of September 30, 2018 Amortized Gross Gross Fair Value Corporate bonds $ 48,252 $ — $ 721 $ 47,531 Money market funds 30,883 — — 30,883 U.S. government treasuries 23,656 — 398 23,258 U.S. agency securities 16,297 — 264 16,033 Asset backed obligations 9,312 — 135 9,177 Supranational and sovereign debt 4,508 — 74 4,434 Total(1) $ 132,908 $ — $ 1,592 $ 131,316 (1) Available-for-sale available-for-sale
Available-for-Sale Securities Debt Maturities Market Value	As of September 30, 2019, the Company’s available-for-sale Market Value Due within one year $ 69,370

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Derivative Instruments	The table below presents the total volume or notional amounts of the Company’s derivative instruments as of September 30, 2019. Notional values are in U.S. dollars and are translated and calculated based on forward rates as of September 30, 2019 for forward contracts, and based on spot rates as of September 30, 2019 for options. Notional Value* Foreign exchange contracts $ 1,103,169 (*) Gross notional amounts do not quantify risk or represent assets or liabilities of the Company but are used in the calculation of settlements under the contracts.
Fair Value of Open Foreign Currency Exchange Contracts	The fair value of the open foreign exchange contracts recorded as an asset or a liability by the Company on its consolidated balance sheets as of September 30, 2019 and September 30, 2018, is as follows: As of September 30, 2019 2018 Derivatives designated as hedging instruments Prepaid expenses and other current assets $ 9,344 $ 221 Other noncurrent assets 585 25 Accrued expenses and other current liabilities (2,977 ) (17,681 ) Other noncurrent liabilities (2,072 ) (10,030 ) 4,880 (27,465 ) Derivatives not designated as hedging instruments Prepaid expenses and other current assets 5,086 2,758 Accrued expenses and other current liabilities (2,076 ) (3,135 ) 3,010 (377 ) Net fair value $ 7,890 $ (27,842 )
Effect of Cash Flow Hedging Instruments	The effect of the Company’s cash flow hedging instruments in the consolidated statements of income for the fiscal years ended September 30, 2019, 2018 and 2017, respectively, which partially offsets the foreign currency impact from the underlying exposures, is summarized as follows: (Losses) Gains Reclassified from 2019 2018 2017 Line item in consolidated statements of income: Revenue $ 19 $ (1,129 ) $ (1,021 ) Cost of revenue (8,627 ) 15,877 21,783 Research and development (2,059 ) 3,127 4,282 Selling, general and administrative (2,309 ) 3,462 3,305 Total $ (12,976 ) $ 21,337 $ 28,349
Changes in Net Unrealized (Losses) Gains on Cash Flow Hedges	The activity related to the changes in net unrealized gains (losses) on cash flow hedges recorded in accumulated other comprehensive (loss) income, net of tax, is as follows: Year Ended September 30, 2019 2018 2017 Net unrealized (loss) gain on cash flow hedges, net of tax, beginning of period $ (26,608 ) $ 24,508 $ 12,514 Changes in fair value of cash flow hedges, net of tax 19,228 (31,908 ) 36,765 Reclassification of loss (gain) into earnings, net of tax 11,325 (19,208 ) (24,771 ) Net unrealized gain (loss) on cash flow hedges, net of tax, end of period $ 3,945 $ (26,608 ) $ 24,508
Effect of Non-Designated as Hedging Instruments	The effect of the Company’s derivative instruments not designated as hedging instruments in the consolidated statements of income for the fiscal years ended September 30, 2019, 2018 and 2017, respectively, which partially offsets the foreign currency impact from the underlying exposure, is summarized as follows: Gains (Losses) 2019 2018 2017 Line item in statements of income: Cost of revenue $ 401 $ (4,577 ) $ 4,639 Research and development 14 (736 ) 957 Selling, general and administrative 294 (950 ) 1,723 Interest and other income (expense), net 5,845 7,038 (10,514 ) Income taxes (528 ) 1,581 (1,653 ) Total $ 6,026 $ 2,356 $ (4,848 )

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
Components of Property and Equipment, Net	The components of property and equipment, net are: As of September 30, 2019 2018 Computers, related equipment and software $ 1,109,465 $ 1,027,825 Building and land 109,446 97,782 Leasehold improvements 230,817 222,812 Furniture, fixtures and other 47,813 43,518 Property and equipment, gross 1,497,541 1,391,937 Less accumulated depreciation (972,227 ) (895,352 ) Property and equipment, net $ 525,314 $ 496,585

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets, Net (Tables)	12 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Details of Total Goodwill	The following table presents details of the Company’s total goodwill: As of October 1, 2017 $ 2,221,209 Goodwill resulting from acquisitions(1) 227,283 Other (3,597 ) As of September 30, 2018 $ 2,444,895 Goodwill resulting from acquisitions(2) 17,484 Other 456 As of September 30, 2019 $ 2,462,835 (1) Mainly relates to the acquisitions of Vubiquity, projekt202 and UXP. In allocating the total purchase price for Vubiquity, based on estimated fair values, the Company recorded $148,184 of goodwill, $38,630 of customer relationships to be amortized over approximately nine years, $45,692 of core technology to be amortized over approximately five years, $10,104 of trade mark to be amortized over eight years. In allocating the total purchase price of projekt202, based on estimated fair values, the Company recorded $34,390 of goodwill and $19,835 of customer relationships to be amortized over four years. In allocating the total purchase price of UXP, based on estimated fair values, the Company recorded $40,629 of goodwill, $31,552 of core technology to be amortized over five years and $6,552 of customer relationships to be amortized over approximately five years. (2) Mainly relates to the acquisitions of TTS. In allocating the total preliminary purchase price for TTS, based on estimated fair values, the Company recorded $10,032 of goodwill, $29,500 of customer relationships to be amortized over approximately six years, $2,100 of core technology to be amortized over approximately six years and $1,300 of trade mark to be amortized over four years.
Details Regarding Total Definite-Lived Purchased Intangible Assets	The following table presents details regarding the Company’s total definite-lived purchased intangible assets: Gross Accumulated Net September 30, 2019 Core technology(1) $ 775,479 $ (690,961 ) $ 84,518 Customer relationships 594,555 (483,313 ) 111,242 Other 44,946 (35,544 ) 9,402 Total $ 1,414,980 $ (1,209,818 ) $ 205,162 September 30, 2018 Core technology(1) $ 773,380 $ (628,932 ) $ 144,448 Customer relationships 563,656 (453,137 ) 110,519 Other 43,646 (33,364 ) 10,282 Total $ 1,380,682 $ (1,115,433 ) $ 265,249 (1) Amounts previously presented separately as Intellectual property rights and purchased computer software are included in Core Technology as the nature of the intangible is consistent with the Core technology category. The asset was fully amortized as of 2019 and 2018, and consisted of gross asset of $51,996 and accumulated amortization of $51,996.
Amortization Expense on Definite-Lived Intangible Assets	The following table presents the amortization expense of the Company’s definite-lived purchased intangible assets, included in each financial statement caption reported in the consolidated statements of income: Year Ended September 30, 2019 2018 2017 Cost of revenue $ 180 $ 572 $ 1,405 Amortization of definite-lived purchased intangible assets 94,205 105,213 108,453 Total $ 94,385 $ 105,785 $ 109,858
Estimated Future Amortization Expense	The estimated future amortization expense of definite-lived purchased intangible assets as of September 30, 2019 is as follows: Amount Fiscal year: 2020 $ 70,138 2021 47,114 2022 34,940 2023 18,904 2024 11,186 Thereafter 22,880 Total $ 205,162

