Nuance Communications (NUAN) 10-K 19 Nov 20 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2020	Oct. 31, 2020	Mar. 31, 2020
Document Documentand Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-27038
Entity Registrant Name	NUANCE COMMUNICATIONS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3156479
Entity Address, Address Line One	1 Wayside Road
Entity Address, Postal Zip Code	01803
Entity Address, City or Town	Burlington,
Entity Address, State or Province	MA
City Area Code	781
Local Phone Number	565-5000
Title of 12(b) Security	Common stock, $0.001 par value
Trading Symbol	NUAN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Public Float			$ 3,900,000,000
Entity Common Stock, Shares Outstanding		282,953,777
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement to be delivered to stockholders in connection with the registrant’s 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10-K.
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0001002517
Current Fiscal Year End Date	--09-30
Entity Emerging Growth Company	false

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Hosting and professional services		$ 926,044	$ 913,643	$ 940,044
Product and licensing		296,127	338,693	375,230
Maintenance and support		256,728	268,935	252,326
Total revenues	[1]	1,478,899	1,521,271	1,567,600
Cost of revenues:
Hosting and professional services		518,145	551,419	608,286
Product and licensing		61,995	71,280	55,670
Maintenance and support		30,989	33,369	39,228
Amortization of intangible assets		27,810	27,416	40,218
Total cost of revenues		638,939	683,484	743,402
Gross profit		839,960	837,787	824,198
Operating expenses:
Research and development		226,234	192,633	207,189
Sales and marketing		273,324	274,031	286,550
General and administrative		156,353	172,638	213,809
Amortization of intangible assets		78,707	81,622	105,375
Intangible Assets Amortization Expense		50,897	54,206	65,157
Acquisition-related costs, net		2,884	7,965	12,010
Restructuring and other charges, net		17,680	29,147	52,846
Impairment of goodwill and other intangible assets		0	0	170,941
Total operating expenses		727,372	730,620	1,008,502
Income (loss) from operations		112,588	107,167	(184,304)
Other income (expense):
Interest income		4,527	13,705	9,327
Interest expense		(93,968)	(120,095)	(137,253)
Other expense, net		(13,117)	(870)	(1,767)
Income (loss) before income taxes		10,030	(93)	(313,997)
(Benefit) provision for income taxes		(18,752)	12,105	(77,160)
Net income (loss) from continuing operations		28,782	(12,198)	(236,837)
Net (loss) income from discontinued operations		(7,386)	226,008	76,909
Net income (loss)		$ 21,396	$ 213,810	$ (159,928)
Net income (loss) per common share - basic:
Continuing operations (per share)		$ 0.10	$ (0.04)	$ (0.81)
Discontinued operations (per share)		(0.02)	0.79	0.26
Total net income (loss) per basic common share (per share)		0.08	0.75	(0.55)
Continuing operations (per share)		0.10	(0.04)	(0.81)
Discontinued operations (per share)		(0.03)	0.79	0.26
Diluted (per share)		$ 0.07	$ 0.75	$ (0.55)
Weighted average common shares outstanding:
Basic (in shares)		282,644	286,347	291,318
Diluted (in shares)		291,994	286,347	291,318
[1]	Segment revenues differ from reported revenues due to certain revenue adjustments related to acquisitions that would otherwise have been recognized but for the purchase accounting treatment of the business combinations. These revenues are included to allow for more complete comparisons to the financial results of historical operations and in evaluating management performance.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Net income (loss)	$ 21,396	$ 213,810	$ (159,928)
Other comprehensive income (loss):
Foreign currency translation adjustment	2,167	(11,993)	(23,973)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	12,331	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0	5,605	0
Pension Adjustments	423	(3,768)	2,644
Unrealized (loss) gain on marketable securities	(66)	246	(192)
Total other comprehensive income (loss), net	14,855	(9,910)	(21,521)
Comprehensive income (loss)	$ 36,251	$ 203,900	$ (181,449)

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Current assets:
Cash and cash equivalents	$ 301,233	$ 560,961
Marketable securities	71,114	186,555
Accounts Receivable, after Allowance for Credit Loss, Current	200,576	240,673
Prepaid expenses and other current assets	163,062	175,166
Disposal Group, Including Discontinued Operation, Assets, Current	0	91,858
Total current assets	735,985	1,255,213
Marketable securities	0	17,287
Land, building and equipment, net	143,428	121,203
Goodwill	2,133,712	2,127,896
Intangible assets, net	213,484	291,371
Operating lease, Right-of-use Asset	110,276	0
Other Assets, Noncurrent	256,447	316,215
Total assets	3,593,332	5,365,793
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent	0	1,236,608
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	0	286,654
Current liabilities:
Current portion of long-term debt	432,209	1,142,870
Contingent and deferred acquisition payments	4,224	17,470
Accounts payable	75,122	90,826
Accrued expenses and other current liabilities	213,264	249,570
Deferred revenue	261,323	214,223
Disposal Group, Including Discontinued Operation, Liabilities, Current	0	130,117
Total current liabilities	986,142	1,845,076
Long-term portion of debt	1,104,464	793,536
Deferred Revenue, Noncurrent	104,309	133,783
Deferred Tax Liabilities, Other	70,116	54,216
Total liabilities	2,449,399	3,192,643
Stockholders' equity:
Common stock	287	290
Additional paid-in capital	1,550,568	2,597,889
Treasury stock, at cost	(16,788)	(16,788)
Accumulated other comprehensive loss	(117,918)	(132,773)
Accumulated deficit	(272,216)	(293,612)
Total Nuance Communications, Inc. stockholders' equity	1,143,933	2,155,006
Noncontrolling interests	0	18,144
Total liabilities and stockholders’ equity	3,593,332	5,365,793
Operating Lease, Liability, Noncurrent	107,621	0
Other Liabilities, Noncurrent	76,747	79,378
Members' Equity	$ (1,143,933)	$ (2,173,150)

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Accounts receivable, allowances for doubtful accounts	$ 11,115	$ 9,797
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	560,000,000	560,000,000
Common stock, shares issued	286,703,000	289,680,000
Common stock, shares outstanding	282,952,000	285,929,000
Treasury stock, shares	3,751,000	3,751,000

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Noncontrolling Interest [Member]	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle	$ (882)	$ 0	$ 0	$ 0	$ 0	$ 0	$ (882)
Beginning balance (in shares) at Sep. 30, 2017		293,938			(3,751)
Beginning balance at Sep. 30, 2017	1,931,382	$ 294	2,629,245	$ 0	$ (16,788)	(101,342)	(580,027)
Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock plans (in shares)		10,568		0
Issuance of common stock under employee stock plans	18,384	$ 10	18,374		0	0	0
Cancellation of restricted stock, and repurchase of common stock at cost for employee tax withholding (in shares)		(3,304)
Cancellation of restricted stock, and repurchase of common stock at cost for employee tax withholding	(52,336)	$ (3)	(52,333)	$ 0	0	0	0
Stock-based compensation	$ 138,487	$ 0	138,487	0	0	0	0
Repurchase of common stock (in shares)	(9,700)	(9,698)
Repurchase of common stock	$ (136,090)	$ (10)	(136,080)	0	0	0	0
Net income (loss)	(159,928)	0	0	0	0	0	(159,928)
Other comprehensive income (loss)	(21,521)	$ 0	0	0	$ 0	(21,521)	0
Ending balance (in shares) at Sep. 30, 2018		291,504			(3,751)
Ending balance at Sep. 30, 2018	1,717,496	$ 291	2,597,693	0	$ (16,788)	(122,863)	(740,837)
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle	233,415	$ 0	0	0	0	0	233,415
Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock plans (in shares)		8,981
Issuance of common stock under employee stock plans	16,597	$ 9	16,588	0	0	0	0
Cancellation of restricted stock, and repurchase of common stock at cost for employee tax withholding (in shares)		(2,645)
Cancellation of restricted stock, and repurchase of common stock at cost for employee tax withholding	(42,554)	$ (2)	(42,552)	0	0	0	0
Stock-based compensation	$ 161,371	$ 0	161,371	0	0	0	0
Repurchase of common stock (in shares)	(8,200)	(8,160)
Repurchase of common stock	$ (126,938)	$ (8)	(126,930)	0	0	0	0
Noncontrolling Interest, Increase from Sale of Parent Equity Interest	9,863		(8,281)	18,144
Net income (loss)	213,810	0	0	0	0	0
Other comprehensive income (loss)	(9,910)	$ 0	0	0	$ 0	(9,910)	0
Ending balance (in shares) at Sep. 30, 2019		289,680			(3,751)
Ending balance at Sep. 30, 2019	2,155,006	$ 290	2,597,889	18,144	$ (16,788)	(132,773)	(293,612)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	2,173,150
Stockholders' Equity Note, Spinoff Transaction	(928,380)	$ 0	(922,567)	(18,144)	0	12,331	0
Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock plans (in shares)		9,387
Issuance of common stock under employee stock plans	14,840	$ 9	14,831	0	0	0	0
Cancellation of restricted stock, and repurchase of common stock at cost for employee tax withholding (in shares)		(2,907)
Cancellation of restricted stock, and repurchase of common stock at cost for employee tax withholding	56,460	$ (3)	(56,457)	0	0	0	0
Stock-based compensation	$ 132,201	$ 0	132,201	0	0	0	0
Repurchase of common stock (in shares)	(9,500)	(9,457)
Repurchase of common stock	$ 169,217	$ (9)	(169,208)	0	0	0	0
Stock Issued During Period, Shares, Conversion of Convertible Securities		0
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments	46,121	$ 0	(46,121)	0	0	0	0
Net income (loss)	21,396	0	0	0	0	0	21,396
Other comprehensive income (loss)	14,855	$ 0	0	0	$ 0	2,524	0
Ending balance (in shares) at Sep. 30, 2020		286,703			(3,751)
Ending balance at Sep. 30, 2020	1,143,933	$ 287	$ 1,550,568	$ 0	$ (16,788)	$ (117,918)	$ (272,216)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,143,933

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income (loss)	$ 21,396	$ 213,810	$ (159,928)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	28,782	(12,198)	(236,837)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Amortization of intangible assets	78,707	81,622	105,375
Depreciation	37,772	47,417	51,426
Stock-based compensation	133,294	119,255	127,043
Non-cash interest expense	49,440	49,488	49,091
Deferred tax (benefit) provision	(39,937)	(12,437)	(88,407)
Loss on extinguishment of debt	18,656	910	(348)
Impairment of goodwill and other intangible assets	0	0	170,941
Other Asset Impairment Charges	0	0	10,550
Other	2,736	4,462	2,230
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	42,075	3,366	6,168
Prepaid expenses and other assets	(7,259)	(21,063)	(8,009)
Accounts payable	(8,173)	12,122	(7,909)
Accrued expenses and other liabilities	(84,076)	27,415	12,166
Deferred revenue	15,854	4,227	47,499
Net cash provided by operating activities	254,564	401,357	444,426
Net Cash Provided by (Used in) Continuing Operations	267,871	304,586	240,979
Cash Provided by (Used in) Operating Activities, Discontinued Operations	(13,307)	96,771	203,447
Cash flows from investing activities:
Capital expenditures	(61,297)	(44,185)	(48,845)
Proceeds from Divestiture of Businesses	150	407,043	0
Payments for business and technology acquisitions, net of cash acquired	(1,000)	(20,873)	(110,170)
Payments for (Proceeds from) Other Investing Activities	1,147	0	0
Purchases of marketable securities and other investments	(180,005)	(349,125)	(201,995)
Proceeds from sales and maturities of marketable securities and other investments	313,734	303,171	323,695
Net cash used in investing activities	72,729	296,031	(37,315)
Cash flows from financing activities:
Payments of long-term debt	(513,642)	(300,000)	(481,172)
Proceeds from Equity Method Investment, Distribution, Return of Capital	139,090	0	0
Payments for repurchase of common stock	(169,217)	(126,938)	(136,090)
Payment for Contingent Consideration Liability, Financing Activities	0	0	(24,842)
Payments on other long-term liabilities	(3,222)	(2,131)	(1,232)
Proceeds from issuance of common stock from employee stock plans	14,840	16,597	18,384
Proceeds from Lines of Credit	230,000	0	0
Proceeds from (Repayments of) Lines of Credit	(230,000)	0	0
Cash used to net share settle employee equity awards	(54,056)	(49,428)	(55,396)
Proceeds from Divestiture of Interest in Subsidiaries and Affiliates	0	9,863	0
Net cash provided by financing activities	(586,207)	(452,037)	(680,348)
Effects of exchange rate changes on cash and cash equivalents	(814)	(353)	(3,099)
Net increase (decrease) in cash and cash equivalents	(259,728)	244,998	(276,336)
Cash and cash equivalents at beginning of year	560,961	315,963	592,299
Cash and cash equivalents at end of year	$ 301,233	$ 560,961	$ 315,963

Organization and Presentation

Organization and Presentation	12 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Presentation	Organization and Presentation Nuance Communications, Inc. ("We", "Nuance", or the "Company") is a pioneer and leader in conversational and cognitive AI innovations that bring intelligence to everyday work and life. Our solutions and technologies can understand, analyze and respond to human language to increase productivity and amplify human intelligence. Our solutions are used by businesses in the healthcare, financial services, telecommunications and travel industries, among others. We have three reportable segments as of September 30, 2020 : Healthcare, Enterprise, and Other. See Note 23 for a description of each of these segments. As more fully described in Note 10 , during the fourth quarter of fiscal year 2020, our common stock price exceeded the conversion threshold price, which equals 130% of the conversion price specified in the debenture for at least 20 trading days during the 30 consecutive trading days ending September 30, 2020. As a result, our 1.25% 2025 Debentures and 1.5% 2035 Debentures are convertible any time between October 1, 2020 and December 31, 2020 at the option of the holders. Additionally, with the current increase in our market price, we expect the 1.0% 2035 Debenture will also become convertible as of December 31, 2020. Accordingly, the principal amounts of convertible debentures total $1,167 million likely will be convertible from December 31, 2020 through March 31, 2021 and other future periods should the stock price continue to exceed the conversion price for at least 20 trading days during the 30 consecutive trading days ending each quarter. Should any holders elect to convert, the principal amount of the convertible debentures would be payable in cash and any amount payable in excess of the principal amount, based upon the conversion ratio specified in the indenture, would be paid in cash or shares of our common stock at our election. Our convertible debentures are actively traded in the open market and consistently at a trading price in excess of their conversion values. Therefore, we believe that it is uneconomic, and thus unlikely for the holders to early exercise their conversion rights with Nuance. In the event that the holders presented an amount for settlement that exceeded our then available sources of liquidity, we may possibly need to obtain additional financing, which we believe would be available to us based upon our assessment of the prevailing market and business conditions and our experience of successful capital raising activities.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2 . Summary of Significant Accounting Policies Use of Estimates The consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles ("GAAP"), which requires management to make estimates and assumptions. These estimates, judgments and assumptions can affect the reported amounts in the financial statements and the footnotes thereto. Actual results could differ materially from these estimates. On an ongoing basis, we evaluate our estimates, assumptions and judgments. Significant estimates inherent to the preparation of financial statements include: revenue recognition; the allowances for doubtful accounts and sales returns; contract assets; internally developed software; goodwill and intangible assets; business combinations, including contingent consideration; and income taxes, including valuation allowance and uncertain tax positions. We base our estimates on historical experience, market participant fair value considerations, projected future cash flows, and various other factors that are believed to be reasonable under the circumstances. Actual amounts could differ significantly from these estimates. Basis of Consolidation The consolidated financial statements include the accounts Nuance and our subsidiaries. Intercompany transactions and balances have been eliminated. Revenue Recognition under ASC 605 for fiscal year 2018 We derive revenue from the following sources: (1) software license agreements, including royalty and other usage-based arrangements, (2) professional services, (3) hosting services and (4) post-contract customer support ("PCS"). Our hosting services are generally provided through on-demand, usage-based or per transaction fee arrangements. Generally, we recognize revenue when (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred, (iii) the fee is fixed or determinable and (iv) collectibility is probable. The sale and/or license of software solutions and technology is deemed to have occurred when a customer either has taken possession of or has access to take immediate possession of the software or technology. Revenue from royalties on sales of our software products by original equipment manufacturers (“OEMs”), where no services are included, is recognized in the quarter earned so long as we have been notified by the OEM that such royalties are due, and provided that all other revenue recognition criteria are met. Software arrangements generally include PCS, which includes telephone support and the right to receive unspecified upgrades/enhancements on a when-and-if-available basis, typically for one to five years. Revenue from PCS is generally recognized ratably on a straight-line basis over the term that the maintenance service is provided. When PCS renews automatically, we provide a reserve based on historical experience for contracts expected to be canceled for non-payment. All known and estimated cancellations are recorded as a reduction to revenue and accounts receivable. When we provide professional services considered essential to the functionality of the software, we recognize revenue from the professional services as well as any related software licenses on a percentage-of-completion basis whereby the arrangement consideration is recognized as the services are performed, as measured by an observable input. In these circumstances, we separate license revenue from professional service revenue for income statement presentation by allocating Vendor-Specific Objective Evidence ("VSOE") of fair value of the professional services as professional services and hosting revenue and the residual portion as product and licensing revenue . We generally determine the percentage-of-completion by comparing the labor hours incurred to-date to the estimated total labor hours required to complete the project. Adjustments to estimates to complete are made in the periods in which facts resulting in a change become known. When the estimate indicates that a loss will be incurred, such loss is recorded in the period identified. In a hosting arrangement, we recognize the up-front setup fees ratably over the longer of the contract lives or the expected lives of the customer relationships. The usage-based or individual transaction fees are due and payable as each individual transaction is processed through the hosting service and is recognized as revenue in the period the services are provided. The on-demand service fees are recognized ratably over our estimate of the useful life of the devices on which the hosting service is provided. We enter into multiple-element arrangements that may include a combination of our various software related and non-software related products and services offerings, for example, software licenses, PCS, professional services, and hosting services. In such arrangements, we allocate total arrangement consideration to software or software-related elements and any non-software element separately based on the selling price hierarchy group following our policies. Where possible, we determine the selling price for each deliverable using VSOE of selling price, if it exists, or Third-Party Evidence (“TPE”) of selling price. Typically, we are unable to determine TPE of selling price. Therefore, when neither VSOE nor TPE of selling price exist for a deliverable, we use our Estimate of Selling Price (“ESP”) for the purposes of allocating the arrangement consideration. We determine ESP for a product or service by considering multiple factors including, but not limited to, major project groupings, market conditions, competitive landscape, price list and discounting practices. We have established VSOE of fair value for the majority of our PCS, professional services, and training. Revenue allocated to each element is then recognized when the basic revenue recognition criteria are met for each element. See Note 3 for revenue recognition under ASC 606 for fiscal years 2020 and 2019. Business Combinations We determine and allocate the purchase price of an acquired company to the tangible and intangible assets acquired and liabilities assumed as of the date of acquisition. Results of operations and cash flows of acquired companies are included in our operating results from the date of acquisition. The purchase price allocation process requires us to use significant estimates and assumptions, which include: • estimated fair values of intangible assets; • estimated fair values of legal performance commitments to customers, assumed from the acquiree under existing contractual obligations (classified as deferred revenue); • estimated fair values of stock awards assumed from the acquiree that are included in the purchase price; • estimated fair value of required payments under contingent consideration provisions; • estimated income tax assets and liabilities assumed from the acquiree; and • estimated fair value of pre-acquisition contingencies assumed from the acquiree. The fair value of any contingent consideration is established at the acquisition date and included in the total purchase price. The contingent consideration is then adjusted to fair value, with any measurement-period adjustment recorded against goodwill. Adjustments identified subsequent to the measurement period are recorded within Acquisition-related costs, net. While we use our best estimates and assumptions as part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the business combination date, our estimates and assumptions are inherently uncertain and subject to refinement. As a result, during the measurement period, which is generally one year from the acquisition date, any adjustment to the assets acquired and liabilities assumed is recorded against goodwill in the period in which the amount is determined. Any adjustment identified subsequent to the measurement period is included in operating results in the period in which the amount is determined. Goodwill Goodwill represents the excess of the purchase price in a business combination over the fair value of net tangible and intangible assets acquired. Goodwill and intangible assets with indefinite lives are not amortized, but rather the carrying amounts of these assets are assessed for impairment at least annually or whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Goodwill is tested for impairment annually on July 1, the first day of the fourth quarter of the fiscal year. Goodwill impairment, if any, is determined by comparing the reporting unit's fair value to its carrying value. An impairment loss is recognized in an amount equal to the excess of the reporting unit's carrying value over its fair value, up to the amount of goodwill allocated to the reporting unit. There was no goodwill impairment for fiscal year 2020. See Note 6 for the impairment charges recorded in fiscal year 2018. For the purpose of testing goodwill for impairment, all goodwill acquired in a business combination is assigned to one or more reporting units. A reporting unit represents an operating segment or a component within an operating segment for which discrete financial information is available and is regularly reviewed by segment management for performance assessment and resource allocation. Components of similar economic characteristics are aggregated into one reporting unit for the purpose of goodwill impairment assessment. Reporting units are identified annually and re-assessed periodically for recent acquisitions or any changes in segment reporting structure. Corporate assets and liabilities are allocated to each reporting unit based on the reporting unit’ revenue, total operating expenses or operating income as a percentage of the consolidated amounts. Corporate debt and other financial liabilities that are not directly attributable to the reporting unit's operations and would not be transferred to hypothetical purchasers of the reporting units are excluded from a reporting unit's carrying amount. The fair value of a reporting unit is generally determined using a combination of the income approach and the market approach, where the income approach is weighted 50% and the market approach 50%. For the income approach, fair value is determined based on the present value of estimated future after-tax cash flows, discounted at an appropriate risk-adjusted rate. We use our internal forecasts to estimate future after-tax cash flows and estimate the long-term growth rates based on our most recent views of the long-term outlook for each reporting unit. Actual results may differ from those assumed in our forecasts. We derive our discount rates using a capital asset pricing model and analyzing published rates for industries relevant to our reporting units to estimate the weighted average cost of capital. We adjust the discount rates for the risks and uncertainty inherent in the respective businesses and in our internally developed forecasts. For the market approach, we use a valuation technique in which values are derived based on valuation multiples of comparable publicly traded companies. We assess each valuation methodology based upon the relevance and availability of the data at the time we perform the valuation and weight the methodologies appropriately. Long-Lived Assets with Definite Lives Our long-lived assets consist principally of technology, customer relationships, internally developed software, land, and building and equipment. Customer relationships are amortized over their estimated economic lives based on the pattern of economic benefits expected to be generated from the use of the asset. Other definite-lived assets are amortized over their estimated economic lives using the straight-line method. The remaining useful lives of long-lived assets are re-assessed periodically for any events and circumstances that may change the future cash flows expected to be generated from the long-lived asset or asset group. Internally developed software consists of capitalized costs incurred during the application development stage, which include costs related design of the software configuration and interfaces, coding, installation and testing. Costs incurred during the preliminary project stage and post-implementation stage are expensed as incurred. Internally developed software is amortized over the estimated useful life, commencing on the date when the asset is ready for its intended use. Land, building and equipment are stated at cost and depreciated over their estimated useful lives. Leasehold improvements are depreciated over the shorter of the related lease term or the estimated useful life. Depreciation is computed using the straight-line method. Repair and maintenance costs are expensed as incurred. The cost and related accumulated depreciation of sold or retired assets are removed from the accounts and any gain or loss is included in the results of operations for the period. Long-lived assets with definite lives are tested for impairment whenever events or changes in circumstances indicate the carrying value of a specific asset or asset group may not be recoverable. We assess the recoverability of long-lived assets with definite lives at the asset group level. Asset groups are determined based upon the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. When the asset group is also a reporting unit, goodwill assigned to the reporting unit is also included in the carrying amount of the asset group. For the purpose of the recoverability test, we compare the total undiscounted future cash flows from the use and disposition of the assets with its net carrying amount. When the carrying value of the asset group exceeds the undiscounted future cash flows, the asset group is deemed to be impaired. The amount of the impairment loss represents the excess of the asset or asset group’s carrying value over its estimated fair value, which is generally determined based upon the present value of estimated future pre-tax cash flows that a market participant would expect from use and disposition of the long-lived asset or asset group. There was no intangible asset impairment for fiscal year 2020. See Note 6 for the impairment charges recorded in fiscal year 2018. Cash and Cash Equivalents Cash and cash equivalents consist of cash on hand, including money market funds and time deposits with original maturities of 90 days or less. Marketable Securities Marketable securities consist of time deposits and high-quality corporate debt instruments with stated maturities of more than 90 days. Investments are classified as available-for-sale and are recorded on the balance sheet at fair value with unrealized gains or losses reported as a separate component of accumulated other comprehensive loss, net of tax. Accounts Receivable Allowances Allowances for Doubtful Accounts. We record allowances for doubtful accounts for the estimated probable losses on uncollectible accounts receivable. The allowance is based upon the credit worthiness of our customers, our historical experience, the age of the receivable and current market and economic conditions. Receivables are written off against these allowances in the period they are determined to be uncollectible. Allowances for Sales Returns. We reduce transaction price for estimated returns and other allowances that represent variable considerations based on historical experience and other relevant factors. The returns allowance is recorded as a reduction to revenue and accounts receivable at the time the related revenue is recorded. Receivables are written off against the allowance in the period the return is received. For the years ended September 30, 2020 , 2019 and 2018 , the activity related to accounts receivable allowances was as follows (dollars in thousands): Allowance for Doubtful Accounts Allowance for Sales Returns Balance at September 30, 2017 $ 11,106 $ 29,541 Bad debt provision 2,011 — Write-offs, net of recoveries (4,248 ) — Revenue adjustments, net (a) — (23,396 ) Balance at September 30, 2018 8,869 6,145 Bad debt provisions 2,375 — Write-offs, net of recoveries (1,447 ) — Revenue adjustments, net — (1,554 ) Balance at September 30, 2019 9,797 4,591 Bad debt provisions 2,117 — Write-offs, net of recoveries (799 ) — Revenue adjustments, net — (935 ) Balance at September 30, 2020 $ 11,115 $ 3,656 (a) The decrease in provisions was primarily due to the resolution of the reserves related to the 2017 Malware Incident. Software Development Costs We expense software development costs, including costs to develop software products or the software component of products to be sold, leased, or marketed to external users, before technological feasibility is reached. Technological feasibility is typically reached shortly before the release of such products and as a result, development costs that meet the criteria for capitalization were not material for the periods presented. Software development costs also include costs to develop software to be used solely to meet internal needs and cloud-based applications used to deliver our services. We capitalize development costs related to these software applications once the preliminary project stage is complete and it is probable that the project will be completed, and the software will be used to perform the function intended. As of September 30, 2020 and 2019 , the net book value of capitalized internal-use software costs was $55.6 million and $26.3 million , respectively, which are included within Land, buildings and equipment, net. Acquisition-Related Costs, Net Acquisition-related costs, net include costs related to business and other acquisitions, including potential acquisitions. These costs consist of (i) transition and integration costs, including retention payments, transitional employee costs and earn-out payments, and other costs related to integration activities; (ii) professional service fees, including financial advisory, legal, accounting, and other outside services incurred in connection with acquisition activities, and disputes and regulatory matters related to acquired entities; and (iii) fair value adjustments to acquisition-related contingencies. The components of acquisition-related costs, net were as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Transition and integration costs $ 3,778 $ 7,568 $ 14,443 Professional service fees (23 ) 1,940 983 Acquisition-related adjustments (871 ) (1,543 ) (3,416 ) Total $ 2,884 $ 7,965 $ 12,010 Advertising Costs Advertising costs are expensed as incurred and recorded within sales and marketing expenses. The advertising costs capitalized as of September 30, 2020 and 2019 are de minimis. We incurred advertising costs of $16.1 million , $16.9 million and $16.5 million for fiscal years 2020 , 2019 and 2018 , respectively. Convertible Debt We bifurcate the debt and equity (the contingently convertible feature) components of our convertible debt instruments in a manner that reflects our nonconvertible debt borrowing rate at the time of issuance. The equity components of our convertible debt instruments are recorded within stockholders’ equity with an allocated issuance premium or discount. The debt issuance premium or discount is amortized to interest expense in our consolidated statement of operations using the effective interest method over the expected term of the convertible debt. We assess the short-term and long-term classification of our convertible debt on each balance sheet date. The carrying amount of the convertible debt is reclassified to current liabilities if a contingent event has occurred that makes the debt obligation puttable. The corresponding equity component classified from additional paid-in capital to mezzanine equity when the holders have the contractual rights to redeem or convert. Income Taxes We account for income taxes using the asset and liability method, under which we recognize the amount of taxes payable or refundable for the current year and deferred tax assets and liabilities for the future tax consequences of events that have been recognized in our financial statements or tax returns. We measure current and deferred tax assets and liabilities based on provisions of enacted tax law. We evaluate the realization of our deferred tax assets based on all available evidence and establish a valuation allowance to reduce deferred tax assets when it is more likely than not that they will not be realized. We recognize the financial statement effects of a tax position when it is more likely than not that, based on technical merits, the position will be sustained upon examination. The tax benefits of the position recognized in the financial statements are then measured based on the largest amount of benefit that is greater than 50% likely to be realized upon settlement with a taxing authority. In addition, we recognize interest and penalties related to unrecognized tax benefits as a component of the income tax provision. Accumulated Other Comprehensive Loss The components of accumulated other comprehensive loss, reflected in the consolidated statements of stockholders’ equity, consisted of the following (dollars in thousands): September 30, 2020 September 30, 2019 Foreign currency translation adjustment $ (110,110 ) $ (124,608 ) Net unrealized losses on post-retirement benefits (7,873 ) (8,296 ) Unrealized gain (loss) on marketable securities 65 131 Accumulated other comprehensive loss $ (117,918 ) $ (132,773 ) No income tax provisions or benefits are recorded for foreign currency translation adjustment as the undistributed earnings in our foreign subsidiaries are expected to be indefinitely reinvested. Concentration of Risk Financial instruments that are potentially subject to significant concentrations of credit risk principally consist of cash, cash equivalents, marketable securities and trade accounts receivable. We place our cash and cash equivalents and marketable securities with financial institutions with high credit ratings. As part of our cash and investment management processes, we perform periodic evaluations of the credit standing of the financial institutions with whom we maintain deposits, and have not recorded any credit losses to-date. For trade accounts receivable, we perform ongoing credit evaluations of our customers’ financial condition and limit the amount of credit extended when deemed appropriate. No customer accounted for more than 10% of our net accounts receivable balance at September 30, 2020 and 2019 or 10% of our revenue for fiscal years 2020 , 2019 or 2018 . Foreign Currency Translation The functional currency of a foreign subsidiary is generally the local currency. We translate the financial statements of foreign subsidiaries to U.S. dollars using month-end exchange rates for assets and liabilities, and average rates for the reporting period for revenues, costs, and expenses. We record translation gains and losses in accumulated other comprehensive loss as a component of stockholders’ equity. We record net foreign exchange transaction gains and losses resulting from the conversion of the transaction currency to the functional currency within in other expense, net . Foreign currency transaction gains (losses)for fiscal years 2020 , 2019 and 2018 were $1.3 million , $1.1 million and $(1.2) million , respectively. Financial Instruments and Hedging Activities We use forward currency exchange contracts to manage our exposure to fluctuations in foreign currency for certain transactions. In order for instruments to be designated as hedges, specific criteria must be met, including (i) formal documentation must exist for both the hedging relationship and our risk management objectives and strategies for undertaking the hedging activities, (ii) at the inception and on an ongoing basis, the hedging relationship is expected to be highly effective in offsetting changes in fair value attributed to the hedged risk during the period that the hedge is designated, and (iii) an assessment of effectiveness is required whenever financial statements or earnings are reported. The effective portion of changes in the fair values of contracts designated as cash flow hedges is recorded in equity as a component of accumulated other comprehensive loss until the hedged item effects earnings. Once the underlying forecasted transaction is realized, the changes of fair vales of instruments designated as hedges reclassified from accumulated other comprehensive loss to the statement of operations, in the appropriate income statement line items. Any ineffective portion of the instruments designated as cash flow hedges is recognized in current earnings. We report cash flows arising from derivative financial instruments designated as fair value or cash flow hedges consistent with the classification of the cash flows from the underlying hedged items that these derivatives are hedging. No forward exchange contracts are designated as hedges for fiscal years 2020 , 2019 , or 2018 . Changes in the fair values of the forward currency exchange contracts are recorded within other expense, net . Cash flows related to investments and settlements of forward currency exchange contracts are included within cash flows from investing activities. Stock-Based Compensation Stock-based compensation primarily consists of restricted stock units with service, and market or performance conditions. Equity awards are measured at the fair market value of the underlying stock at the grant date. We recognize stock compensation expense ratably over the requisite service period and account for forfeitures based on our estimates. Shares are issued on the vesting dates net of the applicable statutory tax withholding to be paid by us on behalf of our employees. As a result, fewer shares are issued than the number of awards outstanding. We record a liability for the tax withholding to be paid by us as a reduction to additional paid-in capital. We record any income tax effect related to stock-based awards through the consolidated statements of operations. Excess tax benefits are recognized as deferred tax assets upon settlement and are subject to regular review for valuation allowance. Net Income (Loss) Per Share Basic net income or loss per share is computed using the weighted-average number of common shares outstanding during the period. Diluted net income or loss per share is computed using the weighted-average number of common shares, giving effect to potentially dilutive securities outstanding during the period. Potentially dilutive securities consist of stock options, restricted stock units, contingently issuable shares under earn-out agreements, and potential issuance of stock upon conversion of our convertible debentures, as more fully described in Note 10 . In the event of conversion, we are required to settle the principal amount of the convertible debentures, with any accrued and unpaid interest in cash, and may settle the conversion spread in either cash or common stock at our election. Therefore, only the shares of common stock potentially issuable upon conversion are included within the diluted common shares for the reporting period, during which our average stock price exceeds the conversion price. Recently Adopted Accounting Standards Leases In February 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-02, "Leases" ("ASC 842"), which became effective for fiscal years beginning after December 15, 2018 and interim periods therein, with early adoption permitted. ASC 842 requires lessees to recognize on the balance sheet a right-of-use asset, representing its right to use the underlying asset for the lease term, and a lease liability for all leases with terms greater than 12 months. The guidance also requires qualitative and quantitative disclosures designed to assess the amount, timing, and uncertainty of cash flows arising from leases. The standard initially required the use of a modified retrospective transition approach, which includes a number of optional practical expedients that entities may elect to apply. We adopted ASC 842 in the first quarter of fiscal year 2020. In July 2018, the FASB issued ASU 2018-10, "Codification Improvements to Topic 842, Leases" and ASU 2018-11, "Leases Topic 842 Targeted Improvements", which provide an additional (and optional) transition method whereby the new lease standard is applied at the adoption date and recognized as an adjustment to retained earnings. Additionally, in March 2019, the FASB issued ASU 2019-01, "Codification Improvements to Topic 842", which provides guidance in the following areas: (1) determining the fair value of the underlying asset by lessors that are not manufacturers or dealers and (2) clarification of interim disclosure requirements during transition. We adopted ASC 842, as amended, as of October 1, 2019 under the optional transition method and elected the package of practical expedients under the transition guidance. As a result of the adoption on October 1, 2019, we recognized $120 million of operating lease right-of-use assets, and approximately $140 million of operating lease obligations. Approximately $20 million of deferred rent balances were reclassified against the costs of the right-of-use assets. The cumulative-effect adjustment to retained earnings as of October 1, 2019 was immaterial. The adoption of the guidance did not have a material impact on our consolidated statement of operations or consolidated statement of cash flows. Income Taxes In January 2018, the FASB issued ASU 2018-02, "Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income ("AOCI"), which became effective for fiscal years beginning after December 15, 2018 and interim periods therein. The guidance gives entities the option to reclassify to retained earnings the tax effects resulting from the TCJA related to items in AOCI. The guidance may be applied retrospectively to each period in which the effect of the TCJA is recognized in the period of adoption. The adoption of the guidance did not have a material impact on our condensed consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, "Income Taxes (Topic 840): Simplifying the Accounting for Income Taxes", which will become effective for fiscal years beginning after 15 December 2020 and interim periods therein. Early adoption is permitted for entities that have not yet issued their financial statements. The guidance simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in ASC 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. We adopted the guidance prospectively for fiscal year 2020. The adoption has no impact on our consolidated financial statements for fiscal years 2020, 2019 and 2018. Issued Accounting Standards Not Yet Adopted From time to time, new accounting pronouncements are issued by the FASB and are adopted by us as of the specified effective dates. Unless otherwise discussed, such pronouncements did not have or will not have a significant impact on our consolidated financial position, results of operations or cash flows, or do not apply to our operations. Internal-Use Software In August 2018, the FASB issued ASU 2018-15, "Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract", which is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, with early adoption permitted. The guidance requires that implementation costs related to a hosting arrangement that is a service contract be capitalized and amortized over the term of the hosting arrangement, starting when the module or component of the hosting arrangement is ready for its intended use. The guidance will be applied retrospectively to each period presented. We do not expect the implementation to have a material impact on our condensed consolidated financial statements. Convertible Notes In August 2020, the FASB issued ASU 2020-06, "Debt - Debt with Conversi