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Provision (benefit) for Income Taxes	The provision (benefit) for income taxes consists of the following: Year Ended September 30, 2019 2018 2017 Current $ 102,391 $ 42,047 $ 69,535 Deferred (13,950 ) 25,098 6,551 Income taxes $ 88,441 $ 67,145 $ 76,086
Components of Deferred Tax Assets and Liabilities	Deferred income taxes are comprised of the following components: As of September 30, 2019 2018 Deferred tax assets: Deferred revenue $ 30,659 $ 30,596 Employee compensation and benefits 76,327 72,218 Intangible assets, computer software and intellectual property 11,805 9,793 Tax credits, net capital and operating loss carryforwards 153,062 184,450 Other 73,249 49,732 Total deferred tax assets 345,102 346,789 Valuation allowances (85,533 ) (112,727 ) Total deferred tax assets, net 259,569 234,062 Deferred tax liabilities: Anticipated withholdings on subsidiaries’ earnings (70,961 ) (68,394 ) Intangible assets, computer software and intellectual property (104,926 ) (114,094 ) Other (81,736 ) (31,750 ) Total deferred tax liabilities (257,623 ) (214,238 ) Net deferred tax assets $ 1,946 $ 19,824
Effective Income Tax Rate Varied from Statutory Guernsey Tax Rate	The effective income tax rate varied from the statutory Guernsey tax rate as follows: Year Ended September 30, 2019 2018 2017 Statutory Guernsey tax rate 0 % 0 % 0 % Foreign taxes(1) 15.6 15.9 14.8 Effective income tax rate 15.6 % 15.9 % 14.8 % As a Guernsey company subject to a corporate tax rate of zero percent, the Company’s overall effective tax rate is attributable to foreign taxes. The Company’s income before income tax expense is considered to be foreign income. (1) Foreign taxes for the year ended Sep 30, 2019: In fiscal year 2019, foreign taxes included a benefit of $26,529 that was primarily attributable to the expiration of the periods set forth in statutes of limitations and to a lesser extent from the conclusions of tax audits related to unrecognized tax benefits accumulated over several years in certain jurisdictions. Foreign taxes in fiscal year 2019 also included a benefit of $12,650 resulting from the release of valuation allowances on deferred tax assets at certain of the Company’s subsidiaries, which will, more likely than not, be realized due to the Company’s projections of future taxable income.
Aggregate Changes in Balance of Company's Gross Unrecognized Tax Benefits	The aggregate changes in the balance of the Company’s gross unrecognized tax benefits were as follows: Year Ended September 30, 2019 2018 2017 Balance at beginning of fiscal year $ 187,646 $ 193,024 $ 196,668 Additions based on tax positions related to the current year 19,530 20,329 22,319 Additions (reduction) for tax positions of prior years 24,980 (3,805 ) 12,261 Settlements with tax authorities(1) (37,672 ) (3,880 ) (9,450 ) Lapse of statute of limitations (25,162 ) (18,022 ) (28,774 ) Balance at end of fiscal year $ 169,322 $ 187,646 $ 193,024 (1) The changes in the year ended September 30, 2019, in the balance of the Company’s gross unrecognized tax benefits that relate to settlements with tax authorities is $37,672, the vast majority of which was offset by income tax payments and increase in Tax Payables and Deferred Tax Liabilities.

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Sep. 30, 2019
Text Block [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following: As of September 30, 2019 2018 Ongoing accrued expenses $ 259,661 $ 256,012 Project-related provisions 140,701 155,739 Taxes payable 28,335 27,843 Dividends payable(1) 38,413 35,046 Derivative instruments(2) 5,053 20,821 Other 175,494 211,176 $ 647,657 $ 706,637 (1) The amounts payable as a result of the August 7, 2019 and the July 31, 2018 dividend declarations. See Note 19 to the consolidated financial statements. (2) Includes derivatives that are designated as hedging instruments and derivatives that are not designated as hedging instruments. See Note 7 to the consolidated financial statements.

Interest and other expense, n_2

Interest and other expense, net (Tables)	12 Months Ended
	Sep. 30, 2019
Other Income and Expenses [Abstract]
Interest and Other Expense, Net	Interest and other expense, net, consists of the following: Year Ended September 30, 2019 2018 2017 Interest income $ 6,225 $ 6,602 $ 7,972 Interest expense (3,911 ) (2,764 ) (1,600 ) Foreign exchange loss (7,860 ) (6,173 ) (8,246 ) Other, net 3,687 (4,431 ) (2,547 ) $ (1,859 ) $ (6,766 ) $ (4,421 )

Contingencies and Commitments (

Contingencies and Commitments (Tables)	12 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Non-Cancelable Lease Payments	Future minimum non-cancelable For the year ended September 30, 2020 $ 69,043 2021 60,544 2022 51,863 2023 31,951 2024 24,350 Thereafter 93,845 $ 331,596

Stock Option and Incentive Pl_2

Stock Option and Incentive Plan (Tables)	12 Months Ended
	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Option Activity	The following table summarizes information about options to purchase the Company ’ Number of Weighted Average Outstanding as of October 1, 2018 6,418 $ 54.76 Granted 1,975 60.04 Exercised (874 ) 47.41 Forfeited (682 ) 60.52 Outstanding as of September 30, 2019(1) 6,837 $ 56.65 Exercisable as of September 30, 2019(1) 2,899 $ 50.60 (1) As of September 30, 2019, the weighted average remaining contractual life of outstanding and exercisable options was 7.24 and 5.63 years, respectively.
Summary of Restricted Shares Activity	The following table summarizes information relating to awards of restricted shares, as well as changes during the fiscal year ended September 30, 2019: Number of Weighted Average Outstanding as of October 1, 2018 1,022 $ 60.68 Granted 521 61.65 Vested (459 ) 59.32 Forfeited (147 ) 61.86 Outstanding as of September 30, 2019 937 $ 61.70
Employee Equity-Based Compensation Pre-Tax Expense	Employee equity-based compensation pre-tax Year Ended September 30, 2019 2018 2017 Cost of revenue $ 19,879 $ 18,253 $ 19,215 Research and development 2,714 3,476 3,536 Selling, general and administrative 15,957 25,747 21,788 Total $ 38,550 $ 47,476 $ 44,539
Assumptions Used in Calculating Fair Value of Options	The fair value of options granted was estimated on the date of grant using the Black-Scholes pricing model with the assumptions noted in the following table (all in weighted averages for options granted during the year): Year Ended September 30, 2019 2018 2017 Risk-free interest rate(1) 2.64 % 2.30 % 1.63 % Expected life of stock options(2) 4.50 4.50 4.50 Expected volatility(3) 17.8 % 15.0 % 16.2 % Expected dividend yield(4) 1.82 % 1.51 % 1.47 % Fair value per option $ 9.13 $ 8.70 $ 7.62 (1) Risk-free interest rate is based upon U.S. Treasury yield curve appropriate for the term of the Company’s employee stock options. (2) Expected life of stock options is based upon historical experience. (3) Expected volatility is based on blended volatility. (4) Expected dividend yield is based on the Company’s history and future expectation of dividend payouts.

Dividends (Tables)

Dividends (Tables)	12 Months Ended
	Sep. 30, 2019
Other Liabilities Disclosure [Abstract]
Summary of Dividends Declared by Board of directors	The Company’s Board of Directors declared the following dividends during the fiscal years ended September 30, 2019, 2018 and 2017: Declaration Date Dividends Per Record Date Total Amount Payment Date August 7, 2019 $ 0.285 September 30, 2019 $ 38,413 October 25, 2019 May 14, 2019 $ 0.285 June 28, 2019 $ 38,730 July 19, 2019 February 5, 2019 $ 0.285 March 29, 2019 $ 39,084 April 19, 2019 November 8, 2018 $ 0.250 December 31, 2018 $ 34,755 January 18, 2019 July 31, 2018 $ 0.250 September 28, 2018 $ 35,046 October 19, 2018 May 10, 2018 $ 0.250 June 29, 2018 $ 35,363 July 20, 2018 January 30, 2018 $ 0.250 March 30, 2018 $ 35,637 April 20, 2018 November 8, 2017 $ 0.220 December 29, 2017 $ 31,556 January 19, 2018 August 2, 2017 $ 0.220 September 29, 2017 $ 31,736 October 23, 2017 May 9, 2017 $ 0.220 June 30, 2017 $ 31,981 July 14, 2017 February 1, 2017 $ 0.220 March 31, 2017 $ 32,223 April 14, 2017 November 8, 2016 $ 0.195 December 30, 2016 $ 28,606 January 13, 2017

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share: Year Ended September 30, 2019 2018 2017 Numerator: Net income $ 479,446 $ 354,396 $ 436,826 Net income and dividends attributable to participating restricted shares (3,295 ) (2,650 ) (3,517 ) Numerator for basic earnings per common share $ 476,151 $ 351,746 $ 433,309 Undistributed income allocated to participating restricted shares 2,252 1,617 2,512 Undistributed income reallocated to participating restricted shares (2,240 ) (1,603 ) (2,488 ) Numerator for diluted earnings per common share $ 476,163 $ 351,760 $ 433,333 Denominator: Weighted average number of shares outstanding — basic 137,418 142,422 146,017 Weighted average number of participating restricted shares (944 ) (1,065 ) (1,176 ) Weighted average number of common shares — basic 136,474 141,357 144,841 Effect of dilutive stock options granted 691 1,282 1,414 Weighted average number of common shares — diluted 137,165 142,639 146,255 Basic earnings per common share $ 3.49 $ 2.49 $ 2.99 Diluted earnings per common share $ 3.47 $ 2.47 $ 2.96

Segment Information and Sales_2

Segment Information and Sales to Significant Customers (Tables)	12 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Summary of Revenue by Geographic Area	The following is a summary of revenue and long-lived assets by geographic area. Revenue is attributed to geographic region based on the location of the customers. Year Ended September 30, 2019 2018 2017 Revenue North America (mainly United States) $ 2,582,719 $ 2,550,234 $ 2,546,290 Europe 598,731 572,196 488,932 Rest of the world 905,219 852,407 831,933 Total $ 4,086,669 $ 3,974,837 $ 3,867,155
Summary of Long-Lived Assets by Geographic Area	As of September 30, 2019 2018 Long-lived Assets(1) Europe $ 206,086 $ 187,884 North America 95,876 88,251 Rest of the world: Israel 168,493 161,726 India 36,546 37,239 Others 18,313 21,485 Total $ 525,314 $ 496,585 (1) Property and equipment, net.
Revenue by Nature of Activities	Revenue by nature of activities Year Ended September 30, 2019 2018 2017 Managed services arrangements $ 2,246,279 $ 2,051,589 $ 2,005,382 Others 1,840,390 1,923,248 1,861,773 Total $ 4,086,669 $ 3,974,837 $ 3,867,155

Selected Quarterly Results of_2

Selected Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations	The following are details of the unaudited quarterly results of operations for the three months ended: September 30, June 30, March 31, December 31, 2019 Revenue $ 1,030,253 $ 1,024,704 $ 1,019,657 $ 1,012,055 Operating income 144,154 142,320 150,175 133,097 Net income 122,027 131,448 124,279 101,692 Basic earnings per share 0.90 0.96 0.90 0.73 Diluted earnings per share 0.90 0.96 0.90 0.72 2018 Revenue $ 1,002,588 $ 1,002,198 $ 992,340 $ 977,711 Operating income 68,819 105,518 131,827 122,143 Net income 44,266 91,530 101,727 116,873 Basic earnings per share 0.31 0.64 0.71 0.81 Diluted earnings per share 0.31 0.64 0.70 0.80

Nature of Entity - Additional I

Nature of Entity - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2019Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segment	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Consolidation and Property and Equipment - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2019
Property and Equipment, Net [Line Items]
Property and equipment, Depreciation methods	Straight-line method
Minimum [Member]
Property and Equipment, Net [Line Items]
Estimated useful life of assets	3 years
Maximum [Member]
Property and Equipment, Net [Line Items]
Estimated useful life of assets	10 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Revenue Recognition and Concentrations of Credit Risk - Additional Information (Detail) $ in Thousands	Sep. 30, 2019USD ($)Customer	Oct. 01, 2018USD ($)	Dec. 31, 2017	Sep. 30, 2019USD ($)Customer	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)Customer	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2019USD ($)Customer	Sep. 30, 2018USD ($)Customer	Sep. 30, 2017USD ($)	Oct. 01, 2019USD ($)
Concentration Risk [Line Items]
Number of customers with an account receivable balance of more than 10% of total accounts receivable | Customer	1			1				1				1	1
Allowance for doubtful accounts	$ 36,121	$ 21,211		$ 36,121				$ 21,211				$ 36,121	$ 21,211
Total assets	5,292,826			5,292,826				5,347,815				5,292,826	5,347,815
Total liabilities	1,750,360			1,750,360				1,855,773				1,750,360	1,855,773
Retained earnings	$ 5,012,799			5,012,799				4,673,901				5,012,799	4,673,901
Revenue				$ 1,030,253	$ 1,024,704	$ 1,019,657	$ 1,012,055	$ 1,002,588	$ 1,002,198	$ 992,340	$ 977,711	4,086,669	3,974,837	$ 3,867,155
Cost of revenue												$ 2,653,172	$ 2,595,276	$ 2,507,656
US federal [Member]
Concentration Risk [Line Items]
US federal corporate tax rate	21.00%		35.00%
Accounts Receivable [Member] | Customer [Member]
Concentration Risk [Line Items]
Aggregate account receivable of more than 10% of total accounts receivable												16.00%	19.00%
Accounting Standards Update 2016-16 [Member]
Concentration Risk [Line Items]
Decrease in retained earnings		3,860
Accounting Standards Update 2014-09 [Member]
Concentration Risk [Line Items]
Retained earnings		4,688,195
Accounting Standards Update 2014-09 [Member] | Adjustments due to ASC 606 [Member]
Concentration Risk [Line Items]
Retained earnings		$ 14,294
Revenue												$ 26,096
Cost of revenue												$ (11,051)
Accounting Standards Update 2016-02 [Member] | Scenario, Adjustment [Member] | Minimum [Member]
Concentration Risk [Line Items]
Total assets															$ 260,000
Total liabilities															260,000
Accounting Standards Update 2016-02 [Member] | Scenario, Adjustment [Member] | Maximum [Member]
Concentration Risk [Line Items]
Total assets															310,000
Total liabilities															$ 310,000