Revenue Recognition (Notes)

Revenue Recognition (Notes)	12 Months Ended
	Sep. 30, 2020
Revenue Recognition [Abstract]
Revenue from Contract with Customer [Text Block]	3 . Revenue Recognition We derive revenue from the following sources: (1) hosting services, (2) software licenses, including royalties, (3) M&S, (4) professional services, and (5) sale of hardware. Revenue is reported net of applicable sales and use tax, value-added tax and other transaction taxes imposed on the related transaction including mandatory government charges that are passed through to our customers. We account for a contract when both parties have approved and committed to the contract, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and the collectability of the consideration is probable. The majority of our arrangements with customers typically contain multiple products and services. We account for individual products and services separately if they are distinct--that is, if a product or service is separately identifiable from other items in the contract and if a customer can benefit from it on its own or with other resources that are readily available to the customer. We recognize revenue after applying the following five steps: • identification of the contract, or contracts, with a customer; • identification of the performance obligations in the contract, including whether they are distinct within the context of the contract; • determination of the transaction price, including the constraint on variable consideration; • allocation of the transaction price to the performance obligations in the contract; and • recognition of revenue when, or as, performance obligations are satisfied. We allocate the transaction price of the arrangement based on the relative estimated SSP of each distinct performance obligation. In determining SSP, we maximize observable inputs and consider a number of data points, including: • the pricing of standalone sales (in the instances where available); • the pricing established by management when setting prices for deliverables that are intended to be sold on a standalone basis; • contractually stated prices for deliverables that are intended to be sold on a standalone basis; and • other pricing factors, such as the geographical region in which the products are sold, and expected discounts based on the customer size and type. We only include estimated amounts of variable consideration in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. We reduce transaction prices for estimated returns and other allowances that represent variable consideration under ASU No. 2014-09, "Revenue from Contracts with Customers: Topic 606" ("ASC 606"), which we estimate based on historical return experience and other relevant factors and record a reduction to revenue and accounts receivable. Other forms of contingent revenue or variable consideration are infrequent. Revenue is recognized when control of these products and services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those services. We assess the timing of the transfer of products or services to the customer as compared to the timing of payments to determine whether a significant financing component exists. In accordance with the practical expedient in ASC 606-10-32-18, we do not assess the existence of a significant financing component when the difference between payment and transfer of deliverables is a year or less. If the difference in timing arises for reasons other than the provision of financing to either the customer or us, no financing component is deemed to exist. The primary purpose of our invoicing terms is to provide customers with simplified and predictable ways of purchasing our services, not to receive or provide financing from or to customers. We do not consider set-up fees nor other upfront fees paid by our customers to represent a financing component. Certain products are sold through distributors or resellers. Certain distributors and resellers have been granted right of return and selling incentives which are accounted for as variable consideration when estimating the amount of revenue to be recognized. Returns and credits are estimated at the contract inception and updated at the end of each reporting period as additional information becomes available. In accordance with the practical expedient in ASC 606-10-10-4, we apply a portfolio approach to estimate the variable consideration associated with this group of customers. Reimbursements for out-of-pocket costs generally include, but are not limited to, costs related to transportation, lodging and meals. Revenue from reimbursed out-of-pocket costs is accounted for as variable consideration. Shipping and handling activities are not considered a contract performance obligation. We record shipping and handling costs billed to customers as revenue with offsetting costs recorded as cost of revenue. Performance Obligations Hosting Hosting services, which allow our customers to use the hosted software over the contract period without taking possession of the software, are provided on a usage basis as consumed or on a fixed fee subscription basis. Our hosting contract terms generally range from one to five years. As each day of providing services is substantially the same and the customer simultaneously receives and consumes the benefits as access is provided, we have determined that our hosting services arrangements are a single performance obligation comprised of a series of distinct services. These services include variable consideration, which is typically a function of usage. We recognize revenue as each distinct service period is performed (i.e., recognized as incurred). Subscription-based revenue represents a single promise to stand-ready to provide access to our hosting services. Revenue is recognized over time on a ratable basis over the hosting contract term, which generally ranges from one to five years. Software Licenses On-premise software licenses sold with non-distinct professional services to customize and/or integrate the underlying software are accounted for as a combined performance obligation. Revenue from the combined performance obligation is recognized over time based upon the progress towards completion of the project, which is measured based on the labor hours already incurred to date as compared to the total estimated labor hours. Revenue from distinct on-premise software licenses, which do not require professional services to customize and/or integrate the software license, is recognized at the point in time when the software is made available to the customer and control is transferred. Revenue from software licenses sold on a royalty basis, where the license of intellectual property is the predominant item to which the royalty relates, is recognized in the period the usage occurs in accordance with the practical expedient in ASC 606-10-55-65(A). Maintenance and Support Our M&S contracts generally include telephone support and the right to receive unspecified upgrades and updates on a when-and-if available basis. M&S revenue is recognized over time on a ratable basis over the contract period because we transfer control evenly by providing a stand-ready service. Professional Services Revenue from distinct professional services, including training, is recognized over time based upon the progress towards completion of the project, which is measured based on the labor hours already incurred to date as compared to the total estimated labor hours. Hardware Hardware revenue is recognized at the point in time when control is transferred to the customer, which is typically upon delivery. Significant Judgments Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Our license contracts often include professional services to customize and/or integrate the licenses into the customer’s environment. Judgment is required to determine whether the license is considered distinct and accounted for separately, or not distinct and accounted for together with professional services. Judgments are required to determine the SSP for each distinct performance obligation. When SSP is directly observable, we estimate SSP based upon the historical transaction prices, adjusted for geographic considerations, customer classes, and customer relationship profiles. In instances where SSP is not directly observable, we determine SSP using information that may include market conditions and other observable inputs. We may have more than one SSP for individual products and services due to the stratification of those products and services by customers and circumstances. In these instances, we may use information such as the size of the customer and geographic region in determining SSP. Determining SSP for performance obligations which we never sell separately also requires significant judgment. In estimating the SSP for such performance obligations, we consider the likely price that would have resulted from established pricing practices had the deliverable been offered separately and the prices a customer would likely be willing to pay. From time to time, we may enter into arrangements with third party suppliers to resell products or services. In such cases, we evaluate whether we are the principal (i.e. report revenues on a gross basis) or agent (i.e. report revenues on a net basis). In doing so, we first evaluate whether we control the good or service before it is transferred to the customer. If we control the good or service before it is transferred to the customer, we are the principal; if not, we are the agent. Generally, we control a promised good or service before transferring that good or service to the customer and act as the principal to the transaction. Determining whether we control the good or service before it is transferred to the customer may require judgment. Disaggregated Revenue We disaggregate revenue from contracts with customers by the reportable segment, products, and services provided. The following presentation depicts the timing, risks, and uncertainty of our revenue streams, which is also in line with how we manage our businesses, assess performance, and determine management compensation. Our disaggregated revenue from continuing operations is as follows (dollars in thousands): For the Year Ended September 30, 2020 Hosting and professional services Product and licensing Maintenance and support Total Healthcare $ 577,787 $ 201,207 $ 136,338 $ 915,332 Enterprise 319,347 89,950 120,380 529,677 Other 28,910 4,970 10 33,890 Total revenues $ 926,044 $ 296,127 $ 256,728 $ 1,478,899 For the Year Ended September 30, 2019 Hosting and professional services Product and licensing Maintenance and support Total Healthcare $ 546,037 $ 246,788 $ 156,905 $ 949,730 Enterprise 316,247 82,073 111,758 510,078 Other 51,359 9,832 272 61,463 Total revenues $ 913,643 $ 338,693 $ 268,935 $ 1,521,271 Hardware revenue comprised approximately $28.0 million of total product and licensing revenue for fiscal year 2020 and $30.0 million for fiscal year 2019. Contract Acquisition Costs We are required to capitalize certain contract acquisition costs under ASC 606. The capitalized costs primarily relate to paid commissions and other direct, incremental costs to acquire customer contracts. In accordance with the practical expedient in ASC 606-10-10-4, we apply a portfolio approach to estimate contract acquisition costs for groups of customer contracts. We elect to apply the practical expedient in ASC 340-40-25-4 and will expense contract acquisition costs as incurred where the expected period of benefit is one year or less. Sales commissions paid on renewal maintenance and support are not commensurate with sales commissions paid on the initial maintenance and support contract. Contract acquisition costs are deferred and amortized on a straight-line basis over the period of benefit, which we have estimated to be between one and five years. The period of benefit was determined based on an average customer contract term, expected contract renewals, changes in technology and our ability to retain customers including canceled contracts. Contract acquisition costs are classified as current or noncurrent assets based on when the expense will be recognized. The current and noncurrent portions of contract acquisition costs are included in Prepaid expenses and other current assets, and Other assets, respectively. As of September 30, 2020, we had $22.5 million of current contract acquisition costs and $54.1 million of noncurrent contract acquisition costs. As of September 30, 2019, we had $19.9 million of current contract acquisition costs and $30.1 million of noncurrent contract acquisition costs. Commission expense is primarily included in Sales and marketing expense on the consolidated statements of operations. We also had amortization expense of $18.5 million and $15.5 million related to contract acquisition costs for the year ended September 30, 2020 and 2019. There was no impairment related to commission costs capitalized. Capitalized Contract Costs We capitalize incremental costs incurred to fulfill our contracts that (1) relate directly to the contract, (2) are expected to generate resources that will be used to satisfy our performance obligation under the contract, and (3) are expected to be recovered through revenue generated under the contract. Our capitalized costs consist primarily of setup costs, such as costs to standup, customize, and develop applications for each customer. These costs are incurred to satisfy our stand-ready obligation to provide access to our connected offerings. The contract costs are expensed to cost of revenue as we satisfy our stand-ready obligation over the contract term, which we estimate to be between one and five years. The contract term estimation was determined based on an average customer contract term, expected contract renewals, changes in technology, and our ability to retain customers including canceled contracts. We classify capitalized contract costs as current or noncurrent based on the timing of when we expect to recognize the expense. The current and noncurrent portions of capitalized contract fulfillment costs are included in Prepaid expenses and other current assets, and Other assets, respectively. At September 30, 2020, we had $18.5 million of short-term contract costs included with Prepaid expenses and other current assets and $32.8 million of long-term costs included within Other assets. As of September 30, 2019, we had $17.2 million of short-term contract costs included with Prepaid expenses and other current assets and $38.5 million of long-term costs included within Other assets. Trade Accounts Receivable and Contract Balances We classify our right to consideration in exchange for deliverables as either a receivable or a contract asset. A receivable is a right to consideration that is unconditional (i.e. only the passage of time is required before payment is due). We present such receivables in Accounts receivable, net in our consolidated balance sheets at their net estimated realizable value. We maintain an allowance for doubtful accounts to provide for the estimated amount of receivables that may not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables and other applicable factors. Our contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. Contract assets include unbilled amounts from long-term contracts when revenue recognized exceeds the amount billed to the customer, and right to payment is not solely subject to the passage of time. The current and noncurrent portions of contract assets are included in Prepaid expenses and other current assets, and Other assets. As of September 30, 2020, we had $49.3 million of current contract assets and $109.9 million of noncurrent contract assets. As of September 30, 2019, we had $58.7 million of current contract assets and $108.7 million of noncurrent contract assets. The table below shows significant changes in contract assets of continuing operations (dollars in thousands): Contract assets Balance September 30, 2019 $ 167,324 Revenues recognized but not billed 286,242 Amounts reclassified to accounts receivable (294,315 ) Balance September 30, 2020 $ 159,251 Our contract liabilities, or Deferred revenue, consist of advance payments and billings in excess of revenues recognized. We classify Deferred revenue as current or noncurrent based on when we expect to recognize the revenues. The table below shows significant changes in Deferred revenue of continuing operations (dollars in thousands): Deferred revenue Balance September 30, 2019 $ 348,006 Amounts bill but not recognized 819,049 Revenue recognized (801,423 ) Balance September 30, 2020 $ 365,632 Remaining Performance Obligations The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied or partially unsatisfied at September 30, 2020 (dollars in thousands): Within One Year Two to Four Years Greater than Four Years Total Total revenue $ 708,343 $ 963,223 $ 62,872 $ 1,734,438

Disposition of Business (Notes)

Disposition of Business (Notes)	12 Months Ended
	Sep. 30, 2020
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Disposition of Businesses Spin-off of Automotive On October 1, 2019, we completed the spin-off of our Automotive business as an independent public company, Cerence, and a pro rata and tax-free distribution to our stockholders of all of the outstanding shares of Cerence owned by Nuance on October 1, 2019. In connection with the spin-off, on September 30, 2019, we sold 1.8% of our equity interest in Cerence to a non-affiliated third party for a total cash consideration of $9.8 million. The difference between the consideration received and the carrying amount of the non-controlling interest was recognized in additional paid-in capital, which was subsequently derecognized as part of the spin- off transaction. Effective as of October 1, 2019, for all periods presented, the results of operations, balance sheets and cash flows of our former Automotive business have been included within discontinued operations. For the year ended September 30, 2020 , we incurred cash payments of $13.3 million related to the separation and spin-off of our Automotive business, which have been presented as operating cash flows from discontinued operations. Sale of Imaging On February 1, 2019, we completed the sale of our Imaging business and received approximately $404.0 million in cash, after estimated transaction expenses. As a result, we recorded a gain of approximately $102.4 million, which has been included within Net income from discontinued operations. The historical results of operations for Imaging and Automotive have been included within discontinued operations in our condensed consolidated financial statements. The following table summarizes the results of the discontinued operations (dollars in thousands): Year Ended September 30, 2020 2019 2018 (ASC 606) (ASC 606) (ASC 605) Major line items constituting net (loss) income of discontinued operations: Revenue $ — $ 369,251 $ 484,061 Cost of revenue — 113,381 130,168 Research and development — 90,810 98,134 Sales and marketing — 57,905 101,755 General and administrative — 4,367 15,965 Amortization of intangible assets — 17,743 25,936 Acquisition-related costs, net — 558 4,091 Restructuring and other related charges 7,386 64,569 10,652 Other — (332 ) 98 (Loss) income from discontinued operations before income taxes (7,386 ) 20,250 97,262 (Benefit) provision for income taxes — (103,387 ) 20,353 Gain on disposition — 102,371 — Net (loss) income from discontinued operations (7,386 ) 226,008 76,909 Supplemental information: Depreciation — 8,204 10,928 Amortization — 28,510 42,591 Stock compensation — 29,060 23,742 Capital expenditures — 5,977 9,331 Payments for business and technology acquisitions, net of cash acquired — — 79,802 The following table summarizes the assets and liabilities of our former Automotive and Imaging reportable segments included within discontinued operations (dollars in thousands) September 30, (ASC 606) Major classes of assets of discontinued operations: Accounts receivable, net $ 67,928 Prepaid expenses and other current assets 23,930 Land, building and equipment, net 20,113 Goodwill 1,115,568 Intangible assets, net 65,561 Other assets 35,366 Total assets classified as held for sale $ 1,328,466 Major classes of liabilities of discontinued operations: Accounts payable $ 14,039 Accrued expenses and other current liabilities 27,429 Deferred revenue 353,700 Other 21,603 Total liabilities classified as held for sale $ 416,771 Other Dispositions