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Impact of Adoption of ASC 606 on Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Oct. 01, 2018	Sep. 30, 2018
Account receivable-unbilled	$ 227,061	$ 274,036	$ 263,997
Prepaid expenses and other current assets	216,084		229,999
Other noncurrent assets	423,941		420,369
Deferred revenue (current)	118,182	146,462	132,414
Accrued expenses and other current liabilities	647,657		706,637
Deferred income taxes and taxes payable	207,508		224,572
Retained earnings	$ 5,012,799		$ 4,673,901
Accounting Standards Update 2014-09 [Member]
Account receivable-unbilled		274,036
Prepaid expenses and other current assets		229,028
Other noncurrent assets		436,005
Deferred revenue (current)		146,462
Accrued expenses and other current liabilities		692,575
Deferred income taxes and taxes payable		234,996
Retained earnings		4,688,195
Accounting Standards Update 2014-09 [Member] | Adjustments due to ASC 606 [Member]
Account receivable-unbilled		10,039
Prepaid expenses and other current assets		(971)
Other noncurrent assets		15,636
Deferred revenue (current)		14,048
Accrued expenses and other current liabilities		(14,062)
Deferred income taxes and taxes payable		10,424
Retained earnings		$ 14,294

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) $ in Thousands	12 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)Business
Business Acquisition [Line Items]
Business acquisition		$ 355,142
Number of businesses acquired | Business		3
TTS Wireless [Member]
Business Acquisition [Line Items]
Business acquisition	$ 50,000

Revenue - Summary of Accounts R

Revenue - Summary of Accounts Receivable Billed and Unbilled and Deferred Revenue (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Oct. 01, 2018	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Accounts receivable-billed (net of allowances for doubtful accounts of $21,211 as of September 30 and October 1, 2018 and $36,121 as of September 30, 2019)	$ 760,797	$ 707,505	$ 707,505
Accounts receivable - unbilled (current)	227,061	274,036	263,997
Accounts receivable - unbilled (non-current)	16,987	13,185	15,686
Total Accounts receivable-unbilled	244,048	287,221	279,683
Deferred revenue (current)	(118,182)	(146,462)	(132,414)
Deferred revenue (non-current)	(23,785)	(27,977)	(27,977)
Total Deferred revenue	$ (141,967)	$ (174,439)	$ (160,391)

Revenue - Summary of Accounts_2

Revenue - Summary of Accounts Receivable Billed and Unbilled and Deferred Revenue (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Oct. 01, 2018	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Allowance for doubtful accounts	$ 36,121	$ 21,211	$ 21,211

Revenue - Additional Informatio

Revenue - Additional Information (Detail) $ in Thousands	12 Months Ended
	Sep. 30, 2019USD ($)
Deferred revenue recognized	$ 93,508
Prior period unbilled receivable, billed	129,230
Unsatisfied remaining performance obligations	$ 5,500,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Remaining performance obligation, expected timing of recognized	3 years

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Measurement on Company's Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments	$ 69,370	$ 131,316
Corporate Bonds [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		47,531
Money Market Funds [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments	69,370	30,883
U.S. Government Treasuries [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		23,258
U.S. Agency Securities [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		16,033
Asset Backed Obligations [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		9,177
Supranational and Sovereign Debt [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		4,434
Recurring [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments	69,370	131,316
Equity Investment	18,008
Derivative financial instruments, net	7,890	(27,842)
Other liabilities	(29,805)	(37,954)
Total	65,463	65,520
Recurring [Member] | Corporate Bonds [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		47,531
Recurring [Member] | Money Market Funds [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments	69,370	30,883
Recurring [Member] | U.S. Government Treasuries [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		23,258
Recurring [Member] | U.S. Agency Securities [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		16,033
Recurring [Member] | Asset Backed Obligations [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		9,177
Recurring [Member] | Supranational and Sovereign Debt [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		4,434
Level 1 [Member] | Recurring [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments	69,370	54,141
Total	69,370	54,141
Level 1 [Member] | Recurring [Member] | Money Market Funds [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments	69,370	30,883
Level 1 [Member] | Recurring [Member] | U.S. Government Treasuries [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		23,258
Level 2 [Member] | Recurring [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		77,175
Derivative financial instruments, net	7,890	(27,842)
Total	7,890	49,333
Level 2 [Member] | Recurring [Member] | Corporate Bonds [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		47,531
Level 2 [Member] | Recurring [Member] | U.S. Agency Securities [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		16,033
Level 2 [Member] | Recurring [Member] | Asset Backed Obligations [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		9,177
Level 2 [Member] | Recurring [Member] | Supranational and Sovereign Debt [Member]
Available-for-sale securities:
Fair value, Measured on recurring basis, Investments		4,434
Level 3 [Member] | Recurring [Member]
Available-for-sale securities:
Equity Investment	18,008
Other liabilities	(29,805)	(37,954)
Total	$ (11,797)	$ (37,954)

Available-for-Sale Securities -

Available-for-Sale Securities - Additional Information (Detail) $ in Thousands	12 Months Ended
	Sep. 30, 2019USD ($)
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities	$ 101,287

Available-for-Sale Securities_2

Available-for-Sale Securities - Interest-bearing Investments in Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 69,370	$ 132,908
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	1,592
Fair Value	69,370	131,316
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		48,252
Gross Unrealized Gains		0
Gross Unrealized Losses		721
Fair Value		47,531
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	69,370	30,883
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 69,370	30,883
U.S. Government Treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		23,656
Gross Unrealized Gains		0
Gross Unrealized Losses		398
Fair Value		23,258
U.S. Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		16,297
Gross Unrealized Gains		0
Gross Unrealized Losses		264
Fair Value		16,033
Asset Backed Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		9,312
Gross Unrealized Gains		0
Gross Unrealized Losses		135
Fair Value		9,177
Supranational and Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		4,508
Gross Unrealized Gains		0
Gross Unrealized Losses		74
Fair Value		$ 4,434

Available-for-Sale Securities_3

Available-for-Sale Securities - Interest-bearing Investments in Available-for-Sale Securities (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	$ 69,370	$ 131,316
Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of short term interest-bearing securities included in cash and cash equivalents	Longer than 90 days	Longer than 90 days
Available-for-sale securities		$ 100,433
Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of short term interest-bearing securities included in cash and cash equivalents	90 days or less	90 days or less
Available-for-sale securities	$ 69,370	$ 30,883

Available-for-Sale Securities_4

Available-for-Sale Securities - Available-for-Sale Securities Debt Maturities Market Value (Detail) $ in Thousands	Sep. 30, 2019USD ($)
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Due within one year	$ 69,370

Derivative Financial Instrume_3

Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, (Loss) Gain [Line Items]
Maximum amount of loss due to credit risk	$ 11,373
Maximum length of time hedged in cash flow hedges	3 years
Maximum maturity period of significant portion of forward and option contracts outstanding	12 months
Net unrealized gain (loss) from cash flow hedges recognized in other comprehensive income (loss) , net of taxes	$ 19,228	$ (31,908)	$ 36,765
Typical maturity period of other risk management derivatives	Less than 12 months
Foreign Exchange Contracts [Member]
Derivative Instruments, (Loss) Gain [Line Items]
Net unrealized gain (loss) from cash flow hedges recognized in other comprehensive income (loss)	$ 20,035	(34,260)	39,692
Net unrealized gain (loss) from cash flow hedges recognized in other comprehensive income (loss) , net of taxes	19,228	$ (31,908)	$ 36,765
Foreign currency cash flow hedge, reclassified into earnings during fiscal year 2020	$ 5,085

Derivative Financial Instrume_4

Derivative Financial Instruments - Notional Amounts of Derivative Instruments (Detail) $ in Thousands	Sep. 30, 2019USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Foreign exchange contracts	$ 1,103,169

Derivative Financial Instrume_5

Derivative Financial Instruments - Fair Value of Open Foreign Currency Exchange Contracts (Detail) - Foreign Exchange Contracts [Member] - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Derivatives, Fair Value [Line Items]
Net fair value	$ 7,890	$ (27,842)
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Net fair value	4,880	(27,465)
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Net fair value	3,010	(377)
Prepaid Expenses and Other Current Assets [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	9,344	221
Prepaid Expenses and Other Current Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	5,086	2,758
Other Noncurrent Assets [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	585	25
Accrued Expenses and Other Current Liabilities [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	(2,977)	(17,681)
Accrued Expenses and Other Current Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	(2,076)	(3,135)
Other Noncurrent Liabilities [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	$ (2,072)	$ (10,030)

Derivative Financial Instrume_6

Derivative Financial Instruments - Effect of Cash Flow Hedging Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, (Loss) Gain [Line Items]
(Losses) Gains Reclassified from Other Comprehensive Income (Loss) (Effective Portion)	$ (12,976)	$ 21,337	$ 28,349
Revenue [Member]
Derivative Instruments, (Loss) Gain [Line Items]
(Losses) Gains Reclassified from Other Comprehensive Income (Loss) (Effective Portion)	19	(1,129)	(1,021)
Cost of Revenue [Member]
Derivative Instruments, (Loss) Gain [Line Items]
(Losses) Gains Reclassified from Other Comprehensive Income (Loss) (Effective Portion)	(8,627)	15,877	21,783
Research and Development [Member]
Derivative Instruments, (Loss) Gain [Line Items]
(Losses) Gains Reclassified from Other Comprehensive Income (Loss) (Effective Portion)	(2,059)	3,127	4,282
Selling, General and Administrative [Member]
Derivative Instruments, (Loss) Gain [Line Items]
(Losses) Gains Reclassified from Other Comprehensive Income (Loss) (Effective Portion)	$ (2,309)	$ 3,462	$ 3,305

Derivative Financial Instrume_7

Derivative Financial Instruments - Changes in Net Unrealized Gains (Losses) on Cash Flow Hedges (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net unrealized (loss) gain on cash flow hedges, net of tax, beginning of period	$ (26,608)	$ 24,508	$ 12,514
Changes in fair value of cash flow hedges, net of tax	19,228	(31,908)	36,765
Reclassification of loss (gain) into earnings, net of tax	11,325	(19,208)	(24,771)
Net unrealized gain (loss) on cash flow hedges, net of tax, end of period	$ 3,945	$ (26,608)	$ 24,508

Derivative Financial Instrume_8

Derivative Financial Instruments - Effect of Non-Designated as Hedging Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, (Loss) Gain [Line Items]
Gains (losses) Recognized in Income	$ 6,026	$ 2,356	$ (4,848)
Cost of Revenue [Member]
Derivative Instruments, (Loss) Gain [Line Items]
Gains (losses) Recognized in Income	401	(4,577)	4,639
Research and Development [Member]
Derivative Instruments, (Loss) Gain [Line Items]
Gains (losses) Recognized in Income	14	(736)	957
Selling, General and Administrative [Member]
Derivative Instruments, (Loss) Gain [Line Items]
Gains (losses) Recognized in Income	294	(950)	1,723
Interest and Other Income (Expense), Net [Member]
Derivative Instruments, (Loss) Gain [Line Items]
Gains (losses) Recognized in Income	5,845	7,038	(10,514)
Income Taxes [Member]
Derivative Instruments, (Loss) Gain [Line Items]
Gains (losses) Recognized in Income	$ (528)	$ 1,581	$ (1,653)

Property and Equipment, Net - C

Property and Equipment, Net - Components of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Property and Equipment, Net [Line Items]
Property and equipment, gross	$ 1,497,541	$ 1,391,937
Less accumulated depreciation	(972,227)	(895,352)
Property and equipment, net	525,314	496,585
Computers, Related Equipment and Software [Member]
Property and Equipment, Net [Line Items]
Property and equipment, gross	1,109,465	1,027,825
Building and Land [Member]
Property and Equipment, Net [Line Items]
Property and equipment, gross	109,446	97,782
Leasehold Improvements [Member]
Property and Equipment, Net [Line Items]
Property and equipment, gross	230,817	222,812
Furniture, Fixtures and Other [Member]
Property and Equipment, Net [Line Items]
Property and equipment, gross	$ 47,813	$ 43,518

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Property and Equipment [Abstract]
Depreciation expense	$ 111,387	$ 105,439	$ 105,027
Software assets developed for internal use costs, net of accumulated depreciation	$ 171,331	$ 152,366

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets, Net - Details of Total Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Beginning Balance	$ 2,444,895	$ 2,221,209
Goodwill resulting from acquisitions	17,484	227,283
Other	456	(3,597)
Goodwill, Ending Balance	$ 2,462,835	$ 2,444,895

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets, Net - Details of Total Goodwill (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Goodwill [Line Items]
Goodwill resulting from acquisitions	$ 17,484	$ 227,283
Value of intangible asset	205,162	265,249
Core Technology [Member]
Goodwill [Line Items]
Value of intangible asset	84,518	144,448
Customer Relationships [Member]
Goodwill [Line Items]
Value of intangible asset	111,242	110,519
TTS Wireless [Member]
Goodwill [Line Items]
Goodwill resulting from acquisitions	10,032
TTS Wireless [Member] | Trademarks [Member]
Goodwill [Line Items]
Value of intangible asset	$ 1,300
Useful life of intangible assets	4 years
TTS Wireless [Member] | Core Technology [Member]
Goodwill [Line Items]
Value of intangible asset	$ 2,100
Useful life of intangible assets	6 years
TTS Wireless [Member] | Customer Relationships [Member]
Goodwill [Line Items]
Value of intangible asset	$ 29,500
Useful life of intangible assets	6 years
Vubiquity [Member]
Goodwill [Line Items]
Goodwill resulting from acquisitions		148,184
Vubiquity [Member] | Trademarks [Member]
Goodwill [Line Items]
Value of intangible asset		$ 10,104
Useful life of intangible assets		8 years
Vubiquity [Member] | Core Technology [Member]
Goodwill [Line Items]
Value of intangible asset		$ 45,692
Useful life of intangible assets		5 years
Vubiquity [Member] | Customer Relationships [Member]
Goodwill [Line Items]
Value of intangible asset		$ 38,630
Useful life of intangible assets		9 years
Projekt 202 [Member]
Goodwill [Line Items]
Goodwill resulting from acquisitions		$ 34,390
Projekt 202 [Member] | Customer Relationships [Member]
Goodwill [Line Items]
Value of intangible asset		$ 19,835
Useful life of intangible assets		4 years
UXP Systems [Member]
Goodwill [Line Items]
Goodwill resulting from acquisitions		$ 40,629
UXP Systems [Member] | Core Technology [Member]
Goodwill [Line Items]
Value of intangible asset		$ 31,552
Useful life of intangible assets		5 years
UXP Systems [Member] | Customer Relationships [Member]
Goodwill [Line Items]
Value of intangible asset		$ 6,552
Useful life of intangible assets		5 years

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets, Net - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2019USD ($)Segment	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment of goodwill | $	$ 0	$ 0	$ 0
Number of operating segment | Segment	1

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets, Net - Details Regarding Total Definite-Lived Purchased Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Gross	$ 1,414,980	$ 1,380,682
Accumulated Amortization	(1,209,818)	(1,115,433)
Total	205,162	265,249
Core Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	775,479	773,380
Accumulated Amortization	(690,961)	(628,932)
Total	84,518	144,448
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	594,555	563,656
Accumulated Amortization	(483,313)	(453,137)
Total	111,242	110,519
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	44,946	43,646
Accumulated Amortization	(35,544)	(33,364)
Total	$ 9,402	$ 10,282