Business Acquisitions

Business Acquisitions	12 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Weighted average life (Years)	Business Acquisitions As part of our business strategy, we have acquired, and may acquire in the future, certain businesses and technologies primarily to expand our products and service offerings. Fiscal Year 2019 In fiscal year 2019 , we completed one acquisition in our Healthcare segment for a total consideration of $19.7 million , including $17.8 million in cash, $1.5 million estimated fair value for future contingent payments, and $0.3 million related to the carrying value of existing warrants. As a result, we recognized goodwill of $8.8 million and other intangible assets of $10.5 million related to technology with a useful life of 5.0 years. The results of operations of the acquired entity has been included within our consolidated results of operations from the acquisition date. The acquisition was not material to our consolidated financial statements. Fiscal Year 2018 In fiscal year 2018 , we completed several acquisitions in our Healthcare segment for a total consideration of $28.5 million , including $26.5 million in cash, and $2.0 million estimated fair value for future contingent payments. As a result, we recognized goodwill of $15.7 million , including immaterial measurement-period adjustments through September 30, 2018 and other intangible assets of $11.2 million , with a weighted average life of 5.8 years . The results of operations of the acquired entities have been included within our consolidated results of operations from the acquisition dates. Such acquisitions were not material, individually or in the aggregate to our consolidated financial statements.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets The changes in the carrying amount of goodwill for our reportable segments for fiscal years 2020 and 2019 were as follows (dollars in thousands): Healthcare Enterprise Other Total Balance as of September 30, 2018 $ 1,430,325 $ 683,347 $ 13,487 $ 2,127,159 Acquisitions 8,785 — — 8,785 Purchase accounting adjustments 113 — — 113 Effect of foreign currency translation (4,079 ) (3,444 ) (638 ) (8,161 ) Balance as of September 30, 2019 1,435,144 679,903 12,849 2,127,896 Purchase accounting adjustments (31 ) — — (31 ) Effect of foreign currency translation 3,063 2,697 87 5,847 Balance as of September 30, 2020 $ 1,438,176 $ 682,600 $ 12,936 $ 2,133,712 Intangible assets consist of the following as of September 30, 2020 and 2019 (dollars in thousands): September 30, 2020 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Life (Years) Customer relationships $ 523,042 $ (360,617 ) $ 162,425 4.4 Technology and patents 205,451 (154,926 ) 50,525 3.1 Trade names, trademarks, and other 28,969 (28,435 ) 534 0.9 Total $ 757,462 $ (543,978 ) $ 213,484 September 30, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Life (Years) Customer relationships $ 500,953 $ (292,127 ) $ 208,826 5.3 Technology and patents 147,394 (69,259 ) 78,135 3.8 Trade names, trademarks, and other 28,961 (24,551 ) 4,410 1.2 Total $ 677,308 $ (385,937 ) $ 291,371 Amortization expense for acquired technology and patents is included in the cost of revenue in the accompanying statements of operations and was $27.8 million , $27.4 million and $40.2 million in fiscal years 2020 , 2019 and 2018 , respectively. Amortization expense for customer relationships, trade names, trademarks, and other, and non-competition agreements is included in operating expenses and was $50.9 million , $54.2 million and $65.2 million in fiscal years 2020 , 2019 and 2018 , respectively. Estimated amortization expense for each of the five succeeding years as of September 30, 2020 , is as follows (dollars in thousands): Year Ending September 30, Cost of Revenue Other Operating Expenses Total 2021 $ 16,994 $ 43,036 $ 60,030 2022 16,272 39,788 56,060 2023 12,323 33,680 46,003 2024 4,936 20,074 25,010 2025 — 19,032 19,032 Thereafter — 7,349 7,349 Total $ 50,525 $ 162,959 $ 213,484 Fiscal Year 2018 Goodwill and Intangible Assets Impairment Effective the second quarter of fiscal year 2018, our Automotive business, which was previously included within our former Mobile segment, became a standalone operating segment. As a result of the reorganization, the former Mobile reporting unit was separated into three discrete lines of business comprised of Automotive, Dragon TV, and Devices. Dragon TV was merged within our Enterprise segment, and Devices was included within Other segment. We assigned $1,080.5 million , $12.0 million , and $36.0 million of goodwill to Automotive, Dragon TV and Devices, respectively, based on their relative fair values as of March 31, 2018, and assessed the assigned goodwill for impairment by comparing each component’s fair value to its carrying amount. As a result, we recorded a $35.1 million goodwill impairment for devices during the second quarter of fiscal year 2018. Also, during the second quarter of fiscal year 2018, our Subscriber Revenue Services ("SRS") reporting unit, originally included within our Mobile operating segment, recorded significantly lower revenue and profitability due to recent market disruptions in certain markets that we serve. We concluded that these financial results coupled with the rapid market shifts being experienced in the industry were factors that represented impairment indicators, triggering a review of goodwill and indefinite-lived intangible assets for impairment during the second quarter of fiscal year 2018. As a result, we recorded a goodwill impairment charge of $102.8 million related to SRS for the second quarter of fiscal year 2018. The assessment did not result in any impairment charge of other intangible assets. During the fourth quarter of fiscal year 2018, in connection with our strategic business review announced in our earnings release issued on May 9, 2018, we restructured our SRS business by separating the Voicemail-to-Text business, which continued to operate as part of the Other Segment, and commenced a wind-down of our SRS Mobile Operator Services in India and Brazil, and our Devices businesses. The wind-down decision resulted in significantly lower estimated future cash flows over a considerably shorter time horizon, which triggered a review of goodwill and long-lived asset groups for impairment. As a result of the impairment review, we recorded an additional $15.0 million impairment charge for Devices for the fourth quarter of fiscal year 2018, including $7.6 million related to acquired trade names and customer relationships, $0.8 million related to acquired technology assets, $6.2 million related to fixed assets, and $0.4 million related to its remaining goodwill; we also recorded a $25.1 million impairment charge for our Mobile Operator Services business for the fourth quarter of fiscal year 2018, including $12.9 million related to acquired trade names and customer relationships, $7.9 million related to acquired technology assets, $0.9 million related to fixed assets, and $3.4 million related to goodwill.

Accounts Receivable

Accounts Receivable	12 Months Ended
	Sep. 30, 2020
Receivables [Abstract]
Accounts Receivable	Accounts Receivable , Net Accounts receivable, net consisted of the following (dollars in thousands): September 30, 2020 September 30, 2019 (ASC 606) (ASC 606) Accounts receivable, gross $ 215,347 $ 255,061 Less: allowance for doubtful accounts (11,115 ) (9,797 ) Less: allowance for sales returns (3,656 ) (4,591 ) Accounts receivable, net $ 200,576 $ 240,673

Land, Building and Equipment, N

Land, Building and Equipment, Net	12 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Land, Building and Equipment, Net	Land, Buildings and Equipment, Net Land, building and equipment, net consisted of the following (dollars in thousands): Useful Life (In Years) September 30, 2020 September 30, 2019 Land — $ 2,400 $ 2,400 Building 30 6,741 6,696 Machinery and equipment 3-5 156,454 159,681 Computers, software and equipment 3-5 157,000 131,012 Leasehold improvements 2-15 32,988 26,244 Furniture and fixtures 5-7 11,217 14,455 Construction in progress — 41,694 20,708 Subtotal 408,494 361,196 Less: accumulated depreciation (265,066 ) (239,993 ) Land, building and equipment, net $ 143,428 $ 121,203 Depreciation expense for fiscal years 2020 , 2019 and 2018 was $37.8 million , $47.4 million and $51.4 million , respectively, which included amortization expense of $5.2 million , $4.1 million and $7.0 million , respectively, for internally developed software costs.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Sep. 30, 2020
Accrued Liabilities, Current [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (dollars in thousands): September 30, 2020 September 30, 2019 Compensation $ 117,963 $ 119,412 Accrued interest payable 13,484 19,302 Cost of revenue related liabilities 29,953 58,012 Consulting and professional fees 10,857 20,401 Deferred rent liabilities — 2,503 Sales and marketing incentives 2,021 2,692 Sales and other taxes payable 6,339 8,089 ASC 842 operating lease obligations 28,273 — Other 4,374 19,159 Total $ 213,264 $ 249,570

Credit Facilities and Debt

Credit Facilities and Debt	12 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Credit Facilities and Debt	At September 30, 2020 and 2019 , we had the following borrowing obligations (dollars in thousands): September 30, 2020 September 30, 2019 5.625% Senior Notes due 2026, net of deferred issuance costs of $3.9 million and $4.5 million, respectively. Effective interest rate 5.625%. $ 496,148 $ 495,518 6.000% Senior Notes due 2024, net of deferred issuance costs of $1.5 million. Effective interest rate 6.000%. — 298,529 1.00% Convertible Debentures due 2035, net of unamortized discount of $64.8 million and $91.6 million, respectively, and deferred issuance costs of $2.9 million and $4.3 million, respectively. Effective interest rate 5.622%. 608,767 580,639 2.75% Convertible Debentures due 2031. Effective interest rate 7.432%. — 46,568 1.25% Convertible Debentures due 2025, net of unamortized discount of $45.2 million and $71.6 million, respectively, and deferred issuance costs of $1.9 million and $3.1 million, respectively. Effective interest rate 5.578%. 215,582 275,257 1.50% Convertible Debentures due 2035, net of unamortized discount of $10.4 million and $22.7 million, respectively, and deferred issuance costs of $0.3 million and $0.8 million, respectively. Effective interest rate 5.394%. 216,627 240,406 Deferred issuance costs related to our Revolving Credit Facility. (451 ) (511 ) Total debt 1,536,673 1,936,406 Less: current portion (a) (432,209 ) (1,142,870 ) Total long-term debt $ 1,104,464 $ 793,536 (a) As of September 30, 2020, the holders had the right to convert all or any portion of the 1.25% 2025 Debentures and 1.5% 2035 Debentures between October 1, 2020 and December 31, 2020. As a result, the net carrying amounts of our convertible notes were included in current liabilities as of September 30, 2020. During fiscal year 2019, in connection with the spin-off of our Automotive business, we notified holders on September 5, 2019, that they had the right to convert all or any portion of their debentures until the close of business on October 1, 2019. As of September 30, 2019, the net carrying amounts of our convertible notes were included within the current portion of long-term debt. Upon the conclusion of the conversion period on October 1, 2019, none of the holders exercised their right to convert. As a result, the net carrying amounts of the convertible notes were reclassified back to long-term debt in the first quarter of fiscal year 2020. The following table summarizes the maturities of our borrowing obligations as of September 30, 2020 (dollars in thousands): Fiscal Year Convertible Debentures (1) Senior Notes Total 2021 $ 490,051 $ — $ 490,051 2022 — — — 2023 676,488 — 676,488 2024 — — — 2025 — — — Thereafter — 500,000 500,000 Total before unamortized discount 1,166,539 500,000 1,666,539 Less: unamortized discount and issuance costs (125,563 ) (4,303 ) (129,866 ) Total debt $ 1,040,976 $ 495,697 $ 1,536,673 (1) The repayment schedule above assumes that payment is due on the first contractual redemption date after September 30, 2020 . As more fully described below, as of September 30, 2020 , the holders had the right to convert all or any portion of the 1.25% 2025 Debentures and 1.5% 2035 Debentures between October 1, 2020 and December 31, 2020. As a result, the net carrying amounts of these two convertible notes were included in current liabilities as of September 30, 2020 . 5.625% Senior Notes due 2026 In December 2016, we issued $500.0 million aggregate principal amount of 5.625% Senior Notes due on December 15, 2026 (the "2026 Senior Notes") in a private placement. The proceeds from the 2026 Senior Notes were approximately $495.0 million , net of issuance costs, and we used the proceeds to repurchase a portion of our then outstanding 5.375% Senior Notes due in 2020. The 2026 Senior Notes bear interest at 5.625% per year, payable in cash semi-annually in arrears. The 2026 Senior Notes are unsecured senior obligations and are guaranteed on an unsecured senior basis by certain of our domestic subsidiaries ("Subsidiary Guarantors"). The 2026 Senior Notes and the guarantees rank equally in right of payment with all of our and the Subsidiary Guarantors’ existing and future unsecured senior debt and rank senior in right of payment to all of our and the Subsidiary Guarantors’ future unsecured subordinated debt. The 2026 Senior Notes and guarantees effectively rank junior to all our secured debt and that of the Subsidiary Guarantors to the extent of the value of the collateral securing such debt and to all liabilities, including trade payables, of our subsidiaries that have not guaranteed the 2026 Senior Notes. At any time before December 15, 2021, we may redeem all or a portion of the 2026 Senior Notes at a redemption price equal to 100% of the aggregate principal amount of the 2026 Senior Notes to be redeemed, plus a “make-whole” premium and accrued and unpaid interest to, but excluding, the redemption date. At any time on or after December 15, 2021, we may redeem all or a portion of the 2026 Senior Notes at certain redemption prices expressed as percentages of the principal amount, plus accrued and unpaid interest to, but excluding, the redemption date. At any time and from time to time before December 15, 2021, we may redeem up to 35% of the aggregate outstanding principal amount of the 2026 Senior Notes with the net cash proceeds received by us from certain equity offerings at a price equal to 105.625% of the aggregate principal amount, plus accrued and unpaid interest to, but excluding, the redemption date, provided that the redemption occurs no later than 120 days after the closing of the related equity offering, and at least 50% of the original aggregate principal amount of the 2026 Senior Notes remains outstanding immediately thereafter. Upon the occurrence of certain asset sales or a change in control, we must offer to repurchase the 2026 Senior Notes at a price equal to 100% in the case of an asset sale, or 101% in the case of a change of control, of the principal amount plus accrued and unpaid interest to, but excluding, the repurchase date. 6.0% Senior Notes due 2024 In June 2016 , we issued $300.0 million aggregate principal amount of 6.0% Senior Notes due on July 1, 2024 (the "2024 Senior Notes") in a private placement. The proceeds from the 2024 Senior Notes were approximately $297.5 million , net of issuance costs. The 2024 Senior Notes bear interest at 6.0% per year, payable in cash semi-annually in arrears. On October 1, 2019, we redeemed all the $300.0 million outstanding principal amount of the 2024 Senior Notes for $313.5 million , plus accrued and unpaid interest of $4.5 million . As a result of the redemption, we recorded a $15.0 million loss on extinguishment of debt for the first quarter of fiscal year 2020, including a $13.5 million redemption premium and a $1.5 million write-off of unamortized debt issuance costs. 1.0% Convertible Debentures due 2035 In December 2015, we issued $676.5 million in aggregate principal amount of 1.0% Senior Convertible Debentures due in 2035 (the “1.0% 2035 Debentures”) in a private placement. Total proceeds were $663.8 million , net of issuance costs, and we used a portion to repurchase $38.3 million in aggregate principal on our 2.75% Senior Convertible Debentures due in 2031 (the "2.75% 2031 Debentures") and to repay the aggregate principal balance of $472.5 million on our term loan under the amended and restated credit agreement. The 1.0% 2035 Debentures bear interest at 1.0% per year, payable in cash semi-annually in arrears. In addition to ordinary interest and default additional interest, beginning with the semi-annual interest period commencing on December 15, 2022, contingent interest will accrue during any regular semi-annual interest period where the average trading price of our 1.0% 2035 Debentures for the ten trading day period immediately preceding the first day of such semi-annual period is greater than or equal to $1,200 per $1,000 principal amount of our 1.0% 2035 Debentures, in which case, contingent interest will accrue at a rate of 0.50% per annum of such average trading price. The 1.0% 2035 Debentures mature on December 15, 2035, subject to the right of the holders to require us to redeem the 1.0% 2035 Debentures on December 15, 2022, 2027, or 2032. The 1.0% 2035 Debentures are general senior unsecured obligations and rank equally in right of payment with all of our existing and future unsecured, unsubordinated indebtedness and senior in right of payment to any indebtedness that is contractually subordinated to the 1.0% 2035 Debentures. The 1.0% 2035 Debentures will be effectively subordinated to indebtedness and other liabilities of our subsidiaries. We account separately for the liability and equity components of the 1.0% 2035 Debentures in accordance with authoritative guidance for convertible debt instruments that may be settled in cash upon conversion. The guidance requires the carrying amount of the liability component to be estimated by measuring the fair value of a similar liability that does not have an associated conversion feature and record the remainder in stockholders’ equity. At issuance, we allocated $495.4 million to long-term debt, and $181.1 million has been recorded as additional paid-in capital, which is being amortized to interest expense using the effective interest rate method through December 2022. If converted, the principal amount of the 1.0% 2035 Debentures is payable in cash and any amounts payable in excess of the principal amount will (based on an initial conversion rate, which represents an initial conversion price of approximately $24.12 per share, subject to adjustment) be paid in cash or shares of our common stock, at our election. Conversion is only allowed in the following circumstances and to the following extent: (i) prior to June 15, 2035, on any date during any fiscal quarter (and only during such fiscal quarter) if the closing sale price of our common stock was more than 130% of the then current conversion price for at least 20 trading days in the period of the 30 consecutive trading days ending on the last trading day of the previous fiscal quarter; (ii) during the five consecutive business-day period following any five consecutive trading-day period in which the trading price for $1,000 principal amount of the 1.0% 2035 Debentures for each day during such five trading-day period was less than 98% of the closing sale price of our common stock multiplied by the then current conversion rate; (iii) upon the occurrence of specified corporate transactions, as described in the indenture for the 1.0% 2035 Debentures; or (iv) at the option of the holder at any time on or after June 15, 2035. Additionally, we may redeem the 1.0% 2035 Debentures, in whole or in part, on or after December 20, 2022 for cash at a price equal to 100% of the principal amount of the 1.0% 2035 Debentures to be purchased plus any accrued and unpaid interest, including any additional interest to, but excluding, the repurchase date. Each holder shall have the right, at such holder’s option, to require us to repurchase all or any portion of the 1.0% 2035 Debentures held by such holder on December 15, 2022, December 15, 2027, or December 15, 2032 at par plus accrued and unpaid interest. If we undergo a fundamental change or non-stock change of control (as described in the indenture for the 1.0% 2035 Debentures) prior to maturity, holders will have the option to require us to repurchase all or any portion of their debentures for cash at a price equal to 100% of the principal amount of the 1.0% 2035 Debentures to be purchased plus any accrued and unpaid interest. In accordance with the terms of the indentures governing the debentures and due to the completion of the spin-off of our Automotive business, the conversion ratio of the 1.0% 2035 Debentures has been adjusted from 36.7360 to 41.4576 shares per $1,000 principal amount. As of September 30, 2020 , none of the conversion criteria were met for the 1.0% 2035 Debentures. If the conversion criteria were met, we could be required to repay all or some of the aggregate principal amount in cash prior to the maturity date. As of September 30, 2020 , the if-converted value of the 1.0% 2035 Debentures exceeded its principal amount by $254.3 million . 2.75% Convertible Debentures due 2031 On October 24, 2011 , we sold $690.0 million of the 2.75% 2031 Debentures in a private placement. Total proceeds, net of issuance costs, were $676.1 million . The 2.75% 2031 Debentures bear interest at 2.75% per year, payable in cash semi-annually in arrears. The 2.75% 2031 Debentures mature on November 1, 2031 , subject to the right of the holders to require us to redeem the 2.75% 2031 Debentures on November 1, 2021 and 2026 . The 2.75% 2031 Debentures are general senior unsecured obligations and rank equally in right of payment with all of our existing and future unsecured, unsubordinated indebtedness and senior in right of payment to any indebtedness that is contractually subordinated to the 2.75% 2031 Debentures. The 2.75% 2031 Debentures will be effectively subordinated to indebtedness and other liabilities of our subsidiaries. At issuance, we allocated $533.6 million to long-term debt, and $156.4 million has been recorded as additional paid-in capital, which was amortized to interest expense using the effective interest rate method through November 2017. In June 2015, we entered into separate privately negotiated agreements with certain holders of our 2.75% 2031 Debentures to exchange, in a private placement, $256.2 million in aggregate principal amount of our 2031 Debentures for approximately $263.9 million in aggregate principal amount of our 1.5% Senior Convertible Debentures due in 2035 (the "1.5% 2035 Debenture"). In December 2015, we entered into separate privately negotiated agreements with certain holders of our 2.75% 2031 Debentures to repurchase $38.3 million in aggregate principal with proceeds received from the issuance of our 1.0% 2035 Debentures. Following this activity, $395.5 million in aggregate principal amount of our 2.75% 2031 Debentures remain outstanding. The aggregate debt discount was amortized to interest expense using the effective interest rate method through November 2017 . In November 2017, holders of approximately $331.2 million in aggregate principal amount of the outstanding 2.75% 2031 Debentures exercised their right to require us to repurchase such debentures. Following the repurchase, $46.6 million in aggregate principal amount of the 2.75% 2031 Debentures remains outstanding. We have the right to call for redemption of some or all of the remaining outstanding 2.75% 2031 Debentures. In March 2020, we redeemed the remaining $46.6 million outstanding amount of the 2.75% Convertible Debentures at par. The issuance costs and discount had been fully amortized. No gain or loss was recognized for the redemption. 1.25% Convertible Debentures due 2025 In March 2017, we issued $350.0 million in aggregate principal amount of 1.25% Senior Convertible Debentures due in 2025 (the “1.25% 2025 Debentures”) in a private placement. The proceeds were approximately $343.6 million , net of issuance costs. We used a portion of the proceeds to repurchase 5.8 million shares of our common stock for $99.1 million and $17.8 million in aggregate principal on our 2.75% 2031 Debentures. The 1.25% 2025 Debentures bear interest at 1.25% per year, payable in cash semi-annually in arrears, beginning on October 1, 2017. The 1.25% 2025 Debentures mature on April 1, 2025. The 1.25% 2025 Debentures are general senior unsecured obligations and rank equally in right of payment with all of our existing and future unsecured, unsubordinated indebtedness and senior in right of payment to any indebtedness that is contractually subordinated to the 1.25% 2025 Debentures. The 1.25% 2025 Debentures will be effectively subordinated to indebtedness and other liabilities of our subsidiaries. We account separately for the liability and equity components of the 1.25% 2025 Debentures in accordance with authoritative guidance for convertible debt instruments that may be settled in cash upon conversion. The guidance requires the carrying amount of the liability component to be estimated by measuring the fair value of a similar liability that does not have an associated conversion feature and record the remainder in stockholders’ equity. At issuance, we allocated $252.1 million to long-term debt, and $97.9 million has been recorded as additional paid-in capital, which is being amortized to interest expense using the effective interest rate method through April 1, 2025. If converted, the principal amount of the 1.25% 2025 Debentures is payable in cash and any amounts payable in excess of the principal amount will (based on an initial conversion rate, which represents a conversion price of approximately $19.69 per share, subject to adjustment under certain circumstances) be paid in cash or shares of our common stock, at our election. Conversion is only allowed in the following circumstances and to the following extent: (i) prior to October 1, 2024, on any date during any fiscal quarter (and only during such fiscal quarter) if the closing sale price of our common stock was more than 130% of the then current conversion price for at least 20 trading days in the period of the 30 consecutive trading days ending on the last trading day of the previous fiscal quarter; (ii) at any time on or after October 1, 2024, (iii) during the five consecutive business-day period immediately following any five consecutive trading-day period in which the trading price for $1,000 principal amount of the 1.25% 2025 Debentures for each day during such five trading-day period was less than 98% of the closing sale price of our common stock multiplied by the then current conversion rate; or (iv) upon the occurrence of specified corporate transactions, as described in the indenture for the 1.25% 2025 Debentures. We may not redeem the 1.25% 2025 Debentures prior to the maturity date. If we undergo a fundamental change or non-stock change of control (as described in the indenture for the 1.25% 2025 Debentures) prior to maturity, holders will have the option to require us to repurchase all or any portion of their debentures for cash at a price equal to 100% of the principal amount of the 1.25% 2025 Debentures to be purchased plus any accrued and unpaid interest. In accordance with the terms of the indentures governing the debentures and due to the completion of the spin-off of our Automotive business, the conversion ratio of the 1.25% 2025 Debentures has been adjusted to from 45.0106 to 50.7957 shares per $1,000 principal amount. During the second quarter of fiscal year 2020, we repurchased $87.3 million notional amount of our 1.25% 2025 Debentures for $112.3 million , of which we allocated $72.8 million to debt and $39.5 million to equity based upon ASC 470-20. Also, in connection with the repurchases, we wrote off $16.7 million unamortized discount and $0.7 million unamortized costs. As a result, we recorded a $2.8 million loss associated with the repurchases. Following the repurchases, $262.7 million in aggregate principal amount of the 1.25% 2025 Debentures remain outstanding. On September 30, 2020 , we notified the debt trustee that the holders had the right to convert all or any portion of their debentures at the aforementioned conversion ratio beginning October 1, 2020 through December 31, 2020. The 1.25% 2025 Debentures became convertible because Nuance’s common stock price exceeded the conversion threshold price (130% of the applicable conversion price per share) for at least 20 trading days during the 30 consecutive trading days ending September 30, 2020 . As of September 30, 2020 , the net carrying amount of the 1.25% 2025 Debentures was included within the current portion of long-term debt. As of September 30, 2020 , the if-converted value of the 1.25% 2025 Debentures exceeded its principal amount by $180.2 million . 1.50% Convertible Debentures due 2035 In June 2015, we issued $263.9 million in aggregate principal amount of 1.5% Senior Convertible Debentures due in 2035 in exchange for $256.2 million in aggregate principal amount of our 2.75% 2031 Debentures. Total proceeds, net of issuance costs, were $253.2 million . The 1.5% 2035 Debentures were issued at 97.09% of the principal amount, which resulted in a discount of $7.7 million . The 1.5% 2035 Debentures bear interest at 1.5% per year, payable in cash semi-annually in arrears. In addition to ordinary interest and default additional interest, beginning with the semi-annual interest period commencing on November 1, 2021, contingent interest will accrue during any regular semi-annual interest period where the average trading price of our 1.5% 2035 Debentures for the ten trading day period immediately preceding the first day of such semi-annual period is greater than or equal to $1,200 per $1,000 principal amount of our 1.5% 2035 Debentures, in which case, contingent interest will accrue at a rate of 0.50% per annum of such average trading price. The 1.5% 2035 Debentures mature on November 1, 2035, subject to the right of the holders to require us to redeem the 1.5% 2035 Debentures on November 1, 2021, 2026, or 2031. The 1.5% 2035 Debentures are general senior unsecured obligations and rank equally in right of payment with all of our existing and future unsecured, unsubordinated indebtedness and senior in right of payment to any indebtedness that is contractually subordinated to the 1.5% 2035 Debentures. The 1.5% 2035 Debentures will be effectively subordinated to indebtedness and other liabilities of our subsidiaries. We account separately for the liability and equity components of the 1.5% 2035 Debentures in accordance with authoritative guidance for convertible debt instruments that may be settled in cash upon conversion. At issuance, we allocated $208.6 million to long-term debt, and $55.3 million has been recorded as additional paid-in capital, which is being amortized to interest expense using the effective interest rate method through November 2021. If converted, the principal amount of the 1.5% 2035 Debentures is payable in cash and any amounts payable in excess of the principal amount, will (based on an initial conversion rate, which represents an initial conversion price of approximately $20.61 per share, subject to adjustment) be paid in cash or shares of our common stock, at our election. Conversion is only allowed in the following circumstances and to the following extent: (i) prior to May 1, 2035, on any date during any fiscal quarter beginning after September 30, 2015 (and only during such fiscal quarter) if the closing sale price of our common stock was more than 130% of the then current conversion price for at least 20 trading days in the period of the 30 consecutive trading days ending on the last trading day of the previous fiscal quarter; (ii) during the five consecutive business-day period following any five consecutive trading-day period in which the trading price for $1,000 principal amount of the 1.5% 2035 Debentures for each day during such five trading-day period was less than 98% of the closing sale price of our common stock multiplied by the then current conversion rate; (iii) upon the occurrence of specified corporate transactions, as described in the indenture for the 1.5% 2035 Debentures; or (iv) at the option of the holder at any time on or after May 1, 2035. Additionally, we may redeem the 1.5% 2035 Debentures, in whole or in part, on or after November 5, 2021 for cash at a price equal to 100% of the principal amount of the 1.5% 2035 Debentures to be purchased plus any accrued and unpaid interest, including any additional interest to, but excluding, the repurchase date. Each holder shall have the right, at such holder’s option, to require us to repurchase all or any portion of the 1.5% 2035 Debentures held by such holder on November 1, 2021, November 1, 2026, or November 1, 2031 at par plus accrued and unpaid interest. If we undergo a fundamental change (as described in the indenture for the 1.5% 2035 Debentures) prior to maturity, holders will have the option to require us to repurchase all or any portion of their debentures for cash at a price equal to 100% of the principal amount of the 1.5% 2035 Debentures to be purchased plus any accrued and unpaid interest. In accordance with the terms of the indentures governing the debentures and due to the completion of the spin-off of our Automotive business, the conversion ratio of the 1.5% 2035 Debentures has been adjusted from 42.9978 to 48.5216 shares per $1,000 principal amount. During the second quarter of fiscal year 2020, we repurchased $36.5 million notional amount of 1.5% 2035 Debentures for $41.3 million , of which we allocated $34.7 million to debt and $6.6 million to equity based upon ASC 470-20. Also, in connection with the repurchases, we wrote off $2.5 million unamortized discount and $0.1 million unamortized costs. As a result, we recorded a $0.8 million loss associated with the repurchases. Following the repurchases, $227.4 million in aggregate principal amount of the 1.5% 2035 Debentures remain outstanding. On September 30, 2020 , we notified the debt trustee that the holders had the right to convert all or any portion of their debentures at the aforementioned conversion ratio beginning October 1, 2020 through December 31, 2020. The 1.5% 2035 Debentures became convertible because Nuance’s common stock price exceeded the conversion threshold price (130% of the applicable conversion price per share) for at least 20 trading days during the 30 consecutive trading days ending September 30, 2020 . As of September 30, 2020 , the net carrying amount of the 1.5% 2035 Debentures was included within the current portion of long-term debt. As of September 30, 2020 , the if-converted value of the 1.5% 2035 Debentures exceeded its principal amount by $138.8 million . Revolving Credit Facility Our revolving credit agreement (the “Revolving Credit Agreement”) expires on April 15, 2022. On July 31, 2020, we amended the Revolving Credit Agreement to, among other things, extend the expiration from April 15, 2021 to April 15, 2022, and allow the administration agent and Nuance to agree on a new benchmark rate in lieu of LIBOR. The Revolving Credit Agreement provides for aggregate borrowing commitments of $242.5 million (the "Revolving Credit Facility"), including the revolving facility loans, the swingline loans and issuance of letters of credit. The borrowing outstanding under the Revolving Credit Facility bears interest at either (i) LIBOR plus an applicable margin of 1.50% or 1.75% , or (ii) the alternative base rate plus an applicable margin of 0.50% or 0.75% . The Revolving Credit Facility is secured by substantially all our assets. The Revolving Credit Agreement contains customary affirmative and negative covenants and conditions to borrowing, as well as customary events of default. At any time that there are any outstanding borrowings (excluding up to $25,000,000 of issued and undrawn Letters of Credit) under the Revolving Credit Facility, we are required to maintain a Consolidated Senior Secured Leverage Ratio (as defined in the Revolving Credit Agreement) not exceeding 4.00 to 1.00. We were in compliance with all the debt covenants as of September 30, 2020 . On March 24, 2020, we borrowed $230.0 million under our revolving credit facility at an effective interest rate of 2.68% per annum, which was fully repaid on June 26, 2020. As of September 30, 2020 , after taking into account the outstanding letters of credit of $2.4 million , we had $240.1 million

Financial Instruments and Hedgi

Financial Instruments and Hedging Activities	12 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments and Hedging Activities	Financial Instruments and Hedging Activities Derivatives not Designated as Hedges Forward Currency Contracts We have operations in a number of international locations, including certain developing markets where currency exchange rates can be volatile. We utilize foreign currency forward contracts to mitigate the risks associated with changes in foreign currency exchange rates so that our exposure to foreign currencies will be mitigated or offset by the gains or losses on the foreign currency forward contracts. Generally, we enter into such contracts for less than 90 days and have no cash requirements until maturity. As of September 30, 2020 and 2019 , we had outstanding contracts with a total notional value of $40.7 million and $189.6 million , respectively. We did not designate any forward contracts as hedging instruments for fiscal years 2020 , 2019 and 2018 . Therefore, changes in fair value of foreign currency forward contracts were recognized within other expense, net in our consolidated statements of operations. The cash flows related to the settlement of forward contracts not designated as hedging instruments are included in cash flows from investing activities within our consolidated statement of cash flows. A summary of our derivative instruments is as follows (dollars in thousands): Fair Value Derivatives Not Designated as Hedges: Balance Sheet Classification September 30, 2020 September 30, 2019 Foreign currency forward contracts Prepaid expenses and other current assets $ 109 $ 597 Foreign currency forward contracts Accrued expenses and other current liabilities $ (92 ) $ (327 ) A summary of income (loss) related to foreign currency forward contracts for the year ended September 30, 2020 is as follows (dollars in thousands): Income Statement Classification Income (loss) recognized Year Ended September 30, Derivatives Not Designated as Hedges: 2020 2019 2018 Foreign currency forward contracts Other income (expense), net $ 379 $ 1,816 $ (3,616 )

Fair Value Measures

Fair Value Measures	12 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measures	Fair Value Measures Fair value is defined as the price that would be received to sell an asset, or paid to transfer a liability, in an orderly transaction between market participants at the measurement date. Valuation techniques must maximize the use of observable inputs and minimize the use of unobservable inputs. When determining the fair value measurements for assets and liabilities required to be recorded at fair value, we consider the principal or most advantageous market in which we would transact and consider assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions, and risk of nonperformance. The determination of the applicable level within the hierarchy of a particular financial asset or liability depends on the lowest level of inputs that are significant to the fair value measurement as of the measurement date as follows: • Level 1: Quoted prices for identical assets or liabilities in active markets. • Level 2: Observable inputs other than those described as Level 1. • Level 3: Unobservable inputs that are supportable by little or no market activities and are based on significant assumptions and estimates. Assets and liabilities measured at fair value on a recurring basis at September 30, 2020 and 2019 consisted of (dollars in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total Assets: Money market funds (a) $ 182,645 $ — $ — $ 182,645 Time deposits (b) — 95,180 — 95,180 Commercial paper, $33,265 at cost (b) — 33,290 — 33,290 Corporate notes and bonds, $15,460 at cost (b) — 15,480 — 15,480 Foreign currency exchange contracts (b) — 109 — 109 Total assets at fair value $ 182,645 $ 144,059 $ — $ 326,704 Liabilities: Foreign currency exchange contracts (b) $ — $ (92 ) $ — $ (92 ) Contingent acquisition payments (c) — — (1,796 ) (1,796 ) Total liabilities at fair value $ — $ (92 ) $ (1,796 ) $ (1,888 ) September 30, 2019 Level 1 Level 2 Level 3 Total Assets: Money market funds (a) $ 217,861 $ — $ — $ 217,861 Time deposits (b) — 115,913 — 115,913 Commercial paper, $77,089 at cost (b) — 77,494 — 77,494 Corporate notes and bonds, $37,504 at cost (b) — 37,566 — 37,566 Foreign currency exchange contracts (b) — 597 — 597 Total assets at fair value $ 217,861 $ 231,570 $ — $ 449,431 Liabilities: Foreign currency exchange contracts (b) $ — $ (327 ) $ — $ (327 ) Contingent acquisition payments (c) — — (2,550 ) (2,550 ) Total liabilities at fair value $ — $ (327 ) $ (2,550 ) $ (2,877 ) (a) Money market funds and time deposits with original maturity of 90 days or less are included within cash and cash equivalents in the consolidated balance sheets and are valued at quoted market prices in active markets. (b) Time deposits, commercial paper, corporate notes and bonds, and foreign currency exchange contracts are recorded at fair market values, which are determined based on the most recent observable inputs for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active or are directly or indirectly observable. Time deposits are generally for terms of one year or less. Commercial paper and corporate notes and bonds generally mature within three years and had a weighted average maturity of 0.31 years as of September 30, 2020 and 0.53 years as of September 30, 2019 . (c) The fair values of our contingent consideration arrangements were determined using either the option pricing model with Monte Carlo simulation or the probability-weighted discounted cash flow method. The estimated fair value of our long-term debt approximated $2,355.5 million (face value $1,666.5 million ) as of September 30, 2020 and $2,143.4 million (face value $2,137.0 million ) as of September 30, 2019 , based on Level 2 measurements. The fair value of each borrowing was estimated using the average of the bid and ask trading quotes at the end of the reporting periods. There was no balance outstanding under our revolving credit agreement as of September 30, 2019 and 2020. Additionally, contingent acquisition payments are recorded at fair values upon the acquisition and are remeasured in subsequent reporting periods with the changes in fair values recorded within acquisition-related costs, net. Such payments are contingent upon the achievement of specified performance targets and are valued using the option pricing model with Monte Carlo simulation or the probability-weighted discounted cash flow model (Level 3 measurement). The following table provides a summary of changes in fair value of our Level 3 financial instruments for the years ended September 30, 2020 and 2019 (dollars in thousands): Amount Balance as of September 30, 2018 $ 4,000 Earn-out liability established at time of acquisition 1,500 Payments and foreign currency translation (2,550 ) Adjustments to fair value included in acquisition-related costs, net (400 ) Balance as of September 30, 2019 2,550 Payments and foreign currency translation (4 ) Adjustments to fair value included in acquisition-related costs, net (750 ) Balance as of September 30, 2020 $ 1,796 Contingent acquisition payment liabilities are scheduled to be paid in periods through fiscal year 2021 . As of September 30, 2020 , we could be required to pay up to $3.0 million if the specified performance targets are achieved.

Restructuring and Other Charges

Restructuring and Other Charges, Net	12 Months Ended
	Sep. 30, 2020
Restructuring and Related Activities [Abstract]
Restructuring and Other Charges, net	The components of restructuring and other charges, net are as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Personnel $ 5,305 $ 14,212 $ 27,360 Facilities 5,531 2,225 3,868 Total restructuring charges 10,836 16,437 31,228 Other charges 6,844 12,710 21,618 Total restructuring and other charges, net $ 17,680 $ 29,147 $ 52,846 The following table represents the roll forward of restructuring liabilities for fiscal years 2020 , 2019 and 2018 (dollars in thousands): Personnel Facilities Total Balance at September 30, 2017 $ 1,509 $ 8,159 $ 9,668 Restructuring charges, net 27,360 3,868 31,228 Non-cash adjustment — (998 ) (998 ) Cash payments (20,534 ) (4,535 ) (25,069 ) Balance at September 30, 2018 8,335 6,494 14,829 Restructuring charges, net 14,212 2,225 16,437 Non-cash adjustment — (102 ) (102 ) Cash payments (18,960 ) (4,995 ) (23,955 ) Balance at September 30, 2019 3,587 3,622 7,209 ASC 842 implementation (a) — 11,674 11,674 Restructuring charges, net 5,305 5,531 10,836 Non-cash adjustment — 1,052 1,052 Cash payments (7,649 ) (6,266 ) (13,915 ) Balance at September 30, 2020 $ 1,243 $ 15,613 $ 16,856 (a) The amount represents a reclassification of estimated sublease income from restructuring accrual to reduce the costs of right-of-use assets upon the adoption of ASC 842 on October 1, 2019. The table below presents the Restructuring and other charges, net associated with each segment, but excluded from calculation of each segment's profit (dollars in thousands): Personnel Facilities Total Restructuring Other Charges Total Fiscal Year 2020 Healthcare $ 1,953 $ 2,819 $ 4,772 $ — $ 4,772 Enterprise 1,417 1,998 3,415 — 3,415 Other — (63 ) (63 ) — (63 ) Corporate 1,935 777 2,712 6,844 9,556 Total fiscal year 2020 $ 5,305 $ 5,531 $ 10,836 $ 6,844 $ 17,680 Fiscal Year 2019 Healthcare $ 4,679 $ 191 $ 4,870 $ — $ 4,870 Enterprise 5,037 933 5,970 — 5,970 Other 1,457 337 1,794 3,306 5,100 Corporate 3,039 764 3,803 9,404 13,207 Total fiscal year 2019 $ 14,212 $ 2,225 $ 16,437 $ 12,710 $ 29,147 Fiscal Year 2018 Healthcare $ 11,563 $ 25 $ 11,588 $ — $ 11,588 Enterprise 4,217 2,243 6,460 — 6,460 Other 1,473 647 2,120 7,103 9,223 Corporate 10,107 953 11,060 14,515 25,575 Total fiscal year 2018 $ 27,360 $ 3,868 $ 31,228 $ 21,618 $ 52,846 Fiscal Year 2020 For fiscal year 2020 , we recorded restructuring charges of $10.8 million , which included $5.3 million related to the termination of approximately 191 employees and $5.5 million charge related to closing certain idle facilities. These actions were part of our strategic initiatives focused on investment rationalization, process optimization and cost reduction as we continue to evaluate the footprint of our offices and facilities. We expect the remaining outstanding severance of $1.2 million to be substantially paid during fiscal year 2021, and the remaining $15.6 million lease payments to be made through fiscal year 2027, in accordance with the terms of the applicable leases. Additionally, during fiscal year 2020 , we recorded $5.1 million expenses related to the separation of our Automotive business, and a $2.0 million impairment charge related to a right-of-use asset due to the COVID-19 pandemic, offset in part by a $0.3 million insurance reimbursement related to the 2017 Malware Incident. Fiscal Year 2019 For fiscal year 2019 , we recorded restructuring charges of $16.4 million , which included $14.2 million related to the termination of approximately 305 employees and $2.2 million in charges related to the closing of certain idle facilities. These actions were part of our strategic initiatives focused on investment rationalization, process optimization and cost reduction. Additionally, during fiscal year 2019 , we recorded $9.9 million of professional services fees related to our corporate transformational efforts and $3.3 million accelerated depreciation related to our Mobile Operator Services, offset in part by a $0.5 million insurance reimbursement related to the 2017 Malware Incident. Fiscal Year 2018 For fiscal year 2018 , we recorded restructuring charges of $31.2 million , which included $27.4 million related to the termination of approximately 1,250 terminated employees and $3.9 million in charges related to the closing of certain idle facilities, including adjustment to sublease assumptions associated with these facilities. These actions were part of our strategic initiatives focused on investment rationalization, process optimization and cost reduction. Additionally, during fiscal year 2018 , we recorded $5.7 million for costs related to the transition agreement of our former CEO, $4.8 million of professional services fees related to assessment and establishment of our corporate transformational efforts, $4.0 million related to our remediation and restoration effort after the 2017 Malware Incident, and fixed asset impairment charges of $7.1 million for SRS and Devices, as more fully described in Note 6 .

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Sep. 30, 2020
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Cash paid for Interest and Income Taxes Year Ended September 30, 2020 2019 2018 (Dollars in thousands) Interest paid $ 50,346 $ 72,630 $ 93,121 Income taxes paid $ 30,918 $ 19,439 $ 13,758

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Sep. 30, 2020
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders' Equity Share Repurchases On April 29, 2013 , our Board of Directors approved a share repurchase program for up to $500.0 million , which was increased by $500.0 million on April 29, 2015. On August 1, 2018 , our Board of Directors approved an additional $500.0 million under our share repurchase program. Under the terms of the share repurchase program, we have the ability to repurchase shares from time to time through a variety of methods, which may include open market purchases, privately negotiated transactions, block trades, accelerated share repurchase transactions, or any combination of such methods. The share repurchase program does not require us to acquire any specific number of shares and may be modified, suspended, extended or terminated by us at any time without prior notice. The timing and the amount of any purchases are subject to our assessment of the prevailing market conditions, general economic conditions, capital allocation alternatives, and other factors. We repurchased 9.5 million shares, 8.2 million shares and 9.7 million shares for $169.2 million , $126.9 million and $136.1 million during the fiscal years ended September 30, 2020 , 2019 and 2018 , respectively, under the program. The amount paid in excess of par value is recognized in additional paid in capital and these shares were retired upon repurchase. Since the commencement of the program, we have repurchased 73.8 million shares for $1,238.8 million . The amount paid in excess of par value is recognized in additional paid in capital. Shares were retired upon repurchase. As of September 30, 2020 , approximately $261.2 million remained available for future repurchases under the program. Preferred Stock We are authorized to issue up to 40,000,000 shares of preferred stock, par value $0.001 per share. The undesignated shares of preferred stock will have rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, as shall be determined by the Board of Directors upon issuance of the preferred stock. There were no outstanding shares of preferred stock as of September 30, 2020 or September 30, 2019 . Series A Preferred Stock We have designated 1,000,000 shares as Series A Preferred Stock, par value $0.001 per share. The Series A Preferred Stock is entitled to receive dividends equal to the greater of $1.00 and 1,000 times the aggregate per share amount of all dividends declared on our Common Stock. Holders of each share of the Series A Preferred Stock are entitled to 1,000 votes on all matters submitted to a vote of the stockholders of the Company and shall vote as one class. The Series A Preferred Stock is not redeemable and has the right to certain liquidation preferences over our Common Stock. The Series A Preferred Stock ranks junior to all other series of the Preferred Stock as to the payment of dividends and the distribution of assets. There were no outstanding shares of preferred stock as of September 30, 2020 or September 30, 2019 . Series B Preferred Stock We have designated 15,000,000 shares as Series B Preferred Stock, par value $0.001 per share. The Series B Preferred Stock is convertible into shares of common stock on a one-for-one basis and has a liquidation preference of $1.30 per share plus all declared but unpaid dividends. The holders of Series B Preferred Stock are entitled to non-cumulative dividends at the rate of $0.05 per annum per share, payable when, and if, declared by the Board of Directors. To date, no dividends have been declared by the Board of Directors. Holders of Series B Preferred Stock have no voting rights, except those rights provided under Delaware law. There were no outstanding shares of preferred stock as of September 30, 2020 or September 30, 2019 .

earnings per share (Notes)

earnings per share (Notes)	12 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Net Income (Loss) Per Share The following table sets forth the computation for basic and diluted net income (loss) per share (in thousands, except per share amounts): Year Ended September 30, 2020 2019 2018 (ASC 606) (ASC 606) (ASC 605) Numerator: Net income (loss) from continuing operations $ 28,782 $ (12,198 ) $ (236,837 ) Net (loss) income from discontinued operations (7,386 ) 226,008 76,909 Net income (loss) $ 21,396 $ 213,810 $ (159,928 ) Denominator: Weighted average common shares outstanding — Basic 282,644 286,347 291,318 Dilutive effect of convertible instruments 3,286 — — Dilutive effect of employee stock compensation plans (a) 6,064 — — Weighted average common shares outstanding — Diluted 291,994 286,347 291,318 Net income (loss) per common share - basic: Continuing operations $ 0.10 $ (0.04 ) $ (0.81 ) Discontinued operations (0.02 ) 0.79 0.26 Total net income (loss) per basic common share $ 0.08 $ 0.75 $ (0.55 ) Net income (loss) per common share - diluted: Continuing operations $ 0.10 $ (0.04 ) $ (0.81 ) Discontinued operations (0.03 ) 0.79 0.26 Total net income (loss) per diluted common share $ 0.07 $ 0.75 $ (0.55 ) Anti-dilutive equity instruments excluded from the calculation 453 1,047 528 Contingently issuable awards excluded from the calculation (a) 9 1,786 4,434 (a) Certain performance-based awards were excluded from the determination of dilutive net income (loss) per share as the conditions were not met at the end of the reporting period.
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Year Ended September 30, 2020 2019 2018 (ASC 606) (ASC 606) (ASC 605) Numerator: Net income (loss) from continuing operations $ 28,782 $ (12,198 ) $ (236,837 ) Net (loss) income from discontinued operations (7,386 ) 226,008 76,909 Net income (loss) $ 21,396 $ 213,810 $ (159,928 ) Denominator: Weighted average common shares outstanding — Basic 282,644 286,347 291,318 Dilutive effect of convertible instruments 3,286 — — Dilutive effect of employee stock compensation plans (a) 6,064 — — Weighted average common shares outstanding — Diluted 291,994 286,347 291,318 Net income (loss) per common share - basic: Continuing operations $ 0.10 $ (0.04 ) $ (0.81 ) Discontinued operations (0.02 ) 0.79 0.26 Total net income (loss) per basic common share $ 0.08 $ 0.75 $ (0.55 ) Net income (loss) per common share - diluted: Continuing operations $ 0.10 $ (0.04 ) $ (0.81 ) Discontinued operations (0.03 ) 0.79 0.26 Total net income (loss) per diluted common share $ 0.07 $ 0.75 $ (0.55 ) Anti-dilutive equity instruments excluded from the calculation 453 1,047 528 Contingently issuable awards excluded from the calculation (a) 9 1,786 4,434