Goodwill and Intangible Asset_7

Goodwill and Intangible Assets, Net - Details Regarding Total Definite-Lived Purchased Intangible Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Gross asset	$ 1,414,980	$ 1,380,682
Accumulated amortization	1,209,818	1,115,433
Intellectual Property Rights and Purchased Computer Software [Member]
Finite-Lived Intangible Assets [Line Items]
Gross asset	51,996	51,996
Accumulated amortization	$ 51,996	$ 51,996

Goodwill and Intangible Asset_8

Goodwill and Intangible Assets, Net - Amortization Expense on Definite-Lived Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Cost of revenue	$ 180	$ 572	$ 1,405
Amortization of definite-lived purchased intangible assets	94,205	105,213	108,453
Total	$ 94,385	$ 105,785	$ 109,858

Goodwill and Intangible Asset_9

Goodwill and Intangible Assets, Net - Estimated Future Amortization Expense (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 70,138
2021	47,114
2022	34,940
2023	18,904
2024	11,186
Thereafter	22,880
Total	$ 205,162	$ 265,249

Non-recurring charges - Additio

Non-recurring charges - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Employee Severance [Member]
Schedule of Non-recurring Charges [Line Items]
Restructuring charge		$ 30,057
Long Running Legal Dispute [Member]
Schedule of Non-recurring Charges [Line Items]
Non-recurring charges		$ 55,000
Settlement payments	$ 50,000
Legal fees and other associated costs	$ 5,000

Income Taxes - Provision (Benef

Income Taxes - Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Current	$ 102,391	$ 42,047	$ 69,535
Deferred	(13,950)	25,098	6,551
Income taxes	$ 88,441	$ 67,145	$ 76,086

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Taxes [Line Items]
Net increase (decrease) in valuation allowances	$ (27,194)	$ 18,154
Tax credits, net capital and operating loss carryforwards	797,091	894,997
Tax credits, net capital and operating loss carryforwards having expiration date	$ 244,711	$ 322,816
Tax credits, net capital and operating loss carryforwards expiration date	Through 2039 for $244,711 in net operating losses	Through 2038 for $322,816 in net operating losses
Gross unrecognized tax benefits	$ 169,322	$ 187,646	$ 193,024	$ 196,668
Accrued income taxes payable for interest and penalties relating to unrecognized tax benefits	31,108	30,807
Accrued income taxes payable for interest and penalties relating to unrecognized tax benefits, tax expense (benefit) recognized in the statements of income, net of interest and penalty reversals	4,679	$ 2,579
Maximum [Member]
Income Taxes [Line Items]
Expected decrease in unrecognized tax benefits within next 12 months	$ 12,763
GUERNSEY
Income Taxes [Line Items]
Statutory Guernsey tax rate	0.00%	0.00%	0.00%
Prepaid Expenses and Other Current Assets [Member]
Income Taxes [Line Items]
Tax receivable balance	$ 53,143	$ 55,198

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Deferred tax assets:
Deferred revenue	$ 30,659	$ 30,596
Employee compensation and benefits	76,327	72,218
Intangible assets, computer software and intellectual property	11,805	9,793
Tax credits, net capital and operating loss carryforwards	153,062	184,450
Other	73,249	49,732
Total deferred tax assets	345,102	346,789
Valuation allowances	(85,533)	(112,727)
Total deferred tax assets, net	259,569	234,062
Deferred tax liabilities:
Anticipated withholdings on subsidiaries' earnings	(70,961)	(68,394)
Intangible assets, computer software and intellectual property	(104,926)	(114,094)
Other	(81,736)	(31,750)
Total deferred tax liabilities	(257,623)	(214,238)
Net deferred tax assets	$ 1,946	$ 19,824

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Varied from Statutory Guernsey Tax Rate (Detail)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Schedule of Effective Income Tax Rate Reconciliation [Line Items]
Foreign taxes (percentage)	15.60%	15.90%	14.80%
Effective income tax rate	15.60%	15.90%	14.80%
GUERNSEY
Schedule of Effective Income Tax Rate Reconciliation [Line Items]
Statutory Guernsey tax rate	0.00%	0.00%	0.00%

Income Taxes - Effective Inco_2

Income Taxes - Effective Income Tax Rate Varied from Statutory Guernsey Tax Rate (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Lapse of statute of limitations	$ 25,162	$ 18,022	$ 28,774
Tax benefit from release of gross unrecognized tax benefits	26,529	9,564
Net (benefit) provisional expense from release of valuation allowances on deferred tax assets	$ (12,650)	12,032
Provisional expense due to US tax law change		2,321
Provisional tax liability related to tax implications of retaining earnings		4,059
Tax benefit related to the release of withholding and income tax reserves for unremitting earnings		$ 28,795

Income Taxes - Aggregate Change

Income Taxes - Aggregate Changes in Balance of Company's Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, Beginning balance	$ 187,646	$ 193,024	$ 196,668
Additions based on tax positions related to the current year	19,530	20,329	22,319
Additions for tax positions of prior years	24,980		12,261
Reduction for tax positions of prior years		(3,805)
Settlements with tax authorities	(37,672)	(3,880)	(9,450)
Lapse of statute of limitations	(25,162)	(18,022)	(28,774)
Unrecognized tax benefits, Ending balance	$ 169,322	$ 187,646	$ 193,024

Income Taxes - Aggregate Chan_2

Income Taxes - Aggregate Changes in Balance of Company's Gross Unrecognized Tax Benefits (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Settlements with tax authorities	$ 37,672	$ 3,880	$ 9,450

Repurchase of Shares - Addition

Repurchase of Shares - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Sep. 30, 2019	Nov. 12, 2019	Nov. 08, 2017
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, Authorized amount		$ 800,000,000
Repurchase of shares, Shares	6,656
Average price at which ordinary shares are repurchased	$ 59.79
Remaining authority to repurchase outstanding ordinary shares	$ 1,039,171,000
Share Repurchase Program 2017 Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, Authorized amount			$ 800,000,000

Financing Arrangements - Additi

Financing Arrangements - Additional Information (Detail) - USD ($)	1 Months Ended					12 Months Ended
	Apr. 30, 2018	Dec. 31, 2017	Apr. 30, 2017	Dec. 31, 2014	Dec. 31, 2011	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2019	Mar. 31, 2018	Mar. 31, 2017
Line of Credit Facility [Line Items]
Payments under financing arrangements						$ 120,000,000	$ 400,000,000
Outstanding letters of credit and bank guarantees								$ 91,291,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Five-year revolving credit facility					$ 500,000,000
Revolving credit facility, maturity term					5 years
Revolving credit facility, maturity period		2022-12		2019-12
Borrowings under the revolving credit facility									$ 120,000,000	$ 200,000,000
Payments under financing arrangements	$ 120,000,000		$ 200,000,000
Outstanding borrowings								$ 0

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Payables and Accruals [Abstract]
Ongoing accrued expenses	$ 259,661	$ 256,012
Project-related provisions	140,701	155,739
Taxes payable	28,335	27,843
Dividends payable	38,413	35,046
Derivative instruments	5,053	20,821
Other	175,494	211,176
Total accrued expenses and other current liabilities	$ 647,657	$ 706,637

Interest and Other Expense, N_3

Interest and Other Expense, Net - Interest and Other Expense, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Other Income and Expenses [Abstract]
Interest income	$ 6,225	$ 6,602	$ 7,972
Interest expense	(3,911)	(2,764)	(1,600)
Foreign exchange loss	(7,860)	(6,173)	(8,246)
Other, net	3,687	(4,431)	(2,547)
Total	$ (1,859)	$ (6,766)	$ (4,421)