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement, Noncash Expense [Abstract]
Stock-Based Compensation	17 . Stock-Based Compensation On January 22, 2020, our stockholders adopted our 2020 Stock Plan (the "2020 Stock Plan"). The 2020 Stock Plan (i) grants the Company's compensation committee the discretionary authority over the plan; (ii) makes employees, directors, consultants, and advisors of the Company and its subsidiaries eligible to receive awards; (iii) sets the number of shares of common stock that may be issued in satisfaction of awards to be 9,000,000 shares, plus the number of shares available for issuance under the amended and restated 2000 Stock Plan (the "Amended and Restated 2000 Stock Plan"); and (iv) identifies the annual limits on shares granted to each individual and the types of awards permissible. As of September 30, 2020 , we had 12.8 million shares available for future grants under the 2020 Stock Plan. We recognize stock-based compensation expenses over the requisite service periods. Our share-based awards are classified within equity upon issuance. The amounts included in the consolidated statements of operations related to stock-based compensation are as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Cost of professional services and hosting $ 24,887 $ 26,647 $ 29,053 Cost of product and licensing 510 855 814 Cost of maintenance and support 1,663 1,314 3,322 Research and development 34,902 22,508 26,968 Sales and marketing 32,040 30,394 33,150 General and administrative 39,292 37,537 33,736 Total $ 133,294 $ 119,255 $ 127,043 Modifications of Equity Awards In connection with the spin-off of our Automotive business (the "Distribution") on October 1, 2019, under the provisions of our Amended and Restated 2000 Stock Plan and our Amended and Restated Directors Stock Plan, we adjusted our then outstanding equity awards in accordance with the terms of the Employee Matters Agreement that Nuance entered into in connection with the Distribution. Effective upon the Distribution, Nuance stock options, Nuance restricted stock units ("RSUs"), and Nuance performance-based restricted stock units ("PSUs") held by employees and other service providers continuing with Nuance following the Distribution, were adjusted based on a conversion ratio of 1.16667 to 1, as outlined in the Employee Matters Agreement. Effective upon the Distribution, RSUs held by employees continuing with Cerence following the Distribution that were scheduled to vest on or before November 30, 2019 vested in full as of immediately prior to the Distribution, PSUs held by such employees that were eligible to vest based on Nuance's relative total shareholder return ("TSR") as of November 6, 2019 were cancelled in exchange for a cash payment based on the portion of the PSUs that were then earned, and all other RSUs and PSUs held by such employees were forfeited for no consideration upon their termination of employment with Nuance. As of the Distribution (or an applicable employee's later transfer date), all employees continuing with Cerence following the Distribution ceased to be eligible to participate in Nuance's Employee Stock Purchase Plan ("ESPP"). As of September 30, 2020 , the employees participating in our ESPP were all Nuance employees. There were no changes to the plan terms of any of the foregoing plans except as described above. The incremental expense as a result of these modification was immaterial to the condensed consolidated financial statements. Stock Options We have share-based award plans under which employees, officers and directors may be granted stock options to purchase our common stock, generally at the fair market value of the grant date. Our plans do not allow for options to be granted at below fair market value, nor can they be re-priced at any time. Options granted under our plans generally become exercisable over a period of two to four years and have a maximum term of ten years. We have also assumed options and option plans in connection with certain of our acquisitions. These stock options are governed by the plans and agreements that they were originally issued under but are now exercisable for shares of our common stock. The table below summarizes activities related to stock options for the years ended September 30, 2020 , 2019 and 2018 : Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (a) Outstanding at September 30, 2017 23,807 $ 15.39 Exercised (2,963 ) $ 2.61 Expired (1,700 ) $ 15.99 Outstanding at September 30, 2018 19,144 $ 17.31 Exercised (3,314 ) $ 7.22 Expired (4,528 ) $ 17.89 Outstanding at September 30, 2019 11,302 $ 20.04 Exercised (3,830 ) $ 17.18 Equitable Adjustment - Cerence Spin-off (b) 1,883 Outstanding at September 30, 2020 9,355 $ 17.18 1.6 years $ 0.1 million Exercisable at September 30, 2020 9,355 $ 17.18 1.6 years $ 0.1 million Exercisable at September 30, 2019 11,302 Exercisable at September 30, 2018 19,144 (a) The aggregate intrinsic value represents any excess of the closing price of our common stock as of September 30, 2020 ( $33.19 ) over the exercise price of the underlying options. (b) Effective with the Distribution on October 1, 2019, outstanding equity awards were equitably adjusted by a conversion ratio of 1.16667 per one Nuance share then held. The aggregate intrinsic values of stock options exercised during the fiscal year ended September 30, 2020 , 2019 , and 2018 were de minimis. Restricted Stock Units and Performance Stock Units We are authorized to issue equity incentive awards in the form of RSUs and PSUs. Unvested awards may not be sold, transferred or assigned. Both RSUs and PSUs are service-based awards and generally vested over a three-year period. The fair value of the RSUs is measured based upon the market price of the underlying common stock as of the grant date. PSUs are aligned to specified performance targets, such as total shareholder return relative to our peers, or specified performance metrics. PSUs generally cliff vest at the end of a three-year period, which is contingent upon the achievement of such performance targets as well as the employee's continued employment. The fair value of PSUs aligned to the returns of our common stock, or TSRs, is determined using a Monte Carlo simulation model. The fair value of PSUs aligned to specified performance metrics is determined based upon our best estimate of the probability of achieving these goals. The fair value of an award at the grant date is amortized to expense over the requisite service period using the straight-line method, net of an assumed forfeiture rate assumption. In the event that the employees’ employment with us terminates, or in the case of awards with only performance goals, if those goals are not met, any unvested shares are forfeited and reverted to us. In order to satisfy our employees’ withholding tax liability as a result of the vesting of RSU and PSUs, we have historically repurchased shares upon the employees’ vesting. We repurchased 2.9 million shares for $56.5 million in fiscal year 2020, 2.6 million shares for $42.6 million in fiscal year 2019, and 3.3 million shares for $52.3 million in fiscal year 2018. RSUs and PSUs are not included in issued and outstanding common stock until the shares are vested and released. The table below summarizes activity relating to Restricted Units: Number of Shares Number of Shares Outstanding at September 30, 2017 5,043,931 6,477,164 Granted 2,175,537 8,876,712 Earned/released (2,092,862 ) (7,156,468 ) Forfeited (2,087,038 ) (1,325,321 ) Outstanding at September 30, 2018 3,039,568 6,872,087 Granted 1,342,836 9,500,077 Earned/released (1,405,485 ) (6,383,908 ) Modification (a) (296,759 ) 296,759 Forfeited (688,835 ) (1,286,071 ) Outstanding at September 30, 2019 1,991,325 8,998,944 Granted 1,067,900 6,401,949 Earned/released (303,198 ) (8,106,783 ) Forfeited (438,981 ) (1,452,467 ) Equitable Adjustment - Cerence Spin-off (b) 303,074 1,316,006 Outstanding at September 30, 2020 2,620,120 7,157,649 Weighted average remaining recognition period of outstanding Restricted Units 1.4 years 1.7 years Unrecognized stock-based compensation expense of outstanding Restricted Units $19.1 million $79.7 million Aggregate intrinsic value of outstanding Restricted Units (C) $87.0 million $237.6 million (a) 296,759 shares of performance-based awards were modified to time-based awards with only service conditions in December 2018. (b) Effective with the Distribution on October 1, 2019, outstanding equity awards were equitably adjusted by a conversion ratio of 1.16667 per one Nuance share then held. (c) The aggregate intrinsic value represents any excess of the closing price of our common stock as of September 30, 2020 ( $33.19 ) over the exercise price of the underlying restricted units. A summary of the weighted-average grant-date fair value of RSUs and PSUs granted, and the aggregate intrinsic value of Restricted Units vested for each fiscal year is as follows: Year ended September 30, 2020 2019 2018 Weighted-average grant-date fair value per share $ 19.51 $ 16.52 $ 15.47 Total intrinsic value of shares vested (in millions) $ 164.1 $ 125.2 $ 146.5 PSUs outstanding as of September 30, 2020 and issued in fiscal year 2019 include performance goals based on total shareholder return relative to our peers during the performance period. The awards actually earned will be up to two hundred percent of the targeted number of the PSUs. Compensation expense is recorded ratably over the performance period of the award based on the estimated grant date fair value estimated at the grant date using a Monte Carlo simulation model, which included the following assumptions: Year ended September 30, 2020 2019 Dividend yield 0.0 % 0.0 % Expected volatility 27.73% - 28.24% 27.32% - 30.85% Risk-free interest rate 1.40% - 1.62% 2.23% - 3.02% Expected term (in years) 2.72 - 3 1 - 3 1995 Employee Stock Purchase Plan The ESPP, as amended and restated on January 27, 2015 , authorizes the issuance of a maximum of 20,000,000 shares of common stock in semi-annual offerings to employees at a price equal to the lower of 85% of the closing price on the applicable offering commencement date or 85% of the closing price on the applicable offering termination date. Stock-based compensation expense for the employee stock purchase plan is recognized for the fair value benefit accorded to participating employees. At September 30, 2020 , we have reserved 3.6 million shares for future issuance. A summary of the weighted-average grant-date fair value, shares issued, and total stock-based compensation expense recognized related to the ESPP are as follows: Year ended September 30, 2020 2019 2018 Weighted-average grant-date fair value per share $ 6.90 $ 3.76 $ 4.00 Total shares issued (in millions) 1.0 1.2 1.3 Total stock-based compensation expense (in millions) $ 4.2 $ 4.5 $ 5.2 The fair value of the purchase rights granted under the ESPP was estimated on the date of grant using the Black-Scholes option-pricing model that uses the following weighted-average assumptions, which were derived in a manner similar to those discussed above relative to stock options: Year ended September 30, 2020 2019 2018 Dividend yield 0.0 % 0.0 % 0.0 % Expected volatility 39.8 % 27.8 % 32.1 % Risk-free interest rate 0.9 % 2.2 % 2.0 % Expected term (in years) 0.5 0.5 0.5

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation and Other Claims Similar to many companies in the software industry, we are involved in a variety of claims, demands, suits, investigations and proceedings that arise from time to time relating to matters incidental to the ordinary course of our business, including actions with respect to contracts, intellectual property, employment, benefits and securities matters. At each balance sheet date, we evaluate contingent liabilities associated with these matters in accordance with ASC 450 "Contingencies". If the potential loss from any claim or legal proceeding is considered probable and the amount can be reasonably estimated, we accrue a liability for the estimated loss. Significant judgments are required for the determination of probability and the range of the outcomes, and the estimates are based only on the information available at the time. Due to the inherent uncertainties involved in claims, legal proceedings, and in estimating the losses that may arise, actual outcomes may differ from our estimates. Contingencies deemed not probable or for which losses were not estimable in one period may become probable, or losses may become estimable in later periods which may have a material impact on our results of operations and financial position. As additional information becomes available, we reassess the potential liability related to our pending claims and litigation and may revise our estimates. As of September 30, 2020 and 2019 , accrued losses were not material to our consolidated financial statements, and we do not expect any pending matter to have a material impact on our consolidated financial statements. Guarantees and Other We include indemnification provisions in the contracts we enter into with customers and business partners. Generally, these provisions require us to defend claims arising out of our products’ infringement of third-party intellectual property rights, breach of contractual obligations and/or unlawful or otherwise culpable conduct. The indemnity obligations generally cover damages, costs and attorneys’ fees arising out of such claims. In most, but not all cases, our total liability under such provisions is limited to either the value of the contract or a specified, agreed upon amount. In some cases, our total liability under such provisions is unlimited. In many, but not all cases, the term of the indemnity provision is perpetual. While the maximum potential amount of future payments we could be required to make under all the indemnification provisions is unlimited, we believe the estimated fair value of these provisions is minimal due to the low frequency with which these provisions have been triggered. We indemnify our directors and officers to the fullest extent permitted by Delaware law, which provides among other things, indemnification to directors and officers for expenses, judgments, fines, penalties and settlement amounts incurred by such persons in their capacity as a director or officer of the company, regardless of whether the individual is serving in any such capacity at the time the liability or expense is incurred. Additionally, in connection with certain acquisitions, we agreed to indemnify the former officers and members of the boards of directors of those companies, on similar terms as described above, for a period of six years from the acquisition date. In certain cases, we purchase director and officer insurance policies related to these obligations, which fully cover the six-year period. To the extent that we do not purchase a director and officer insurance policy for the full period of any contractual indemnification, and such directors and officers do not have coverage under separate insurance policies, we would be required to pay for costs incurred, if any, as described above.

Pension and Other Post-Retireme

Pension and Other Post-Retirement Benefits	12 Months Ended
	Sep. 30, 2020
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefits	Pension and Other Post-Retirement Benefits Defined Contribution Plans We have established a retirement savings plan under Section 401(k) of the Internal Revenue Code (the “401(k) Plan”). The 401(k) Plan covers substantially all of our U.S. employees who meet minimum age and service requirements, and allows participants to defer a portion of their annual compensation on a pre-tax basis. Effective on January 1, 2020, we now match 100% of the first 3% of employee contributions of eligible salaries, and 50% of the next 2% of employee contributions of eligible salaries for a total maximum match of 4% . Additionally, any employer's contributions made after January 1, 2020 will now be vested immediately, and employer contributions made before this date will continue to be vested on the prior schedule. Our contributions to the 401(k) Plan that covers substantially all of our U.S. employees who meet the minimum requirements totaled $12.0 million , $7.3 million and $6.1 million for fiscal years 2020 , 2019 and 2018 , respectively. We make contributions to various other plans in certain of our foreign operations; total contributions to these plans are not material. Defined Benefit Plans We sponsor certain defined benefit plans that are offered primarily by our foreign subsidiaries. Many of these plans were assumed through our acquisitions or are required by local regulatory requirements. We may deposit funds for these plans with insurance companies, third party trustees, or into government-managed accounts consistent with local regulatory requirements, as applicable. Our defined benefit pension income was $0.4 million , $0.5 million , and $0.1 million for fiscal years 2020 , 2019 , and 2018 , respectively. The aggregate projected benefit obligation as of September 30, 2020 and September 30, 2019 was $35.4 million and $35.2 million , respectively. The aggregate net liability of our defined benefit plans as of September 30, 2020 and September 30, 2019 was $13.2 million and $12.6 million , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Recent Tax Legislation On December 22, 2017, the TCJA was signed into law. The TCJA significantly revises the U.S. corporate income tax by, among other things, lowering corporate income tax rates, implementing a hybrid territorial tax system, and imposing a mandatory one-time repatriation tax on foreign cash and earnings. We are subject to additional requirements of the TCJA during the year ended September 30, 2020 and 2019 . The material provisions affecting the Company include a tax on global intangible low-taxed income (“GILTI”), a limitation of certain executive compensation, a base erosion and anti-abuse tax ("BEAT"). Our fiscal year 2019 and 2020 effective tax rate includes our estimates of these new provisions. Our estimates of the impact of these provisions may change in future periods as we obtain additional data and as the IRS issues new guidance implementing the law changes. As a result of the TCJA, in fiscal year 2018 we remeasured certain deferred tax assets and liabilities at the lower rates and recorded approximately $92.9 million of tax benefits. Additionally, as of September 30, 2018 , we recorded a $5.8 million provision for the deemed repatriation of foreign cash and earnings, which is estimated based upon estimated foreign earnings and foreign income taxes. On March 27, 2020, the CARES Act was enacted, which provided a technical correction to a provision in the TCJA related to the characterization of federal net operating losses ("NOLs") generated during fiscal year 2018. Under the TCJA, NOLs generated in fiscal years that straddled December 31, 2017 were designated as indefinite-lived NOLs. The CARES Act amended this legislation to designate these NOLs as definite-lived NOLs. This recharacterization resulted in an increase of $6.5 million in deferred tax assets related to our definite lived NOLs, thus requiring additional valuation allowance of the same amount. (Benefit) Provision for Income Taxes The components of income (loss) before income taxes are as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Domestic $ (21,170 ) $ (3,325 ) $ (230,955 ) Foreign 31,200 3,232 (83,042 ) Income (loss) before income taxes $ 10,030 $ (93 ) $ (313,997 ) The components of the (benefit) provision for income taxes are as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Current: Federal $ 6,654 $ 5,023 $ (5,084 ) State 740 1,214 (2,007 ) Foreign 13,791 18,305 18,338 Total current 21,185 24,542 11,247 Deferred: Federal (17,969 ) 7,727 (84,569 ) State (13,216 ) 1,477 1,986 Foreign (8,752 ) (21,641 ) (5,824 ) Total deferred (39,937 ) (12,437 ) (88,407 ) (Benefit) provision for income taxes $ (18,752 ) $ 12,105 $ (77,160 ) Effective income tax rate (187.0 )% (13,016.1 )% 24.6 % The (benefit) provision for income taxes differed from the amount computed by applying the federal statutory rate to our income tax before income taxes as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Federal tax benefit at statutory rate $ 2,106 $ (20 ) $ (77,029 ) State tax (benefit) provision, net of federal benefit (9,740 ) 2,328 (508 ) Foreign tax rate and other foreign related tax items (4,047 ) 7,708 (4,275 ) Stock-based compensation (3,830 ) 3,368 3,290 Non-deductible expenditures 481 2,696 1,927 Executive compensation 6,445 1,662 503 Change in U.S. and foreign valuation allowance (28,709 ) 188,510 57,281 Capital losses 10,443 (179,635 ) — Intangible property transfers (14,800 ) (23,428 ) — Uncertain tax positions 18,020 4,428 4,415 Base erosion and anti-abuse tax 6,619 5,023 — TCJA impact — — (87,058 ) Goodwill impairment — — 28,640 Tax credits (11,206 ) (561 ) (4,499 ) Foreign dividend 12,806 1,026 736 Debt repurchases (3,442 ) — — Other 102 (1,000 ) (583 ) (Benefit) provision for income taxes $ (18,752 ) $ 12,105 $ (77,160 ) The effective income tax rate is based upon the income for the year, the composition of the income in different countries, changes relating to valuation allowances and as necessary, and adjustments, if any, for the potential tax consequences of resolving audits or other tax contingencies. Our effective income tax rate may vary based on the geographic mix of our income. The effective income tax rate in fiscal year 2020 differs from the U.S. federal statutory rate of 21.0% primarily due to a net $29.9 million deferred tax benefit from adjustments to domestic valuation allowance primarily related to the Cerence spin-off, a foreign tax benefit of $14.8 million related to prior year intangible property transfers, partially offset by uncertain tax positions and the base erosion and anti-abuse tax. The effective income tax rate in fiscal year 2019 differs from the U.S. federal statutory rate of 21.0% primarily due to a net tax benefit related to intangible property transfers, partially offset by the base erosion and anti-abuse tax and uncertain tax positions. As part of the restructuring for the spin-off of our Automotive business, we recognized an $857.8 million gross U.S. capital loss with a potential tax benefit of $180.1 million . We believe that it is not more likely than not that the tax benefit from the U.S. capital loss will be realized. As a result, we recorded a full valuation allowance against the capital loss. The effective income tax rate in fiscal year 2018 differs from the U.S. federal statutory rate of 24.5% primarily due to the net tax benefits resulting from the TCJA remeasurement of deferred tax assets and liabilities at the lower enacted rate, and our foreign earnings subject to lower tax rates, offset in part by additional valuation allowance related to current period losses, and the tax effect of goodwill impairment charges that are not deductible. As of September 30, 2020 , foreign earnings of approximately $294.0 million have been retained by foreign subsidiaries for reinvestment. No provision has been made for deferred taxes on undistributed earnings of non-U.S. subsidiaries as these earnings have been indefinitely invested or expected to be remitted substantially free of additional tax. Determination of the amount of unrecognized deferred tax liability on these undistributed earnings is not practicable because of the complexity of laws and regulations, varying tax treatment of alternative repatriation scenarios, and the variation due to multiple potential assumptions relating to the timing of any future repatriations. Deferred tax assets (liabilities) consist of the following as of September 30, 2020 and 2019 (dollars in thousands): September 30, 2020 September 30, 2019 Deferred tax assets: Net operating loss carryforwards $ 121,375 $ 166,224 Capital loss carryforwards 169,480 188,320 Federal and state credit carryforwards 44,181 43,897 Accrued expenses and other reserves 19,703 33,150 Difference in timing of revenue related items — 24,832 Deferred compensation 20,088 22,917 Lease liabilities 23,874 — Other 18,697 11,579 Total deferred tax assets 417,398 490,919 Valuation allowance for deferred tax assets (230,322 ) (303,378 ) Net deferred tax assets 187,076 187,541 Deferred tax liabilities: Depreciation (20,781 ) (16,833 ) Convertible debt (86,667 ) (87,046 ) Acquired intangibles (56,794 ) (7,517 ) Difference in timing of revenue related items (26,787 ) — Right-of-Use assets (18,345 ) — Net deferred tax (liabilities) assets $ (22,298 ) $ 76,145 Reported as: Other assets $ 47,818 $ 130,361 Long-term deferred tax liabilities (70,116 ) (54,216 ) Net deferred tax (liabilities) assets $ (22,298 ) $ 76,145 Deferred tax assets are reduced by a valuation allowance if, based on the weight of available positive and negative evidence, it is more likely than not that some portion or all the deferred tax assets will not be realized. During fiscal year 2020 , the valuation allowance for deferred tax assets decreased by $73.1 million . This decrease relates to the valuation allowance for deferred taxes related to Cerence which was spun off in fiscal year 2020, partially offset by additional valuation allowance for federal and state credit carryforwards. As of September 30, 2020 , we have $198.9 million and $31.4 million in valuation allowance against our net domestic and foreign deferred tax assets, respectively. As of September 30, 2019 , we had $269.6 million and $33.8 million in valuation allowance against our net domestic and foreign deferred tax assets, respectively. Valuation Allowances As of September 30, 2020 , and September 30, 2019 , we had a full valuation allowance against net domestic deferred tax assets and certain foreign deferred tax assets. We intend to maintain valuation allowances on these deferred tax assets until there is sufficient evidence to support the release of all or some portion of these allowances. A significant portion of our domestic deferred tax assets relate to U.S. net operating losses. Cumulative pretax losses have historically represented significant negative evidence of our ability to realize our domestic deferred tax assets. We continue to evaluate all sources of domestic taxable income including both the reversal of existing deferred tax liabilities and the likelihood that we could sustain pretax profitability in the future. As of September 30, 2020 , we believe that there is a reasonable possibility that within the next twelve months these sources of taxable income may become sufficient positive evidence to support a conclusion that a substantial portion of the domestic valuation allowance, excluding capital losses, could be released. Automotive Deferred Taxes As discussed within Note 4 , the Company has elected to classify the deferred tax assets and liabilities associated with assets and liabilities held for sale (including those spun-off) with the Company's other deferred tax assets and liabilities. As such, the deferred tax assets and liabilities reflected above include those associated with the business reported within the balance sheet item Assets Held for Sale. The net amount of estimated deferred tax assets associated with the Automotive segment as of September 30, 2019 is $73.8 million . At September 30, 2020 and 2019 , we had U.S. federal net operating loss carryforwards of $370.5 million and $551.1 million , respectively. At September 30, 2020 and 2019 , we had state net operating loss carryforwards of $196.0 million and $194.6 million , respectively. Certain net operating loss and credit carryforwards are subject to an annual limitation due to the ownership change limitations provided by the Internal Revenue Code of 1986 and similar state tax provisions. As of September 30, 2020 and 2019 , we had foreign net operating loss carryforwards of $154.8 million and $191.7 million , respectively. These carryforwards will expire at various dates beginning in 2020 and extending up to an unlimited period. As of September 30, 2020 and 2019 , we had federal research and development carryforwards and foreign tax credit carryforwards of $56.6 million and $27.7 million , respectively. As of September 30, 2020 and 2019 , we had state research and development credit and investment tax credit carryforwards of $13.1 million and $3.9 million , respectively. As of September 30, 2020 and 2019 , we had foreign investment tax credit carryforwards of $8.4 million and $14.3 million , respectively. Uncertain Tax Positions We believe that our income tax reserves are adequate; however, amounts asserted by taxing authorities could be greater or less than amounts accrued and reflected in our consolidated balance sheets. Accordingly, we could record adjustments to the amounts for federal, foreign, and state tax-related liabilities in the future as we revise estimates or as we settle or otherwise resolve the underlying matters. In the ordinary course of business, we may take new positions that could increase or decrease our unrecognized tax benefits in future periods. The aggregate changes in the balance of our gross unrecognized tax (benefits) provisions were as follows (dollars in thousands): Year Ended September 30, 2020 2019 Balance at the beginning of the year $ 24,111 $ 19,491 Increases related to tax positions from prior fiscal years 38,006 — Increases for tax positions taken during current period 6,866 5,517 Decreases for tax settlements and lapse in statutes (8,915 ) (860 ) Cumulative translation adjustments 413 (37 ) Balance at the end of the year $ 60,481 $ 24,111 As of September 30, 2020 , $60.5 million of the unrecognized tax benefits, if recognized, would impact our effective income tax rate. We recognized interest and penalties related to uncertain tax positions in our provision for income taxes of $2.1 million , $1.4 million , and $0.8 million during fiscal years 2020 , 2019 , and 2018 , respectively. We recorded interest and penalties of $8.1 million and $8.9 million as of September 30, 2020 and 2019 , respectively. We are subject to U.S. federal income tax, various state and local taxes, and international income taxes in numerous jurisdictions. The federal tax returns for 2001 through 2016 remain subject to examination for the purpose of determining the amount of remaining tax NOL and other carryforwards. Additionally, the federal tax returns for 2017 through 2019 years remain open for all purposes of examination by the IRS and other taxing authorities in material jurisdictions.

Related Party Transaction (Note

Related Party Transaction (Notes)	12 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	Related Party Transaction In January 2018, we entered into a software and license agreement (the "License Agreement") with Magnet Systems, Inc. ("Magnet") which was pre-approved by our Board of Directors. A member of the Magnet board of directors also served on our board of directors at the time of the transaction. Pursuant to the License Agreement, Magnet granted us a perpetual software license to certain technology for a one-time payment of $5.0 million in cash, with $3.5 million paid immediately upon the effective date of the License Agreement and $1.5 million payable upon the earlier of (i) the 120-day period following the effective date of the License Agreement or (ii) signature of a statement of work for the engineering services described below. Additionally, we entered into a service agreement (the "Service Agreement") with Magnet, pursuant to which Magnet will provide engineering services to assist in integrating the licensed technology into certain of our Enterprise solutions. Based upon the statement of work signed on April 19, 2018, total fees under the Service Agreement should not exceed $2.0 million and are payable in six equal monthly installments upon the signature of the statement of work, which was finalized within 90 days following the effective date of the License Agreement. We incurred $2.0 million service costs by the time the integration service was completed on March 31, 2019.

Segment and Geographic Informat

Segment and Geographic Information and Significant Customers	12 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment and Geographic Information and Significant Customers	Segment and Geographic Information Our Chief Operating Decision Maker ("CODM") regularly reviews segment revenues and segment profits for performance evaluation and resources allocation. Segment revenues include certain acquisition-related adjustments for revenues that would otherwise have been recognized without the acquisition. Segment profits reflect controllable costs directly related to each segment and the allocation of certain corporate expenses such as, corporate sales and marketing expenses and research and development project costs that benefit multiple segments. Certain items such as stock-based compensation, amortization of intangible assets, acquisition-related costs, net, restructuring and other charges, net, other expenses, net and certain unallocated corporate expenses are excluded from segment profits, which allow for more meaningful comparisons to the financial results of the historical operations for performance evaluation and resources allocation by our CODM. • The Healthcare segment is primarily engaged in providing clinical speech and clinical language understanding solutions that improve the clinical documentation process, from capturing the complete patient record to improving clinical documentation and quality measures for reimbursement. • The Enterprise segment is primarily engaged in using speech, natural language understanding, and artificial intelligence to provide automated customer solutions and services for voice, mobile, web and messaging channels. • The Other segment consists primarily of voicemail transcription services after the sale of our Mobile Operator Services and the wind-down of devices in 2019. We do not track our assets by segment. Consequently, it is not practical to show assets or depreciation by segment. The following table presents segment results along with a reconciliation of segment profits to income (loss) before income taxes (dollars in thousands): Year Ended September 30, 2020 2019 2018 Segment revenues: (ASC 606) (ASC 606) (ASC 605) Healthcare $ 915,332 $ 950,593 $ 984,819 Enterprise 529,978 510,753 483,194 Other 33,890 61,461 109,064 Total segment revenues 1,479,200 1,522,807 1,577,077 Acquisition related revenue adjustments (a) (301 ) (1,536 ) (9,477 ) Total consolidated revenue 1,478,899 1,521,271 1,567,600 Segment profit: Healthcare 298,751 333,526 322,715 Enterprise 146,923 131,169 130,173 Other 19,725 19,555 24,157 Total segment profit 465,399 484,250 477,045 Corporate expenses and other, net (119,945 ) (137,558 ) (183,657 ) Acquisition-related revenues and costs of revenues adjustment (301 ) (1,536 ) (9,477 ) Stock-based compensation (133,294 ) (119,255 ) (127,043 ) Amortization of intangible assets (78,707 ) (81,622 ) (105,375 ) Acquisition-related costs, net (2,884 ) (7,965 ) (12,010 ) Restructuring and other charges, net (17,680 ) (29,147 ) (52,846 ) Impairment of goodwill and other intangible assets — — (170,941 ) Other expenses, net (102,558 ) (107,260 ) (129,693 ) Income (loss) before income taxes $ 10,030 $ (93 ) $ (313,997 ) (a) Segment revenues differ from reported revenues due to certain revenue adjustments related to acquisitions that would otherwise have been recognized but for the purchase accounting treatment of the business combinations. These revenues are included to allow for more complete comparisons to the financial results of historical operations and in evaluating management performance. No country outside of the United States provided greater than 10% of our total revenue. Revenue, classified by the major geographic areas in which our customers are located, was as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 (ASC 606) (ASC 606) (ASC 605) United States $ 1,185,760 $ 1,237,406 $ 1,255,203 International 293,139 283,865 312,397 Total $ 1,478,899 $ 1,521,271 $ 1,567,600 No country outside of the United States held greater than 10% of our long-lived or total assets. Our long-lived assets from continuing operations, including intangible assets and goodwill, were located as follows (dollars in thousands): September 30, September 30, United States $ 2,254,424 $ 2,086,932 International 602,923 787,040 Total $ 2,857,347 $ 2,873,972

Subsequent events

Subsequent events	12 Months Ended
	Sep. 30, 2020
Subsequent Event [Line Items]
Subsequent Events [Text Block]	25 . Subsequent Event In connection with our ongoing comprehensive portfolio and business review, during the first quarter of 2021, we announced our strategic plan to sell our medical transcription and EHR go-live businesses to Assured Healthcare Partners and Aeries Technology Group. These businesses provide critical support to healthcare organizations, and upon the closing of the sale, Nuance will be both a minority stakeholder and business partner committed to the success of the new business, named DeliverHealth Solutions. As a result, we expect the results of medical transcription and EHR go-live businesses to be included within discontinued operations on the consolidated statements of operations, and the related assets and liabilities to be classified as assets and liabilities held for sale on the consolidated balance sheets effective the first quarter of fiscal year 2021. The change in financial statement presentation may trigger changes in reporting units, which may result in a goodwill impairment charge of $10 million to $20 million during the first quarter of fiscal year 2021.

Quarterly Data (Unaudited)

Quarterly Data (Unaudited)	12 Months Ended
	Sep. 30, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Data (Unaudited)	Quarterly Data (Unaudited) The following information has been derived from unaudited consolidated financial statements that, in the opinion of management, include all recurring adjustments necessary for a fair statement of such information (dollars in thousands, except per share amounts): First Quarter Second Quarter (a) Third Quarter Fourth Quarter Fiscal Year 2020 Total revenue $ 418,233 $ 369,337 $ 338,398 $ 352,931 $ 1,478,899 Gross profit $ 233,844 $ 212,244 $ 194,216 $ 199,656 $ 839,960 Net income (loss) from continuing operations $ 54,877 $ (20,006 ) $ 16,662 $ (22,751 ) $ 28,782 Net income (loss) per share - continuing operations: Basic $ 0.19 $ (0.07 ) $ 0.06 $ (0.08 ) $ 0.10 Diluted $ 0.19 $ (0.07 ) $ 0.06 $ (0.08 ) $ 0.10 Weighted average common shares outstanding: Basic 284,130 282,576 281,281 282,556 282,644 Diluted 289,453 282,576 287,852 282,556 291,994 First Quarter Second Quarter Third Quarter Fourth Quarter Fiscal Year 2019 Total revenue $ 419,675 $ 336,584 $ 377,437 $ 387,575 $ 1,521,271 Gross profit $ 235,555 $ 177,325 $ 205,667 $ 219,240 $ 837,787 Net income (loss) from continuing operations $ 13,881 $ (28,397 ) $ (687 ) $ 3,005 $ (12,198 ) Net income (loss) per share - continuing operations: Basic $ 0.05 $ (0.10 ) $ — $ 0.01 $ (0.04 ) Diluted $ 0.05 $ (0.10 ) $ — $ 0.01 $ (0.04 ) Weighted average common shares outstanding: Basic 287,796 285,866 285,942 285,754 286,347 Diluted 292,359 285,866 285,942 291,598 286,347 (a) On March 27, 2020, the CARES Act was enacted, which provided a technical correction to a provision in the TCJA related to the characterization of federal net operating losses ("NOLs") generated during fiscal year 2018. Under the TCJA, NOLs generated in fiscal years that straddled December 31, 2017 were designated as indefinite-lived NOLs. The CARES Act amended this legislation to designate these NOLs as definite-lived NOLs. This recharacterization resulted in an increase of $6.5 million in deferred tax assets related to our definite lived NOLs, thus requiring additional valuation allowance of the same amount. This adjustment was identified during the fiscal third quarter ending June 30, 2020. We determined that these amounts are not material to our previously issued condensed consolidated financial statements for the three months ended March 31, 2020. The amounts for the second quarter of fiscal year 2020 above have been adjusted to reflect this adjustment.

Operating Leases (Notes)

Operating Leases (Notes)	12 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases of Lessee Disclosure [Text Block]	Operating Leases We have various operating leases for office space, data centers, office equipment and automobiles around the world with lease terms expiring between 2021 and 2030 . We determine if an arrangement is a lease at inception. The current portion of our operating lease liabilities is included in accrued expenses and other current liabilities and the long-term portion is included in operating lease liabilities. Operating lease assets and liabilities are recognized at the present value of the future lease payments at the lease commencement date. The interest rate used to determine the present value of the future lease payments is our incremental borrowing rate. Due to the interest rate implicit in most of our leases not being readily determinable, our incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in economic environments where the leased asset is located. Operating lease assets also include any prepaid lease payments and lease incentives. Our lease terms include periods under options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Operating lease expense is recognized on a straight-line basis over the lease term. Our lease agreements generally contain lease and non-lease components. Non-lease components primarily include payments for maintenance and utilities. We combine fixed payments for non-lease components with our lease payments and account for them together as a single lease component which increases the amount of our lease assets and liabilities. Payments under our lease arrangements are primarily fixed. Variable rents, if any, are expensed as incurred. As of September 30, 2020 , our operating leases had a weighted average remaining lease term of 4.7 years and a weighted average discount rate of 3.8% . Future lease payments under operating leases as of September 30, 2020 were as follows (dollars in thousands): Fiscal Year Operating Leases Operating leases under restructuring Total 2021 $ 27,944 $ 4,492 $ 32,436 2022 23,162 3,805 26,967 2023 16,766 3,440 20,206 2024 14,496 1,996 16,492 2025 12,547 1,346 13,893 Thereafter 41,046 1,843 42,889 Total $ 135,961 $ 16,922 $ 152,883 As of September 30, 2020 , we have subleased certain office space that is included in the above table to third parties. As of September 30, 2020 , the aggregate sublease income to be recognized during the remaining lease terms is $12.4 million , with approximately an average of $2.1 million annually for each of the next five fiscal years and approximately $2.0 million thereafter. Our operating lease cost was approximately $32.5 million for the year ended September 30, 2020 . Operating lease payments included within operating cash flows were $33.2 million for the year ended September 30, 2020 .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2020
Summary of Significant Accounting Policies [Abstract]
New Accounting Pronouncements, Policy [Policy Text Block]	eases In February 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-02, "Leases" ("ASC 842"), which became effective for fiscal years beginning after December 15, 2018 and interim periods therein, with early adoption permitted. ASC 842 requires lessees to recognize on the balance sheet a right-of-use asset, representing its right to use the underlying asset for the lease term, and a lease liability for all leases with terms greater than 12 months. The guidance also requires qualitative and quantitative disclosures designed to assess the amount, timing, and uncertainty of cash flows arising from leases. The standard initially required the use of a modified retrospective transition approach, which includes a number of optional practical expedients that entities may elect to apply. We adopted ASC 842 in the first quarter of fiscal year 2020. In July 2018, the FASB issued ASU 2018-10, "Codification Improvements to Topic 842, Leases" and ASU 2018-11, "Leases Topic 842 Targeted Improvements", which provide an additional (and optional) transition method whereby the new lease standard is applied at the adoption date and recognized as an adjustment to retained earnings. Additionally, in March 2019, the FASB issued ASU 2019-01, "Codification Improvements to Topic 842", which provides guidance in the following areas: (1) determining the fair value of the underlying asset by lessors that are not manufacturers or dealers and (2) clarification of interim disclosure requirements during transition. We adopted ASC 842, as amended, as of October 1, 2019 under the optional transition method and elected the package of practical expedients under the transition guidance. As a result of the adoption on October 1, 2019, we recognized $120 million of operating lease right-of-use assets, and approximately $140 million of operating lease obligations. Approximately $20 million of deferred rent balances were reclassified against the costs of the right-of-use assets. The cumulative-effect adjustment to retained earnings as of October 1, 2019 was immaterial. The adoption of the guidance did not have a material impact on our consolidated statement of operations or consolidated statement of cash flows. Income Taxes In January 2018, the FASB issued ASU 2018-02, "Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income ("AOCI"), which became effective for fiscal years beginning after December 15, 2018 and interim periods therein. The guidance gives entities the option to reclassify to retained earnings the tax effects resulting from the TCJA related to items in AOCI. The guidance may be applied retrospectively to each period in which the effect of the TCJA is recognized in the period of adoption. The adoption of the guidance did not have a material impact on our condensed consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, "Income Taxes (Topic 840): Simplifying the Accounting for Income Taxes", which will become effective for fiscal years beginning after 15 December 2020 and interim periods therein. Early adoption is permitted for entities that have not yet issued their financial statements. The guidance simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in ASC 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. We adopted the guidance prospectively for fiscal year 2020. The adoption has no impact on our consolidated financial statements for fiscal years 2020, 2019 and 2018. Issued Accounting Standards Not Yet Adopted From time to time, new accounting pronouncements are issued by the FASB and are adopted by us as of the specified effective dates. Unless otherwise discussed, such pronouncements did not have or will not have a significant impact on our consolidated financial position, results of operations or cash flows, or do not apply to our operations. Internal-Use Software In August 2018, the FASB issued ASU 2018-15, "Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract", which is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, with early adoption permitted. The guidance requires that implementation costs related to a hosting arrangement that is a service contract be capitalized and amortized over the term of the hosting arrangement, starting when the module or component of the hosting arrangement is ready for its intended use. The guidance will be applied retrospectively to each period presented. We do not expect the implementation to have a material impact on our condensed consolidated financial statements. Convertible Notes In August 2020, the FASB issued ASU 2020-06, "Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity, which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The new guidance eliminates two of the three models in Accounting Standards Codification (ASC) 470-202 that require separating embedded conversion features from convertible instruments. As a result, only conversion features accounted for under the substantial premium model in ASC 470-20 and those that require bifurcation in accordance with ASC 815-153 will be accounted for separately. For contracts in an entity’s own equity, the new guidance eliminates some of the requirements in ASC 815-404 for equity classification. The guidance also addresses how convertible instruments are accounted for in the diluted earnings per share calculation and requires enhanced disclosures about the terms of convertible instruments and contracts in an entity’s own equity. The guidance will be effective for annual periods beginning after 15 December 2021, and interim periods therein. Early adoption is permitted for all entities for fiscal periods beginning after 15 December 2020, including interim periods within the same fiscal year. Entities are allowed to adopt the guidance using either the modified or full retrospective approach. We are currently assessing the provisions of the guidance but do not expect the implementation to have a material impact on our consolidated financial statement.
Derivative Financial Instruments [Policy Text Block]	ancial Instruments and Hedging Activities We use forward currency exchange contracts to manage our exposure to fluctuations in foreign currency for certain transactions. In order for instruments to be designated as hedges, specific criteria must be met, including (i) formal documentation must exist for both the hedging relationship and our risk management objectives and strategies for undertaking the hedging activities, (ii) at the inception and on an ongoing basis, the hedging relationship is expected to be highly effective in offsetting changes in fair value attributed to the hedged risk during the period that the hedge is designated, and (iii) an assessment of effectiveness is required whenever financial statements or earnings are reported. The effective portion of changes in the fair values of contracts designated as cash flow hedges is recorded in equity as a component of accumulated other comprehensive loss until the hedged item effects earnings. Once the underlying forecasted transaction is realized, the changes of fair vales of instruments designated as hedges reclassified from accumulated other comprehensive loss to the statement of operations, in the appropriate income statement line items. Any ineffective portion of the instruments designated as cash flow hedges is recognized in current earnings. We report cash flows arising from derivative financial instruments designated as fair value or cash flow hedges consistent with the classification of the cash flows from the underlying hedged items that these derivatives are hedging. No forward exchange contracts are designated as hedges for fiscal years 2020 , 2019 , or 2018 . Changes in the fair values of the forward currency exchange contracts are recorded within other expense, net . Cash flows related to investments and settlements of forward currency exchange contracts are included within cash flows from investing activities.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	centration of Risk Financial instruments that are potentially subject to significant concentrations of credit risk principally consist of cash, cash equivalents, marketable securities and trade accounts receivable. We place our cash and cash equivalents and marketable securities with financial institutions with high credit ratings. As part of our cash and investment management processes, we perform periodic evaluations of the credit standing of the financial institutions with whom we maintain deposits, and have not recorded any credit losses to-date. For trade accounts receivable, we perform ongoing credit evaluations of our customers’ financial condition and limit the amount of credit extended when deemed appropriate. No customer accounted for more than 10% of our net accounts receivable balance at September 30, 2020 and 2019 or 10% of our revenue for fiscal years 2020 , 2019 or 2018 .
Debt, Policy [Policy Text Block]	vertible Debt We bifurcate the debt and equity (the contingently convertible feature) components of our convertible debt instruments in a manner that reflects our nonconvertible debt borrowing rate at the time of issuance. The equity components of our convertible debt instruments are recorded within stockholders’ equity with an allocated issuance premium or discount. The debt issuance premium or discount is amortized to interest expense in our consolidated statement of operations using the effective interest method over the expected term of the convertible debt. We assess the short-term and long-term classification of our convertible debt on each balance sheet date. The carrying amount of the convertible debt is reclassified to current liabilities if a contingent event has occurred that makes the debt obligation puttable. The corresponding equity component classified from additional paid-in capital to mezzanine equity when the holders have the contractual rights to redeem or convert.
Advertising Cost [Policy Text Block]	ertising Costs Advertising costs are expensed as incurred and recorded within sales and marketing expenses. The advertising costs capitalized as of September 30, 2020 and 2019 are de minimis. We incurred advertising costs of $16.1 million , $16.9 million and $16.5 million for fiscal years 2020 , 2019 and 2018 , respectively.
Revenue [Policy Text Block]	enue Recognition under ASC 605 for fiscal year 2018 We derive revenue from the following sources: (1) software license agreements, including royalty and other usage-based arrangements, (2) professional services, (3) hosting services and (4) post-contract customer support ("PCS"). Our hosting services are generally provided through on-demand, usage-based or per transaction fee arrangements. Generally, we recognize revenue when (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred, (iii) the fee is fixed or determinable and (iv) collectibility is probable. The sale and/or license of software solutions and technology is deemed to have occurred when a customer either has taken possession of or has access to take immediate possession of the software or technology. Revenue from royalties on sales of our software products by original equipment manufacturers (“OEMs”), where no services are included, is recognized in the quarter earned so long as we have been notified by the OEM that such royalties are due, and provided that all other revenue recognition criteria are met. Software arrangements generally include PCS, which includes telephone support and the right to receive unspecified upgrades/enhancements on a when-and-if-available basis, typically for one to five years. Revenue from PCS is generally recognized ratably on a straight-line basis over the term that the maintenance service is provided. When PCS renews automatically, we provide a reserve based on historical experience for contracts expected to be canceled for non-payment. All known and estimated cancellations are recorded as a reduction to revenue and accounts receivable. When we provide professional services considered essential to the functionality of the software, we recognize revenue from the professional services as well as any related software licenses on a percentage-of-completion basis whereby the arrangement consideration is recognized as the services are performed, as measured by an observable input. In these circumstances, we separate license revenue from professional service revenue for income statement presentation by allocating Vendor-Specific Objective Evidence ("VSOE") of fair value of the professional services as professional services and hosting revenue and the residual portion as product and licensing revenue . We generally determine the percentage-of-completion by comparing the labor hours incurred to-date to the estimated total labor hours required to complete the project. Adjustments to estimates to complete are made in the periods in which facts resulting in a change become known. When the estimate indicates that a loss will be incurred, such loss is recorded in the period identified. In a hosting arrangement, we recognize the up-front setup fees ratably over the longer of the contract lives or the expected lives of the customer relationships. The usage-based or individual transaction fees are due and payable as each individual transaction is processed through the hosting service and is recognized as revenue in the period the services are provided. The on-demand service fees are recognized ratably over our estimate of the useful life of the devices on which the hosting service is provided. We enter into multiple-element arrangements that may include a combination of our various software related and non-software related products and services offerings, for example, software licenses, PCS, professional services, and hosting services. In such arrangements, we allocate total arrangement consideration to software or software-related elements and any non-software element separately based on the selling price hierarchy group following our policies. Where possible, we determine the selling price for each deliverable using VSOE of selling price, if it exists, or Third-Party Evidence (“TPE”) of selling price. Typically, we are unable to determine TPE of selling price. Therefore, when neither VSOE nor TPE of selling price exist for a deliverable, we use our Estimate of Selling Price (“ESP”) for the purposes of allocating the arrangement consideration. We determine ESP for a product or service by considering multiple factors including, but not limited to, major project groupings, market conditions, competitive landscape, price list and discounting practices. We have established VSOE of fair value for the majority of our PCS, professional services, and training. Revenue allocated to each element is then recognized when the basic revenue recognition criteria are met for each element. See Note 3 for revenue recognition under ASC 606 for fiscal years 2020 and 2019.
Use of Estimates, Policy [Policy Text Block]	of Estimates The consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles ("GAAP"), which requires management to make estimates and assumptions. These estimates, judgments and assumptions can affect the reported amounts in the financial statements and the footnotes thereto. Actual results could differ materially from these estimates. On an ongoing basis, we evaluate our estimates, assumptions and judgments. Significant estimates inherent to the preparation of financial statements include: revenue recognition; the allowances for doubtful accounts and sales returns; contract assets; internally developed software; goodwill and intangible assets; business combinations, including contingent consideration; and income taxes, including valuation allowance and uncertain tax positions. We base our estimates on historical experience, market participant fair value considerations, projected future cash flows, and various other factors that are believed to be reasonable under the circumstances. Actual amounts could differ significantly from these estimates.
Consolidation, Policy [Policy Text Block]	is of Consolidation The consolidated financial statements include the accounts Nuance and our subsidiaries. Intercompany transactions and balances have been eliminated.
Accounting Standards Update and Change in Accounting Principle [Table Text Block]	Rev
Business Combinations Policy [Policy Text Block]	iness Combinations We determine and allocate the purchase price of an acquired company to the tangible and intangible assets acquired and liabilities assumed as of the date of acquisition. Results of operations and cash flows of acquired companies are included in our operating results from the date of acquisition. The purchase price allocation process requires us to use significant estimates and assumptions, which include: • estimated fair values of intangible assets; • estimated fair values of legal performance commitments to customers, assumed from the acquiree under existing contractual obligations (classified as deferred revenue); • estimated fair values of stock awards assumed from the acquiree that are included in the purchase price; • estimated fair value of required payments under contingent consideration provisions; • estimated income tax assets and liabilities assumed from the acquiree; and • estimated fair value of pre-acquisition contingencies assumed from the acquiree. The fair value of any contingent consideration is established at the acquisition date and included in the total purchase price. The contingent consideration is then adjusted to fair value, with any measurement-period adjustment recorded against goodwill. Adjustments identified subsequent to the measurement period are recorded within Acquisition-related costs, net. While we use our best estimates and assumptions as part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the business combination date, our estimates and assumptions are inherently uncertain and subject to refinement. As a result, during the measurement period, which is generally one year from the acquisition date, any adjustment to the assets acquired and liabilities assumed is recorded against goodwill in the period in which the amount is determined. Any adjustment identified subsequent to the measurement period is included in operating results in the period in which the amount is determined.
Goodwill and Intangible Assets, Policy [Policy Text Block]	dwill Goodwill represents the excess of the purchase price in a business combination over the fair value of net tangible and intangible assets acquired. Goodwill and intangible assets with indefinite lives are not amortized, but rather the carrying amounts of these assets are assessed for impairment at least annually or whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Goodwill is tested for impairment annually on July 1, the first day of the fourth quarter of the fiscal year. Goodwill impairment, if any, is determined by comparing the reporting unit's fair value to its carrying value. An impairment loss is recognized in an amount equal to the excess of the reporting unit's carrying value over its fair value, up to the amount of goodwill allocated to the reporting unit. There was no goodwill impairment for fiscal year 2020. See Note 6 for the impairment charges recorded in fiscal year 2018. For the purpose of testing goodwill for impairment, all goodwill acquired in a business combination is assigned to one or more reporting units. A reporting unit represents an operating segment or a component within an operating segment for which discrete financial information is available and is regularly reviewed by segment management for performance assessment and resource allocation. Components of similar economic characteristics are aggregated into one reporting unit for the purpose of goodwill impairment assessment. Reporting units are identified annually and re-assessed periodically for recent acquisitions or any changes in segment reporting structure. Corporate assets and liabilities are allocated to each reporting unit based on the reporting unit’ revenue, total operating expenses or operating income as a percentage of the consolidated amounts. Corporate debt and other financial liabilities that are not directly attributable to the reporting unit's operations and would not be transferred to hypothetical purchasers of the reporting units are excluded from a reporting unit's carrying amount. The fair value of a reporting unit is generally determined using a combination of the income approach and the market approach, where the income approach is weighted 50% and the market approach 50%. For the income approach, fair value is determined based on the present value of estimated future after-tax cash flows, discounted at an appropriate risk-adjusted rate. We use our internal forecasts to estimate future after-tax cash flows and estimate the long-term growth rates based on our most recent views of the long-term outlook for each reporting unit. Actual results may differ from those assumed in our forecasts. We derive our discount rates using a capital asset pricing model and analyzing published rates for industries relevant to our reporting units to estimate the weighted average cost of capital. We adjust the discount rates for the risks and uncertainty inherent in the respective businesses and in our internally developed forecasts. For the market approach, we use a valuation technique in which values are derived based on valuation multiples of comparable publicly traded companies. We assess each valuation methodology based upon the relevance and availability of the data at the time we perform the valuation and weight the methodologies appropriately.
Long-lived Assets [Policy Text Block]	long-lived assets consist principally of technology, customer relationships, internally developed software, land, and building and equipment. Customer relationships are amortized over their estimated economic lives based on the pattern of economic benefits expected to be generated from the use of the asset. Other definite-lived assets are amortized over their estimated economic lives using the straight-line method. The remaining useful lives of long-lived assets are re-assessed periodically for any events and circumstances that may change the future cash flows expected to be generated from the long-lived asset or asset group. Internally developed software consists of capitalized costs incurred during the application development stage, which include costs related design of the software configuration and interfaces, coding, installation and testing. Costs incurred during the preliminary project stage and post-implementation stage are expensed as incurred. Internally developed software is amortized over the estimated useful life, commencing on the date when the asset is ready for its intended use. Land, building and equipment are stated at cost and depreciated over their estimated useful lives. Leasehold improvements are depreciated over the shorter of the related lease term or the estimated useful life. Depreciation is computed using the straight-line method. Repair and maintenance costs are expensed as incurred. The cost and related accumulated depreciation of sold or retired assets are removed from the accounts and any gain or loss is included in the results of operations for the period. Long-lived assets with definite lives are tested for impairment whenever events or changes in circumstances indicate the carrying value of a specific asset or asset group may not be recoverable. We assess the recoverability of long-lived assets with definite lives at the asset group level. Asset groups are determined based upon the lowest level for which identifiable cash flows are largely
Cash and Cash Equivalents, Policy [Policy Text Block]	h and Cash Equivalents Cash and cash equivalents consist of cash on hand, including money market funds and time deposits with original maturities of 90 days or less.
Investment, Policy [Policy Text Block]	ketable Securities Marketable securities consist of time deposits and high-quality corporate debt instruments with stated maturities of more than 90 days. Investments are classified as available-for-sale and are recorded on the balance sheet at fair value with unrealized gains or losses reported as a separate component of accumulated other comprehensive loss, net of tax.
Accounts Receivable [Policy Text Block]	ounts Receivable Allowances Allowances for Doubtful Accounts. We record allowances for doubtful accounts for the estimated probable losses on uncollectible accounts receivable. The allowance is based upon the credit worthiness of our customers, our historical experience, the age of the receivable and current market and economic conditions. Receivables are written off against these allowances in the period they are determined to be uncollectible. Allowances for Sales Returns. We reduce transaction price for estimated returns and other allowances that represent variable considerations based on historical experience and other relevant factors. The returns allowance is recorded as a reduction to revenue and accounts receivable at the time the related revenue is recorded. Receivables are written off against the allowance in the period the return is received. For the years ended September 30, 2020 , 2019 and 2018 , the activity related to accounts receivable allowances was as follows (dollars in thousands): Allowance for Doubtful Accounts Allowance for Sales Returns Balance at September 30, 2017 $ 11,106 $ 29,541 Bad debt provision 2,011 — Write-offs, net of recoveries (4,248 ) — Revenue adjustments, net (a) — (23,396 ) Balance at September 30, 2018 8,869 6,145 Bad debt provisions 2,375 — Write-offs, net of recoveries (1,447 ) — Revenue adjustments, net — (1,554 ) Balance at September 30, 2019 9,797 4,591 Bad debt provisions 2,117 — Write-offs, net of recoveries (799 ) — Revenue adjustments, net — (935 ) Balance at September 30, 2020 $ 11,115 $ 3,656 (a) The decrease in provisions was primarily due to the resolution of the reserves related to the 2017 Malware Incident.
Research and Development Expense, Policy [Policy Text Block]	Development Costs We expense software development costs, including costs to develop software products or the software component of products to be sold, leased, or marketed to external users, before technological feasibility is reached. Technological feasibility is typically reached shortly before the release of such products and as a result, development costs that meet the criteria for capitalization were not material for the periods presented. Software development costs also include costs to develop software to be used solely to meet internal needs and cloud-based applications used to deliver our services. We capitalize development costs related to these software applications once the preliminary project stage is complete and it is probable that the project will be completed, and the software will be used to perform the function intended. As of September 30, 2020 and 2019 , the net book value of capitalized internal-use software costs was $55.6 million and $26.3 million , respectively, which are included within Land, buildings and equipment, net.
Business Acquisition-Related Costs [Policy Text Block]	uisition-Related Costs, Net Acquisition-related costs, net include costs related to business and other acquisitions, including potential acquisitions. These costs consist of (i) transition and integration costs, including retention payments, transitional employee costs and earn-out payments, and other costs related to integration activities; (ii) professional service fees, including financial advisory, legal, accounting, and other outside services incurred in connection with acquisition activities, and disputes and regulatory matters related to acquired entities; and (iii) fair value adjustments to acquisition-related contingencies. The components of acquisition-related costs, net were as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Transition and integration costs $ 3,778 $ 7,568 $ 14,443 Professional service fees (23 ) 1,940 983 Acquisition-related adjustments (871 ) (1,543 ) (3,416 ) Total $ 2,884 $ 7,965 $ 12,010
Income Tax, Policy [Policy Text Block]	ome Taxes We account for income taxes using the asset and liability method, under which we recognize the amount of taxes payable or refundable for the current year and deferred tax assets and liabilities for the future tax consequences of events that have been recognized in our financial statements or tax returns. We measure current and deferred tax assets and liabilities based on provisions of enacted tax law. We evaluate the realization of our deferred tax assets based on all available evidence and establish a valuation allowance to reduce deferred tax assets when it is more likely than not that they will not be realized. We recognize the financial statement effects of a tax position when it is more likely than not that, based on technical merits, the position will be sustained upon examination. The tax benefits of the position recognized in the financial statements are then measured based on the largest amount of benefit that is greater than 50% likely to be realized upon settlement with a taxing authority. In addition, we recognize interest and penalties related to unrecognized tax benefits as a component of the income tax provision.
Comprehensive Income (Loss) [Policy Text Block]	prehensive Loss The components of accumulated other comprehensive loss, reflected in the consolidated statements of stockholders’ equity, consisted of the following (dollars in thousands): September 30, 2020 September 30, 2019 Foreign currency translation adjustment $ (110,110 ) $ (124,608 ) Net unrealized losses on post-retirement benefits (7,873 ) (8,296 ) Unrealized gain (loss) on marketable securities 65 131 Accumulated other comprehensive loss $ (117,918 ) $ (132,773 ) No income tax provisions or benefits are recorded for foreign currency translation adjustment as the undistributed earnings in our foreign subsidiaries are expected to be indefinitely reinvested.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Fo
Foreign Currency Transactions and Translations Policy [Policy Text Block]	eign Currency Translation The functional currency of a foreign subsidiary is generally the local currency. We translate the financial statements of foreign subsidiaries to U.S. dollars using month-end exchange rates for assets and liabilities, and average rates for the reporting period for revenues, costs, and expenses. We record translation gains and losses in accumulated other comprehensive loss as a component of stockholders’ equity. We record net foreign exchange transaction gains and losses resulting from the conversion of the transaction currency to the functional currency within in other expense, net . Foreign currency transaction gains (losses)for fiscal years 2020 , 2019 and 2018 were $1.3 million , $1.1 million and $(1.2) million , respectively.
Share-based Payment Arrangement [Policy Text Block]	Stock-Based Compensation Stock-based compensation primarily consists of restricted stock units with service, and market or performance conditions. Equity awards are measured at the fair market value of the underlying stock at the grant date. We recognize stock compensation expense ratably over the requisite service period and account for forfeitures based on our estimates. Shares are issued on the vesting dates net of the applicable statutory tax withholding to be paid by us on behalf of our employees. As a result, fewer shares are issued than the number of awards outstanding. We record a liability for the tax withholding to be paid by us as a reduction to additional paid-in capital. We record any income tax effect related to stock-based awards through the consolidated statements of operations. Excess tax benefits are recognized as deferred tax assets upon settlement and are subject to regular review for valuation allowance.
Earnings Per Share, Policy [Policy Text Block]	Basic net income or loss per share is computed using the weighted-average number of common shares outstanding during the period. Diluted net income or loss per share is computed using the weighted-average number of common shares, giving effect to potentially dilutive securities outstanding during the period. Potentially dilutive securities consist of stock options, restricted stock units, contingently issuable shares under earn-out agreements, and potential issuance of stock upon conversion of our convertible debentures, as more fully described in Note 10 . In the event of conversion, we are required to settle the principal amount of the convertible debentures, with any accrued and unpaid interest in cash, and may settle the conversion spread in either cash or common stock at our election. Therefore, only the shares of common stock potentially issuable upon conversion are included within the diluted common shares for the reporting period, during which our average stock price exceeds the conversion price.