Contingencies and Commitments -

Contingencies and Commitments - Future Minimum Non-Cancelable Lease Payments (Detail) - Office Space [Member] $ in Thousands	Sep. 30, 2019USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2020	$ 69,043
2021	60,544
2022	51,863
2023	31,951
2024	24,350
Thereafter	93,845
Total	$ 331,596

Contingencies and Commitments_2

Contingencies and Commitments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Commitments and Contingencies Disclosure [Line Items]
Rent expense, net of sublease income	$ 65,692	$ 63,603	$ 55,480
Long Running Legal Dispute [Member]
Commitments and Contingencies Disclosure [Line Items]
Settlement payments	50,000
Legal fees and other costs	$ 5,000

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Retirement Benefits [Abstract]
Severance pay liability	$ 266,209	$ 258,262
Deposit with insurance companies	206,752	202,230
Severance expenses	$ 33,355	$ 28,472	$ 32,908

Stock Option and Incentive Pl_3

Stock Option and Incentive Plan - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized to be granted	67,550,000			67,550,000	62,300,000
Stock option awards, term	10 years			10 years
Total intrinsic value of options exercised		$ 13,081	$ 38,025	$ 47,321
Value of restricted shares vested		28,430	$ 35,801	$ 36,922
Aggregate intrinsic value of stock options outstanding		56,997
Aggregate intrinsic value of stock options exercisable		$ 40,532
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option awards, vesting period	3 years			3 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option awards, vesting period	4 years			4 years

Stock Option and Incentive Pl_4

Stock Option and Incentive Plan - Summary of Option Activity (Detail) shares in Thousands	12 Months Ended
	Sep. 30, 2019$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Share Options, Outstanding, Beginning Balance | shares	6,418
Number of Share Options, Granted | shares	1,975
Number of Share Options, Exercised | shares	(874)
Number of Share Options, Forfeited | shares	(682)
Number of Share Options, Outstanding, Ending Balance | shares	6,837
Number of Share Options, Exercisable | shares	2,899
Weighted Average Exercise Price, Outstanding, Beginning Balance | $ / shares	$ 54.76
Weighted Average Exercise Price, Granted | $ / shares	60.04
Weighted Average Exercise Price, Exercised | $ / shares	47.41
Weighted Average Exercise Price, Forfeited | $ / shares	60.52
Weighted Average Exercise Price, Outstanding, Ending Balance | $ / shares	56.65
Weighted Average Exercise Price, Exercisable | $ / shares	$ 50.60

Stock Option and Incentive Pl_5

Stock Option and Incentive Plan - Summary of Option Activity (Parenthetical) (Detail)	12 Months Ended
	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted average remaining contractual life of outstanding options	7 years 2 months 26 days
Weighted average remaining contractual life of exercisable options	5 years 7 months 17 days

Stock Option and Incentive Pl_6

Stock Option and Incentive Plan - Summary of Restricted Shares Activity (Detail) shares in Thousands	12 Months Ended
	Sep. 30, 2019$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Restricted Shares, Outstanding, Beginning Balance | shares	1,022
Number of Restricted Shares, Granted | shares	521
Number of Restricted Shares, Vested | shares	(459)
Number of Restricted Shares, Forfeited | shares	(147)
Number of Restricted Shares, Ending Balance | shares	937
Restricted Shares, Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 60.68
Restricted Shares, Weighted Average Grant Date Fair Value, Granted | $ / shares	61.65
Restricted Shares, Weighted Average Grant Date Fair Value, Vested | $ / shares	59.32
Restricted Shares, Weighted Average Grant Date Fair Value, Forfeited | $ / shares	61.86
Restricted Shares, Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 61.70

Stock Option and Incentive Pl_7

Stock Option and Incentive Plan - Employee Equity-Based Compensation Pre-Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation pre-tax expense	$ 38,550	$ 47,476	$ 44,539
Cost of Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation pre-tax expense	19,879	18,253	19,215
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation pre-tax expense	2,714	3,476	3,536
Selling, General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation pre-tax expense	$ 15,957	$ 25,747	$ 21,788

Stock Option and Incentive Pl_8

Stock Option and Incentive Plan - Assumptions Used in Calculating Fair Value of Options (Detail) - $ / shares	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk-free interest rate	2.64%	2.30%	1.63%
Expected life of stock options	4 years 6 months	4 years 6 months	4 years 6 months
Expected volatility	17.80%	15.00%	16.20%
Expected dividend yield	1.82%	1.51%	1.47%
Fair value per option	$ 9.13	$ 8.70	$ 7.62

Dividends - Summary of Dividend

Dividends - Summary of Dividends Declared by Board of directors (Detail) - USD ($) $ / shares in Units, $ in Thousands

Aug. 07, 2019

May 14, 2019

Feb. 05, 2019

Nov. 08, 2018

Jul. 31, 2018

May 10, 2018

Jan. 30, 2018

Nov. 08, 2017

Aug. 02, 2017

May 09, 2017

Feb. 01, 2017

Nov. 08, 2016

Sep. 30, 2019

Sep. 30, 2018

Sep. 30, 2017

Dividends Payable [Line Items]

Dividends Per Ordinary Share

$ 1.105

$ 0.970

$ 0.855

Declaration Date, August 7, 2018 [Member]

Dividends Payable [Line Items]

Declaration Date

Aug. 7, 2019

Record Date

Sep. 30, 2019

Payment Date

Oct. 25, 2019

Dividends Per Ordinary Share

$ 0.285

Total Amount

$ 38,413

Declaration Date, May 14, 2019 [Member]

Dividends Payable [Line Items]

Declaration Date

May 14, 2019

Record Date

Jun. 28, 2019

Payment Date

Jul. 19, 2019

Dividends Per Ordinary Share

$ 0.285

Total Amount

$ 38,730

Declaration Date, February 5, 2019 [Member]

Dividends Payable [Line Items]

Declaration Date

Feb. 5, 2019

Record Date

Mar. 29, 2019

Payment Date

Apr. 19, 2019

Dividends Per Ordinary Share

$ 0.285

Total Amount

$ 39,084

Declaration Date, November 8, 2017 [Member]

Dividends Payable [Line Items]

Declaration Date

Nov. 8, 2017

Record Date

Dec. 29, 2017

Payment Date

Jan. 19, 2018

Dividends Per Ordinary Share

$ 0.220

Total Amount

$ 31,556

Declaration Date, July 31, 2018 [Member]

Dividends Payable [Line Items]

Declaration Date

Jul. 31, 2018

Record Date

Sep. 28, 2018

Payment Date

Oct. 19, 2018

Dividends Per Ordinary Share

$ 0.250

Total Amount

$ 35,046

Declaration Date, May 10, 2018 [Member]

Dividends Payable [Line Items]

Declaration Date

May 10, 2018

Record Date

Jun. 29, 2018

Payment Date

Jul. 20, 2018

Dividends Per Ordinary Share

$ 0.250

Total Amount

$ 35,363

Declaration Date, January 30, 2018 [Member]

Dividends Payable [Line Items]

Declaration Date

Jan. 30, 2018

Record Date

Mar. 30, 2018

Payment Date

Apr. 20, 2018

Dividends Per Ordinary Share

$ 0.250

Total Amount

$ 35,637

Declaration Date, November 8, 2018 [Member]

Dividends Payable [Line Items]