Revenue Recognition (Policies)

Revenue Recognition (Policies)	12 Months Ended
	Sep. 30, 2020
Revenue Recognition [Abstract]
Revenue from Contract with Customer [Policy Text Block]	We derive revenue from the following sources: (1) hosting services, (2) software licenses, including royalties, (3) M&S, (4) professional services, and (5) sale of hardware. Revenue is reported net of applicable sales and use tax, value-added tax and other transaction taxes imposed on the related transaction including mandatory government charges that are passed through to our customers. We account for a contract when both parties have approved and committed to the contract, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and the collectability of the consideration is probable. The majority of our arrangements with customers typically contain multiple products and services. We account for individual products and services separately if they are distinct--that is, if a product or service is separately identifiable from other items in the contract and if a customer can benefit from it on its own or with other resources that are readily available to the customer. We recognize revenue after applying the following five steps: • identification of the contract, or contracts, with a customer; • identification of the performance obligations in the contract, including whether they are distinct within the context of the contract; • determination of the transaction price, including the constraint on variable consideration; • allocation of the transaction price to the performance obligations in the contract; and • recognition of revenue when, or as, performance obligations are satisfied. We allocate the transaction price of the arrangement based on the relative estimated SSP of each distinct performance obligation. In determining SSP, we maximize observable inputs and consider a number of data points, including: • the pricing of standalone sales (in the instances where available); • the pricing established by management when setting prices for deliverables that are intended to be sold on a standalone basis; • contractually stated prices for deliverables that are intended to be sold on a standalone basis; and • other pricing factors, such as the geographical region in which the products are sold, and expected discounts based on the customer size and type. We only include estimated amounts of variable consideration in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. We reduce transaction prices for estimated returns and other allowances that represent variable consideration under ASU No. 2014-09, "Revenue from Contracts with Customers: Topic 606" ("ASC 606"), which we estimate based on historical return experience and other relevant factors and record a reduction to revenue and accounts receivable. Other forms of contingent revenue or variable consideration are infrequent. Revenue is recognized when control of these products and services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those services. We assess the timing of the transfer of products or services to the customer as compared to the timing of payments to determine whether a significant financing component exists. In accordance with the practical expedient in ASC 606-10-32-18, we do not assess the existence of a significant financing component when the difference between payment and transfer of deliverables is a year or less. If the difference in timing arises for reasons other than the provision of financing to either the customer or us, no financing component is deemed to exist. The primary purpose of our invoicing terms is to provide customers with simplified and predictable ways of purchasing our services, not to receive or provide financing from or to customers. We do not consider set-up fees nor other upfront fees paid by our customers to represent a financing component. Certain products are sold through distributors or resellers. Certain distributors and resellers have been granted right of return and selling incentives which are accounted for as variable consideration when estimating the amount of revenue to be recognized. Returns and credits are estimated at the contract inception and updated at the end of each reporting period as additional information becomes available. In accordance with the practical expedient in ASC 606-10-10-4, we apply a portfolio approach to estimate the variable consideration associated with this group of customers. Reimbursements for out-of-pocket costs generally include, but are not limited to, costs related to transportation, lodging and meals. Revenue from reimbursed out-of-pocket costs is accounted for as variable consideration. Shipping and handling activities are not considered a contract performance obligation. We record shipping and handling costs billed to customers as revenue with offsetting costs recorded as cost of revenue. Performance Obligations Hosting Hosting services, which allow our customers to use the hosted software over the contract period without taking possession of the software, are provided on a usage basis as consumed or on a fixed fee subscription basis. Our hosting contract terms generally range from one to five years. As each day of providing services is substantially the same and the customer simultaneously receives and consumes the benefits as access is provided, we have determined that our hosting services arrangements are a single performance obligation comprised of a series of distinct services. These services include variable consideration, which is typically a function of usage. We recognize revenue as each distinct service period is performed (i.e., recognized as incurred). Subscription-based revenue represents a single promise to stand-ready to provide access to our hosting services. Revenue is recognized over time on a ratable basis over the hosting contract term, which generally ranges from one to five years. Software Licenses On-premise software licenses sold with non-distinct professional services to customize and/or integrate the underlying software are accounted for as a combined performance obligation. Revenue from the combined performance obligation is recognized over time based upon the progress towards completion of the project, which is measured based on the labor hours already incurred to date as compared to the total estimated labor hours. Revenue from distinct on-premise software licenses, which do not require professional services to customize and/or integrate the software license, is recognized at the point in time when the software is made available to the customer and control is transferred. Revenue from software licenses sold on a royalty basis, where the license of intellectual property is the predominant item to which the royalty relates, is recognized in the period the usage occurs in accordance with the practical expedient in ASC 606-10-55-65(A). Maintenance and Support Our M&S contracts generally include telephone support and the right to receive unspecified upgrades and updates on a when-and-if available basis. M&S revenue is recognized over time on a ratable basis over the contract period because we transfer control evenly by providing a stand-ready service. Professional Services Revenue from distinct professional services, including training, is recognized over time based upon the progress towards completion of the project, which is measured based on the labor hours already incurred to date as compared to the total estimated labor hours. Hardware Hardware revenue is recognized at the point in time when control is transferred to the customer, which is typically upon delivery. Significant Judgments Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Our license contracts often include professional services to customize and/or integrate the licenses into the customer’s environment. Judgment is required to determine whether the license is considered distinct and accounted for separately, or not distinct and accounted for together with professional services. Judgments are required to determine the SSP for each distinct performance obligation. When SSP is directly observable, we estimate SSP based upon the historical transaction prices, adjusted for geographic considerations, customer classes, and customer relationship profiles. In instances where SSP is not directly observable, we determine SSP using information that may include market conditions and other observable inputs. We may have more than one SSP for individual products and services due to the stratification of those products and services by customers and circumstances. In these instances, we may use information such as the size of the customer and geographic region in determining SSP. Determining SSP for performance obligations which we never sell separately also requires significant judgment. In estimating the SSP for such performance obligations, we consider the likely price that would have resulted from established pricing practices had the deliverable been offered separately and the prices a customer would likely be willing to pay. From time to time, we may enter into arrangements with third party suppliers to resell products or services. In such cases, we evaluate whether we are the principal (i.e. report revenues on a gross basis) or agent (i.e. report revenues on a net basis). In doing so, we first evaluate whether we control the good or service before it is transferred to the customer. If we control the good or service before it is transferred to the customer, we are the principal; if not, we are the agent. Generally, we control a promised good or service before transferring that good or service to the customer and act as the principal to the transaction. Determining whether we control the good or service before it is transferred to the customer may require judgment. Disaggregated Revenue We disaggregate revenue from contracts with customers by the reportable segment, products, and services provided. The following presentation depicts the timing, risks, and uncertainty of our revenue streams, which is also in line with how we manage our businesses, assess performance, and determine management compensation. Our disaggregated revenue from continuing operations is as follows (dollars in thousands): For the Year Ended September 30, 2020 Hosting and professional services Product and licensing Maintenance and support Total Healthcare $ 577,787 $ 201,207 $ 136,338 $ 915,332 Enterprise 319,347 89,950 120,380 529,677 Other 28,910 4,970 10 33,890 Total revenues $ 926,044 $ 296,127 $ 256,728 $ 1,478,899 For the Year Ended September 30, 2019 Hosting and professional services Product and licensing Maintenance and support Total Healthcare $ 546,037 $ 246,788 $ 156,905 $ 949,730 Enterprise 316,247 82,073 111,758 510,078 Other 51,359 9,832 272 61,463 Total revenues $ 913,643 $ 338,693 $ 268,935 $ 1,521,271 Hardware revenue comprised approximately $28.0 million of total product and licensing revenue for fiscal year 2020 and $30.0 million for fiscal year 2019. Contract Acquisition Costs We are required to capitalize certain contract acquisition costs under ASC 606. The capitalized costs primarily relate to paid commissions and other direct, incremental costs to acquire customer contracts. In accordance with the practical expedient in ASC 606-10-10-4, we apply a portfolio approach to estimate contract acquisition costs for groups of customer contracts. We elect to apply the practical expedient in ASC 340-40-25-4 and will expense contract acquisition costs as incurred where the expected period of benefit is one year or less. Sales commissions paid on renewal maintenance and support are not commensurate with sales commissions paid on the initial maintenance and support contract. Contract acquisition costs are deferred and amortized on a straight-line basis over the period of benefit, which we have estimated to be between one and five years. The period of benefit was determined based on an average customer contract term, expected contract renewals, changes in technology and our ability to retain customers including canceled contracts. Contract acquisition costs are classified as current or noncurrent assets based on when the expense will be recognized. The current and noncurrent portions of contract acquisition costs are included in Prepaid expenses and other current assets, and Other assets, respectively. As of September 30, 2020, we had $22.5 million of current contract acquisition costs and $54.1 million of noncurrent contract acquisition costs. As of September 30, 2019, we had $19.9 million of current contract acquisition costs and $30.1 million of noncurrent contract acquisition costs. Commission expense is primarily included in Sales and marketing expense on the consolidated statements of operations. We also had amortization expense of $18.5 million and $15.5 million related to contract acquisition costs for the year ended September 30, 2020 and 2019. There was no impairment related to commission costs capitalized. Capitalized Contract Costs We capitalize incremental costs incurred to fulfill our contracts that (1) relate directly to the contract, (2) are expected to generate resources that will be used to satisfy our performance obligation under the contract, and (3) are expected to be recovered through revenue generated under the contract. Our capitalized costs consist primarily of setup costs, such as costs to standup, customize, and develop applications for each customer. These costs are incurred to satisfy our stand-ready obligation to provide access to our connected offerings. The contract costs are expensed to cost of revenue as we satisfy our stand-ready obligation over the contract term, which we estimate to be between one and five years. The contract term estimation was determined based on an average customer contract term, expected contract renewals, changes in technology, and our ability to retain customers including canceled contracts. We classify capitalized contract costs as current or noncurrent based on the timing of when we expect to recognize the expense. The current and noncurrent portions of capitalized contract fulfillment costs are included in Prepaid expenses and other current assets, and Other assets, respectively. At September 30, 2020, we had $18.5 million of short-term contract costs included with Prepaid expenses and other current assets and $32.8 million of long-term costs included within Other assets. As of September 30, 2019, we had $17.2 million of short-term contract costs included with Prepaid expenses and other current assets and $38.5 million of long-term costs included within Other assets. Trade Accounts Receivable and Contract Balances We classify our right to consideration in exchange for deliverables as either a receivable or a contract asset. A receivable is a right to consideration that is unconditional (i.e. only the passage of time is required before payment is due). We present such receivables in Accounts receivable, net in our consolidated balance sheets at their net estimated realizable value. We maintain an allowance for doubtful accounts to provide for the estimated amount of receivables that may not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables and other applicable factors. Our contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. Contract assets include unbilled amounts from long-term contracts when revenue recognized exceeds the amount billed to the customer, and right to payment is not solely subject to the passage of time. The current and noncurrent portions of contract assets are included in Prepaid expenses and other current assets, and Other assets. As of September 30, 2020, we had $49.3 million of current contract assets and $109.9 million of noncurrent contract assets. As of September 30, 2019, we had $58.7 million of current contract assets and $108.7 million of noncurrent contract assets. The table below shows significant changes in contract assets of continuing operations (dollars in thousands): Contract assets Balance September 30, 2019 $ 167,324 Revenues recognized but not billed 286,242 Amounts reclassified to accounts receivable (294,315 ) Balance September 30, 2020 $ 159,251 Our contract liabilities, or Deferred revenue, consist of advance payments and billings in excess of revenues recognized. We classify Deferred revenue as current or noncurrent based on when we expect to recognize the revenues. The table below shows significant changes in Deferred revenue of continuing operations (dollars in thousands): Deferred revenue Balance September 30, 2019 $ 348,006 Amounts bill but not recognized 819,049 Revenue recognized (801,423 ) Balance September 30, 2020 $ 365,632 Remaining Performance Obligations The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied or partially unsatisfied at September 30, 2020 (dollars in thousands): Within One Year Two to Four Years Greater than Four Years Total Total revenue $ 708,343 $ 963,223 $ 62,872 $ 1,734,438
Revenue from Contract with Customer [Text Block]	3 . Revenue Recognition We derive revenue from the following sources: (1) hosting services, (2) software licenses, including royalties, (3) M&S, (4) professional services, and (5) sale of hardware. Revenue is reported net of applicable sales and use tax, value-added tax and other transaction taxes imposed on the related transaction including mandatory government charges that are passed through to our customers. We account for a contract when both parties have approved and committed to the contract, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and the collectability of the consideration is probable. The majority of our arrangements with customers typically contain multiple products and services. We account for individual products and services separately if they are distinct--that is, if a product or service is separately identifiable from other items in the contract and if a customer can benefit from it on its own or with other resources that are readily available to the customer. We recognize revenue after applying the following five steps: • identification of the contract, or contracts, with a customer; • identification of the performance obligations in the contract, including whether they are distinct within the context of the contract; • determination of the transaction price, including the constraint on variable consideration; • allocation of the transaction price to the performance obligations in the contract; and • recognition of revenue when, or as, performance obligations are satisfied. We allocate the transaction price of the arrangement based on the relative estimated SSP of each distinct performance obligation. In determining SSP, we maximize observable inputs and consider a number of data points, including: • the pricing of standalone sales (in the instances where available); • the pricing established by management when setting prices for deliverables that are intended to be sold on a standalone basis; • contractually stated prices for deliverables that are intended to be sold on a standalone basis; and • other pricing factors, such as the geographical region in which the products are sold, and expected discounts based on the customer size and type. We only include estimated amounts of variable consideration in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. We reduce transaction prices for estimated returns and other allowances that represent variable consideration under ASU No. 2014-09, "Revenue from Contracts with Customers: Topic 606" ("ASC 606"), which we estimate based on historical return experience and other relevant factors and record a reduction to revenue and accounts receivable. Other forms of contingent revenue or variable consideration are infrequent. Revenue is recognized when control of these products and services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those services. We assess the timing of the transfer of products or services to the customer as compared to the timing of payments to determine whether a significant financing component exists. In accordance with the practical expedient in ASC 606-10-32-18, we do not assess the existence of a significant financing component when the difference between payment and transfer of deliverables is a year or less. If the difference in timing arises for reasons other than the provision of financing to either the customer or us, no financing component is deemed to exist. The primary purpose of our invoicing terms is to provide customers with simplified and predictable ways of purchasing our services, not to receive or provide financing from or to customers. We do not consider set-up fees nor other upfront fees paid by our customers to represent a financing component. Certain products are sold through distributors or resellers. Certain distributors and resellers have been granted right of return and selling incentives which are accounted for as variable consideration when estimating the amount of revenue to be recognized. Returns and credits are estimated at the contract inception and updated at the end of each reporting period as additional information becomes available. In accordance with the practical expedient in ASC 606-10-10-4, we apply a portfolio approach to estimate the variable consideration associated with this group of customers. Reimbursements for out-of-pocket costs generally include, but are not limited to, costs related to transportation, lodging and meals. Revenue from reimbursed out-of-pocket costs is accounted for as variable consideration. Shipping and handling activities are not considered a contract performance obligation. We record shipping and handling costs billed to customers as revenue with offsetting costs recorded as cost of revenue. Performance Obligations Hosting Hosting services, which allow our customers to use the hosted software over the contract period without taking possession of the software, are provided on a usage basis as consumed or on a fixed fee subscription basis. Our hosting contract terms generally range from one to five years. As each day of providing services is substantially the same and the customer simultaneously receives and consumes the benefits as access is provided, we have determined that our hosting services arrangements are a single performance obligation comprised of a series of distinct services. These services include variable consideration, which is typically a function of usage. We recognize revenue as each distinct service period is performed (i.e., recognized as incurred). Subscription-based revenue represents a single promise to stand-ready to provide access to our hosting services. Revenue is recognized over time on a ratable basis over the hosting contract term, which generally ranges from one to five years. Software Licenses On-premise software licenses sold with non-distinct professional services to customize and/or integrate the underlying software are accounted for as a combined performance obligation. Revenue from the combined performance obligation is recognized over time based upon the progress towards completion of the project, which is measured based on the labor hours already incurred to date as compared to the total estimated labor hours. Revenue from distinct on-premise software licenses, which do not require professional services to customize and/or integrate the software license, is recognized at the point in time when the software is made available to the customer and control is transferred. Revenue from software licenses sold on a royalty basis, where the license of intellectual property is the predominant item to which the royalty relates, is recognized in the period the usage occurs in accordance with the practical expedient in ASC 606-10-55-65(A). Maintenance and Support Our M&S contracts generally include telephone support and the right to receive unspecified upgrades and updates on a when-and-if available basis. M&S revenue is recognized over time on a ratable basis over the contract period because we transfer control evenly by providing a stand-ready service. Professional Services Revenue from distinct professional services, including training, is recognized over time based upon the progress towards completion of the project, which is measured based on the labor hours already incurred to date as compared to the total estimated labor hours. Hardware Hardware revenue is recognized at the point in time when control is transferred to the customer, which is typically upon delivery. Significant Judgments Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Our license contracts often include professional services to customize and/or integrate the licenses into the customer’s environment. Judgment is required to determine whether the license is considered distinct and accounted for separately, or not distinct and accounted for together with professional services. Judgments are required to determine the SSP for each distinct performance obligation. When SSP is directly observable, we estimate SSP based upon the historical transaction prices, adjusted for geographic considerations, customer classes, and customer relationship profiles. In instances where SSP is not directly observable, we determine SSP using information that may include market conditions and other observable inputs. We may have more than one SSP for individual products and services due to the stratification of those products and services by customers and circumstances. In these instances, we may use information such as the size of the customer and geographic region in determining SSP. Determining SSP for performance obligations which we never sell separately also requires significant judgment. In estimating the SSP for such performance obligations, we consider the likely price that would have resulted from established pricing practices had the deliverable been offered separately and the prices a customer would likely be willing to pay. From time to time, we may enter into arrangements with third party suppliers to resell products or services. In such cases, we evaluate whether we are the principal (i.e. report revenues on a gross basis) or agent (i.e. report revenues on a net basis). In doing so, we first evaluate whether we control the good or service before it is transferred to the customer. If we control the good or service before it is transferred to the customer, we are the principal; if not, we are the agent. Generally, we control a promised good or service before transferring that good or service to the customer and act as the principal to the transaction. Determining whether we control the good or service before it is transferred to the customer may require judgment. Disaggregated Revenue We disaggregate revenue from contracts with customers by the reportable segment, products, and services provided. The following presentation depicts the timing, risks, and uncertainty of our revenue streams, which is also in line with how we manage our businesses, assess performance, and determine management compensation. Our disaggregated revenue from continuing operations is as follows (dollars in thousands): For the Year Ended September 30, 2020 Hosting and professional services Product and licensing Maintenance and support Total Healthcare $ 577,787 $ 201,207 $ 136,338 $ 915,332 Enterprise 319,347 89,950 120,380 529,677 Other 28,910 4,970 10 33,890 Total revenues $ 926,044 $ 296,127 $ 256,728 $ 1,478,899 For the Year Ended September 30, 2019 Hosting and professional services Product and licensing Maintenance and support Total Healthcare $ 546,037 $ 246,788 $ 156,905 $ 949,730 Enterprise 316,247 82,073 111,758 510,078 Other 51,359 9,832 272 61,463 Total revenues $ 913,643 $ 338,693 $ 268,935 $ 1,521,271 Hardware revenue comprised approximately $28.0 million of total product and licensing revenue for fiscal year 2020 and $30.0 million for fiscal year 2019. Contract Acquisition Costs We are required to capitalize certain contract acquisition costs under ASC 606. The capitalized costs primarily relate to paid commissions and other direct, incremental costs to acquire customer contracts. In accordance with the practical expedient in ASC 606-10-10-4, we apply a portfolio approach to estimate contract acquisition costs for groups of customer contracts. We elect to apply the practical expedient in ASC 340-40-25-4 and will expense contract acquisition costs as incurred where the expected period of benefit is one year or less. Sales commissions paid on renewal maintenance and support are not commensurate with sales commissions paid on the initial maintenance and support contract. Contract acquisition costs are deferred and amortized on a straight-line basis over the period of benefit, which we have estimated to be between one and five years. The period of benefit was determined based on an average customer contract term, expected contract renewals, changes in technology and our ability to retain customers including canceled contracts. Contract acquisition costs are classified as current or noncurrent assets based on when the expense will be recognized. The current and noncurrent portions of contract acquisition costs are included in Prepaid expenses and other current assets, and Other assets, respectively. As of September 30, 2020, we had $22.5 million of current contract acquisition costs and $54.1 million of noncurrent contract acquisition costs. As of September 30, 2019, we had $19.9 million of current contract acquisition costs and $30.1 million of noncurrent contract acquisition costs. Commission expense is primarily included in Sales and marketing expense on the consolidated statements of operations. We also had amortization expense of $18.5 million and $15.5 million related to contract acquisition costs for the year ended September 30, 2020 and 2019. There was no impairment related to commission costs capitalized. Capitalized Contract Costs We capitalize incremental costs incurred to fulfill our contracts that (1) relate directly to the contract, (2) are expected to generate resources that will be used to satisfy our performance obligation under the contract, and (3) are expected to be recovered through revenue generated under the contract. Our capitalized costs consist primarily of setup costs, such as costs to standup, customize, and develop applications for each customer. These costs are incurred to satisfy our stand-ready obligation to provide access to our connected offerings. The contract costs are expensed to cost of revenue as we satisfy our stand-ready obligation over the contract term, which we estimate to be between one and five years. The contract term estimation was determined based on an average customer contract term, expected contract renewals, changes in technology, and our ability to retain customers including canceled contracts. We classify capitalized contract costs as current or noncurrent based on the timing of when we expect to recognize the expense. The current and noncurrent portions of capitalized contract fulfillment costs are included in Prepaid expenses and other current assets, and Other assets, respectively. At September 30, 2020, we had $18.5 million of short-term contract costs included with Prepaid expenses and other current assets and $32.8 million of long-term costs included within Other assets. As of September 30, 2019, we had $17.2 million of short-term contract costs included with Prepaid expenses and other current assets and $38.5 million of long-term costs included within Other assets. Trade Accounts Receivable and Contract Balances We classify our right to consideration in exchange for deliverables as either a receivable or a contract asset. A receivable is a right to consideration that is unconditional (i.e. only the passage of time is required before payment is due). We present such receivables in Accounts receivable, net in our consolidated balance sheets at their net estimated realizable value. We maintain an allowance for doubtful accounts to provide for the estimated amount of receivables that may not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables and other applicable factors. Our contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. Contract assets include unbilled amounts from long-term contracts when revenue recognized exceeds the amount billed to the customer, and right to payment is not solely subject to the passage of time. The current and noncurrent portions of contract assets are included in Prepaid expenses and other current assets, and Other assets. As of September 30, 2020, we had $49.3 million of current contract assets and $109.9 million of noncurrent contract assets. As of September 30, 2019, we had $58.7 million of current contract assets and $108.7 million of noncurrent contract assets. The table below shows significant changes in contract assets of continuing operations (dollars in thousands): Contract assets Balance September 30, 2019 $ 167,324 Revenues recognized but not billed 286,242 Amounts reclassified to accounts receivable (294,315 ) Balance September 30, 2020 $ 159,251 Our contract liabilities, or Deferred revenue, consist of advance payments and billings in excess of revenues recognized. We classify Deferred revenue as current or noncurrent based on when we expect to recognize the revenues. The table below shows significant changes in Deferred revenue of continuing operations (dollars in thousands): Deferred revenue Balance September 30, 2019 $ 348,006 Amounts bill but not recognized 819,049 Revenue recognized (801,423 ) Balance September 30, 2020 $ 365,632 Remaining Performance Obligations The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied or partially unsatisfied at September 30, 2020 (dollars in thousands): Within One Year Two to Four Years Greater than Four Years Total Total revenue $ 708,343 $ 963,223 $ 62,872 $ 1,734,438