Declaration Date

Nov. 8, 2018

Record Date

Dec. 31, 2018

Payment Date

Jan. 18, 2019

Dividends Per Ordinary Share

$ 0.250

Total Amount

$ 34,755

Declaration Date, August 2, 2017 [Member]

Dividends Payable [Line Items]

Declaration Date

Aug. 2, 2017

Record Date

Sep. 29, 2017

Payment Date

Oct. 23, 2017

Dividends Per Ordinary Share

$ 0.220

Total Amount

$ 31,736

Declaration Date, May 9, 2017 [Member]

Dividends Payable [Line Items]

Declaration Date

May 9, 2017

Record Date

Jun. 30, 2017

Payment Date

Jul. 14, 2017

Dividends Per Ordinary Share

$ 0.220

Total Amount

$ 31,981

Declaration Date, February 1, 2017 [Member]

Dividends Payable [Line Items]

Declaration Date

Feb. 1, 2017

Record Date

Mar. 31, 2017

Payment Date

Apr. 14, 2017

Dividends Per Ordinary Share

$ 0.220

Total Amount

$ 32,223

Declaration Date, November 8, 2016 [Member]

Dividends Payable [Line Items]

Declaration Date

Nov. 8, 2016

Record Date

Dec. 30, 2016

Payment Date

Jan. 13, 2017

Dividends Per Ordinary Share

$ 0.195

Total Amount

$ 28,606

Dividends - Additional Informat

Dividends - Additional Information (Detail)	Nov. 12, 2019$ / shares
Dividends Payable [Line Items]
Quarterly dividend payment per share	$ 0.3275
Cash dividend anticipated payable date	2020-04
First Installment [Member]
Dividends Payable [Line Items]
Dividends payable date declared	Nov. 12, 2019
Quarterly dividend payment per share	$ 0.285
Record Date	Dec. 31, 2019
Cash dividend payable date	Jan. 24, 2020

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2017
Numerator
Net income	$ 122,027	$ 131,448	$ 124,279	$ 101,692	$ 44,266	$ 91,530	$ 101,727	$ 116,873	$ 479,446	[1]	$ 354,396	[1]	$ 436,826
Net income and dividends attributable to participating restricted shares									(3,295)		(2,650)		(3,517)
Numerator for basic earnings per common share									476,151		351,746		433,309
Undistributed income allocated to participating restricted shares									2,252		1,617		2,512
Undistributed income reallocated to participating restricted shares									(2,240)		(1,603)		(2,488)
Numerator for diluted earnings per common share									$ 476,163		$ 351,760		$ 433,333
Denominator
Weighted average number of shares outstanding - basic									137,418		142,422		146,017
Weighted average number of participating restricted shares									(944)		(1,065)		(1,176)
Weighted average number of common shares - basic									136,474		141,357		144,841
Effect of dilutive stock options granted									691		1,282		1,414
Weighted average number of common shares - diluted									137,165		142,639		146,255
Basic earnings per common share	$ 0.90	$ 0.96	$ 0.90	$ 0.73	$ 0.31	$ 0.64	$ 0.71	$ 0.81	$ 3.49		$ 2.49		$ 2.99
Diluted earnings per common share	$ 0.90	$ 0.96	$ 0.90	$ 0.72	$ 0.31	$ 0.64	$ 0.70	$ 0.80	$ 3.47		$ 2.47		$ 2.96
[1]	In fiscal years 2019 and 2018, all of the Company's net income is attributable to Amdocs Limited as the net income attributable to the Non-controlling interests is negligible.

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares shares in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Weighted average number of shares attributable to antidilutive outstanding stock options not included in the calculation of diluted earnings per share	3,547	1,357	1,281

Segment Information and Sales_3

Segment Information and Sales to Significant Customers - Summary of Revenue by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,030,253	$ 1,024,704	$ 1,019,657	$ 1,012,055	$ 1,002,588	$ 1,002,198	$ 992,340	$ 977,711	$ 4,086,669	$ 3,974,837	$ 3,867,155
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									2,582,719	2,550,234	2,546,290
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									598,731	572,196	488,932
Rest of the World [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									$ 905,219	$ 852,407	$ 831,933

Segment Information and Sales_4

Segment Information and Sales to Significant Customers - Summary of Long-lived Assets by Geographic Area (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	$ 525,314	$ 496,585
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	95,876	88,251
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	206,086	187,884
Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	168,493	161,726
India [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	36,546	37,239
Others [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	$ 18,313	$ 21,485

Segment Information and Sales_5

Segment Information and Sales to Significant Customers - Summary of Revenue by Nature of Activities (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,030,253	$ 1,024,704	$ 1,019,657	$ 1,012,055	$ 1,002,588	$ 1,002,198	$ 992,340	$ 977,711	$ 4,086,669	$ 3,974,837	$ 3,867,155
Managed services program arrangements [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									2,246,279	2,051,589	2,005,382
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									$ 1,840,390	$ 1,923,248	$ 1,861,773

Segment Information and Sales_6

Segment Information and Sales to Significant Customers - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Revenue, Major Customer [Line Items]
Minimum percentage of total revenue accounted for one customer	10.00%	10.00%	10.00%
Revenue [Member] | Customer [Member]
Revenue, Major Customer [Line Items]
Percentage of revenue from significant customer	23.00%	27.00%	33.00%

Selected Quarterly Results of_3

Selected Quarterly Results of Operations - Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 1,030,253	$ 1,024,704	$ 1,019,657	$ 1,012,055	$ 1,002,588	$ 1,002,198	$ 992,340	$ 977,711	$ 4,086,669		$ 3,974,837		$ 3,867,155
Operating income	144,154	142,320	150,175	133,097	68,819	105,518	131,827	122,143	569,746		428,307		517,333
Net income	$ 122,027	$ 131,448	$ 124,279	$ 101,692	$ 44,266	$ 91,530	$ 101,727	$ 116,873	$ 479,446	[1]	$ 354,396	[1]	$ 436,826
Basic earnings per share	$ 0.90	$ 0.96	$ 0.90	$ 0.73	$ 0.31	$ 0.64	$ 0.71	$ 0.81	$ 3.49		$ 2.49		$ 2.99
Diluted earnings per share	$ 0.90	$ 0.96	$ 0.90	$ 0.72	$ 0.31	$ 0.64	$ 0.70	$ 0.80	$ 3.47		$ 2.47		$ 2.96
[1]	In fiscal years 2019 and 2018, all of the Company's net income is attributable to Amdocs Limited as the net income attributable to the Non-controlling interests is negligible.

Schedule - Valuation and Qualif

Schedule - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Accounts Receivable Allowances [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	$ 21,211	$ 28,726	$ 39,512
Charged to costs and expenses	22,260	6,134	17,282
Charged to other accounts	2,406	1,226	1,985
Deductions	(9,756)	(14,875)	(30,053)
Ending Balance	36,121	21,211	28,726
Valuation Allowances on Net Deferred Tax Assets [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	112,727	94,573	96,870
Charged to costs and expenses	1,009	18,173	16,425
Charged to other accounts	6,008	6,121	5,000
Deductions	(34,211)	(6,140)	(23,722)
Ending Balance	$ 85,533	$ 112,727	$ 94,573

Schedule - Valuation and Qual_2

Schedule - Valuation and Qualifying Accounts (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation allowances on deferred tax assets written off against the deferred tax assets	$ 7,588		$ 2,416
Accounts receivable allowances written off against related accounts receivables	$ 3,539	$ 6,659	3,008
Accounts receivable allowances were netted against deferred revenue			$ 5,291