Recent Issued Accounting Pronou

Recent Issued Accounting Pronouncement (Tables)	12 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Allowance for Doubtful Accounts and Sales Returns [Table Text Block]	the years ended September 30, 2020 , 2019 and 2018 , the activity related to accounts receivable allowances was as follows (dollars in thousands): Allowance for Doubtful Accounts Allowance for Sales Returns Balance at September 30, 2017 $ 11,106 $ 29,541 Bad debt provision 2,011 — Write-offs, net of recoveries (4,248 ) — Revenue adjustments, net (a) — (23,396 ) Balance at September 30, 2018 8,869 6,145 Bad debt provisions 2,375 — Write-offs, net of recoveries (1,447 ) — Revenue adjustments, net — (1,554 ) Balance at September 30, 2019 9,797 4,591 Bad debt provisions 2,117 — Write-offs, net of recoveries (799 ) — Revenue adjustments, net — (935 ) Balance at September 30, 2020 $ 11,115 $ 3,656 (a) The decrease in provisions was primarily due to the resolution of the reserves related to the 2017 Malware Incident.
Components of Accumulated Other Comprehensive Income	components of accumulated other comprehensive loss, reflected in the consolidated statements of stockholders’ equity, consisted of the following (dollars in thousands): September 30, 2020 September 30, 2019 Foreign currency translation adjustment $ (110,110 ) $ (124,608 ) Net unrealized losses on post-retirement benefits (7,873 ) (8,296 ) Unrealized gain (loss) on marketable securities 65 131 Accumulated other comprehensive loss $ (117,918 ) $ (132,773 ) No income tax provisions or benefits are recorded for foreign currency translation adjustment as the undistributed earnings in our foreign subsidiaries are expected to be indefinitely reinvested.

Revenue Recognition Revenue fro

Revenue Recognition Revenue from Contract with Customers (Tables)	12 Months Ended
	Sep. 30, 2020
Revenue Recognition [Abstract]
Disaggregation of Revenue [Table Text Block]	Disaggregated Revenue We disaggregate revenue from contracts with customers by the reportable segment, products, and services provided. The following presentation depicts the timing, risks, and uncertainty of our revenue streams, which is also in line with how we manage our businesses, assess performance, and determine management compensation. Our disaggregated revenue from continuing operations is as follows (dollars in thousands): For the Year Ended September 30, 2020 Hosting and professional services Product and licensing Maintenance and support Total Healthcare $ 577,787 $ 201,207 $ 136,338 $ 915,332 Enterprise 319,347 89,950 120,380 529,677 Other 28,910 4,970 10 33,890 Total revenues $ 926,044 $ 296,127 $ 256,728 $ 1,478,899

Revenue Recognition Contract As

Revenue Recognition Contract Assets (Tables)	12 Months Ended
	Sep. 30, 2020
Contract Assets [Abstract]
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]	The table below shows significant changes in Deferred revenue of continuing operations (dollars in thousands): Deferred revenue Balance September 30, 2019 $ 348,006 Amounts bill but not recognized 819,049 Revenue recognized (801,423 ) Balance September 30, 2020 $ 365,632 Contract assets Balance September 30, 2019 $ 167,324 Revenues recognized but not billed 286,242 Amounts reclassified to accounts receivable (294,315 ) Balance September 30, 2020 $ 159,251

Revenue Recognition Contract Li

Revenue Recognition Contract Liabilities (Tables)	12 Months Ended
	Sep. 30, 2020
Contract Liabilities [Abstract]
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]	The table below shows significant changes in Deferred revenue of continuing operations (dollars in thousands): Deferred revenue Balance September 30, 2019 $ 348,006 Amounts bill but not recognized 819,049 Revenue recognized (801,423 ) Balance September 30, 2020 $ 365,632 Contract assets Balance September 30, 2019 $ 167,324 Revenues recognized but not billed 286,242 Amounts reclassified to accounts receivable (294,315 ) Balance September 30, 2020 $ 159,251

Revenue Recognition Revenue, Re

Revenue Recognition Revenue, Remaining Performance Obligation (Tables)	12 Months Ended
	Sep. 30, 2020
Revenue, Remaining Performance Obligation [Abstract]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	Remaining Performance Obligations The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied or partially unsatisfied at September 30, 2020 (dollars in thousands): Within One Year Two to Four Years Greater than Four Years Total Total revenue $ 708,343 $ 963,223 $ 62,872 $ 1,734,438 The table above includes fixed backlogs and does not include variable backlog derived from contingent usage-based activities, such as royalties and usage-based hosting revenue.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill for our reportable segments for fiscal years 2020 and 2019 were as follows (dollars in thousands): Healthcare Enterprise Other Total Balance as of September 30, 2018 $ 1,430,325 $ 683,347 $ 13,487 $ 2,127,159 Acquisitions 8,785 — — 8,785 Purchase accounting adjustments 113 — — 113 Effect of foreign currency translation (4,079 ) (3,444 ) (638 ) (8,161 ) Balance as of September 30, 2019 1,435,144 679,903 12,849 2,127,896 Purchase accounting adjustments (31 ) — — (31 ) Effect of foreign currency translation 3,063 2,697 87 5,847 Balance as of September 30, 2020 $ 1,438,176 $ 682,600 $ 12,936 $ 2,133,712
Intangible Assets	Intangible assets consist of the following as of September 30, 2020 and 2019 (dollars in thousands): September 30, 2020 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Life (Years) Customer relationships $ 523,042 $ (360,617 ) $ 162,425 4.4 Technology and patents 205,451 (154,926 ) 50,525 3.1 Trade names, trademarks, and other 28,969 (28,435 ) 534 0.9 Total $ 757,462 $ (543,978 ) $ 213,484 September 30, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Life (Years) Customer relationships $ 500,953 $ (292,127 ) $ 208,826 5.3 Technology and patents 147,394 (69,259 ) 78,135 3.8 Trade names, trademarks, and other 28,961 (24,551 ) 4,410 1.2 Total $ 677,308 $ (385,937 ) $ 291,371
Estimated Amortization Expense	Estimated amortization expense for each of the five succeeding years as of September 30, 2020 , is as follows (dollars in thousands): Year Ending September 30, Cost of Revenue Other Operating Expenses Total 2021 $ 16,994 $ 43,036 $ 60,030 2022 16,272 39,788 56,060 2023 12,323 33,680 46,003 2024 4,936 20,074 25,010 2025 — 19,032 19,032 Thereafter — 7,349 7,349 Total $ 50,525 $ 162,959 $ 213,484

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Sep. 30, 2020
Receivables [Abstract]
Accounts Receivable, Excluding Acquired Unbilled Accounts Receivable	Accounts receivable, net consisted of the following (dollars in thousands): September 30, 2020 September 30, 2019 (ASC 606) (ASC 606) Accounts receivable, gross $ 215,347 $ 255,061 Less: allowance for doubtful accounts (11,115 ) (9,797 ) Less: allowance for sales returns (3,656 ) (4,591 ) Accounts receivable, net $ 200,576 $ 240,673

Land, Building and Equipment,_2

Land, Building and Equipment, Net (Tables)	12 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Land, Building and Equipment, Net	Land, building and equipment, net consisted of the following (dollars in thousands): Useful Life (In Years) September 30, 2020 September 30, 2019 Land — $ 2,400 $ 2,400 Building 30 6,741 6,696 Machinery and equipment 3-5 156,454 159,681 Computers, software and equipment 3-5 157,000 131,012 Leasehold improvements 2-15 32,988 26,244 Furniture and fixtures 5-7 11,217 14,455 Construction in progress — 41,694 20,708 Subtotal 408,494 361,196 Less: accumulated depreciation (265,066 ) (239,993 ) Land, building and equipment, net $ 143,428 $ 121,203

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Sep. 30, 2020
Accrued Liabilities, Current [Abstract]
Accrued Expenses	Accrued expenses and other current liabilities consisted of the following (dollars in thousands): September 30, 2020 September 30, 2019 Compensation $ 117,963 $ 119,412 Accrued interest payable 13,484 19,302 Cost of revenue related liabilities 29,953 58,012 Consulting and professional fees 10,857 20,401 Deferred rent liabilities — 2,503 Sales and marketing incentives 2,021 2,692 Sales and other taxes payable 6,339 8,089 ASC 842 operating lease obligations 28,273 — Other 4,374 19,159 Total $ 213,264 $ 249,570

Credit Facilities and Debt (Tab

Credit Facilities and Debt (Tables)	12 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Borrowing Obligations	At September 30, 2020 and 2019 , we had the following borrowing obligations (dollars in thousands): September 30, 2020 September 30, 2019 5.625% Senior Notes due 2026, net of deferred issuance costs of $3.9 million and $4.5 million, respectively. Effective interest rate 5.625%. $ 496,148 $ 495,518 6.000% Senior Notes due 2024, net of deferred issuance costs of $1.5 million. Effective interest rate 6.000%. — 298,529 1.00% Convertible Debentures due 2035, net of unamortized discount of $64.8 million and $91.6 million, respectively, and deferred issuance costs of $2.9 million and $4.3 million, respectively. Effective interest rate 5.622%. 608,767 580,639 2.75% Convertible Debentures due 2031. Effective interest rate 7.432%. — 46,568 1.25% Convertible Debentures due 2025, net of unamortized discount of $45.2 million and $71.6 million, respectively, and deferred issuance costs of $1.9 million and $3.1 million, respectively. Effective interest rate 5.578%. 215,582 275,257 1.50% Convertible Debentures due 2035, net of unamortized discount of $10.4 million and $22.7 million, respectively, and deferred issuance costs of $0.3 million and $0.8 million, respectively. Effective interest rate 5.394%. 216,627 240,406 Deferred issuance costs related to our Revolving Credit Facility. (451 ) (511 ) Total debt 1,536,673 1,936,406 Less: current portion (a) (432,209 ) (1,142,870 ) Total long-term debt $ 1,104,464 $ 793,536
Applicable Margin for Borrowings	At September 30, 2020 and 2019 , we had the following borrowing obligations (dollars in thousands): September 30, 2020 September 30, 2019 5.625% Senior Notes due 2026, net of deferred issuance costs of $3.9 million and $4.5 million, respectively. Effective interest rate 5.625%. $ 496,148 $ 495,518 6.000% Senior Notes due 2024, net of deferred issuance costs of $1.5 million. Effective interest rate 6.000%. — 298,529 1.00% Convertible Debentures due 2035, net of unamortized discount of $64.8 million and $91.6 million, respectively, and deferred issuance costs of $2.9 million and $4.3 million, respectively. Effective interest rate 5.622%. 608,767 580,639 2.75% Convertible Debentures due 2031. Effective interest rate 7.432%. — 46,568 1.25% Convertible Debentures due 2025, net of unamortized discount of $45.2 million and $71.6 million, respectively, and deferred issuance costs of $1.9 million and $3.1 million, respectively. Effective interest rate 5.578%. 215,582 275,257 1.50% Convertible Debentures due 2035, net of unamortized discount of $10.4 million and $22.7 million, respectively, and deferred issuance costs of $0.3 million and $0.8 million, respectively. Effective interest rate 5.394%. 216,627 240,406 Deferred issuance costs related to our Revolving Credit Facility. (451 ) (511 ) Total debt 1,536,673 1,936,406 Less: current portion (a) (432,209 ) (1,142,870 ) Total long-term debt $ 1,104,464 $ 793,536
Annual Aggregate Principal Term Loans to be Repaid	The following table summarizes the maturities of our borrowing obligations as of September 30, 2020 (dollars in thousands): Fiscal Year Convertible Debentures (1) Senior Notes Total 2021 $ 490,051 $ — $ 490,051 2022 — — — 2023 676,488 — 676,488 2024 — — — 2025 — — — Thereafter — 500,000 500,000 Total before unamortized discount 1,166,539 500,000 1,666,539 Less: unamortized discount and issuance costs (125,563 ) (4,303 ) (129,866 ) Total debt $ 1,040,976 $ 495,697 $ 1,536,673 (1) The repayment schedule above assumes that payment is due on the first contractual redemption date after September 30, 2020 . As more fully described below, as of September 30, 2020 , the holders had the right to convert all or any portion of the 1.25% 2025 Debentures and 1.5% 2035 Debentures between October 1, 2020 and December 31, 2020. As a result, the net carrying amounts of these two convertible notes were included in current liabilities as of September 30, 2020 .

Financial Instruments and Hed_2

Financial Instruments and Hedging Activities (Tables)	12 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Quantitative Summary of Fair Value of Hedged and Non-Hedged Instruments	summary of our derivative instruments is as follows (dollars in thousands): Fair Value Derivatives Not Designated as Hedges: Balance Sheet Classification September 30, 2020 September 30, 2019 Foreign currency forward contracts Prepaid expenses and other current assets $ 109 $ 597 Foreign currency forward contracts Accrued expenses and other current liabilities $ (92 ) $ (327 )
Summarized Activity of Derivative Instruments	(dollars in thousands): Income Statement Classification Income (loss) recognized Year Ended September 30, Derivatives Not Designated as Hedges: 2020 2019 2018 Foreign currency forward contracts Other income (expense), net $ 379 $ 1,816 $ (3,616 )

Fair Value Measures (Tables)

Fair Value Measures (Tables)	12 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	September 30, 2020 and 2019 consisted of (dollars in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total Assets: Money market funds (a) $ 182,645 $ — $ — $ 182,645 Time deposits (b) — 95,180 — 95,180 Commercial paper, $33,265 at cost (b) — 33,290 — 33,290 Corporate notes and bonds, $15,460 at cost (b) — 15,480 — 15,480 Foreign currency exchange contracts (b) — 109 — 109 Total assets at fair value $ 182,645 $ 144,059 $ — $ 326,704 Liabilities: Foreign currency exchange contracts (b) $ — $ (92 ) $ — $ (92 ) Contingent acquisition payments (c) — — (1,796 ) (1,796 ) Total liabilities at fair value $ — $ (92 ) $ (1,796 ) $ (1,888 ) September 30, 2019 Level 1 Level 2 Level 3 Total Assets: Money market funds (a) $ 217,861 $ — $ — $ 217,861 Time deposits (b) — 115,913 — 115,913 Commercial paper, $77,089 at cost (b) — 77,494 — 77,494 Corporate notes and bonds, $37,504 at cost (b) — 37,566 — 37,566 Foreign currency exchange contracts (b) — 597 — 597 Total assets at fair value $ 217,861 $ 231,570 $ — $ 449,431 Liabilities: Foreign currency exchange contracts (b) $ — $ (327 ) $ — $ (327 ) Contingent acquisition payments (c) — — (2,550 ) (2,550 ) Total liabilities at fair value $ — $ (327 ) $ (2,550 ) $ (2,877 ) (a) Money market funds and time deposits with original maturity of 90 days or less are included within cash and cash equivalents in the consolidated balance sheets and are valued at quoted market prices in active markets. (b) Time deposits, commercial paper, corporate notes and bonds, and foreign currency exchange contracts are recorded at fair market values, which are determined based on the most recent observable inputs for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active or are directly or indirectly observable. Time deposits are generally for terms of one year or less. Commercial paper and corporate notes and bonds generally mature within three years and had a weighted average maturity of 0.31 years as of September 30, 2020 and 0.53 years as of September 30, 2019 . (c)
Changes in Fair Value of Level 3 Financial Instruments	e following table provides a summary of changes in fair value of our Level 3 financial instruments for the years ended September 30, 2020 and 2019 (dollars in thousands): Amount Balance as of September 30, 2018 $ 4,000 Earn-out liability established at time of acquisition 1,500 Payments and foreign currency translation (2,550 ) Adjustments to fair value included in acquisition-related costs, net (400 ) Balance as of September 30, 2019 2,550 Payments and foreign currency translation (4 ) Adjustments to fair value included in acquisition-related costs, net (750 ) Balance as of September 30, 2020 $ 1,796

Restructuring and Other Charg_2

Restructuring and Other Charges, Net (Tables)	12 Months Ended
	Sep. 30, 2020
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs [Table Text Block]	he components of restructuring and other charges, net are as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Personnel $ 5,305 $ 14,212 $ 27,360 Facilities 5,531 2,225 3,868 Total restructuring charges 10,836 16,437 31,228 Other charges 6,844 12,710 21,618 Total restructuring and other charges, net $ 17,680 $ 29,147 $ 52,846
Accrual Activity Relating to Restructuring and Other Charges	The following table represents the roll forward of restructuring liabilities for fiscal years 2020 , 2019 and 2018 (dollars in thousands): Personnel Facilities Total Balance at September 30, 2017 $ 1,509 $ 8,159 $ 9,668 Restructuring charges, net 27,360 3,868 31,228 Non-cash adjustment — (998 ) (998 ) Cash payments (20,534 ) (4,535 ) (25,069 ) Balance at September 30, 2018 8,335 6,494 14,829 Restructuring charges, net 14,212 2,225 16,437 Non-cash adjustment — (102 ) (102 ) Cash payments (18,960 ) (4,995 ) (23,955 ) Balance at September 30, 2019 3,587 3,622 7,209 ASC 842 implementation (a) — 11,674 11,674 Restructuring charges, net 5,305 5,531 10,836 Non-cash adjustment — 1,052 1,052 Cash payments (7,649 ) (6,266 ) (13,915 ) Balance at September 30, 2020 $ 1,243 $ 15,613 $ 16,856
Restructuring Charges by Segment	estructuring and other charges, net associated with each segment, but excluded from calculation of each segment's profit (dollars in thousands): Personnel Facilities Total Restructuring Other Charges Total Fiscal Year 2020 Healthcare $ 1,953 $ 2,819 $ 4,772 $ — $ 4,772 Enterprise 1,417 1,998 3,415 — 3,415 Other — (63 ) (63 ) — (63 ) Corporate 1,935 777 2,712 6,844 9,556 Total fiscal year 2020 $ 5,305 $ 5,531 $ 10,836 $ 6,844 $ 17,680 Fiscal Year 2019 Healthcare $ 4,679 $ 191 $ 4,870 $ — $ 4,870 Enterprise 5,037 933 5,970 — 5,970 Other 1,457 337 1,794 3,306 5,100 Corporate 3,039 764 3,803 9,404 13,207 Total fiscal year 2019 $ 14,212 $ 2,225 $ 16,437 $ 12,710 $ 29,147 Fiscal Year 2018 Healthcare $ 11,563 $ 25 $ 11,588 $ — $ 11,588 Enterprise 4,217 2,243 6,460 — 6,460 Other 1,473 647 2,120 7,103 9,223 Corporate 10,107 953 11,060 14,515 25,575 Total fiscal year 2018 $ 27,360 $ 3,868 $ 31,228 $ 21,618 $ 52,846

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Sep. 30, 2020
Supplemental Cash Flow Information [Abstract]
Cash Paid for Interest and Income Taxes	Cash paid for Interest and Income Taxes Year Ended September 30, 2020 2019 2018 (Dollars in thousands) Interest paid $ 50,346 $ 72,630 $ 93,121 Income taxes paid $ 30,918 $ 19,439 $ 13,758

earnings per share Schedules of

earnings per share Schedules of earnings per share (Tables)	12 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Year Ended September 30, 2020 2019 2018 (ASC 606) (ASC 606) (ASC 605) Numerator: Net income (loss) from continuing operations $ 28,782 $ (12,198 ) $ (236,837 ) Net (loss) income from discontinued operations (7,386 ) 226,008 76,909 Net income (loss) $ 21,396 $ 213,810 $ (159,928 ) Denominator: Weighted average common shares outstanding — Basic 282,644 286,347 291,318 Dilutive effect of convertible instruments 3,286 — — Dilutive effect of employee stock compensation plans (a) 6,064 — — Weighted average common shares outstanding — Diluted 291,994 286,347 291,318 Net income (loss) per common share - basic: Continuing operations $ 0.10 $ (0.04 ) $ (0.81 ) Discontinued operations (0.02 ) 0.79 0.26 Total net income (loss) per basic common share $ 0.08 $ 0.75 $ (0.55 ) Net income (loss) per common share - diluted: Continuing operations $ 0.10 $ (0.04 ) $ (0.81 ) Discontinued operations (0.03 ) 0.79 0.26 Total net income (loss) per diluted common share $ 0.07 $ 0.75 $ (0.55 ) Anti-dilutive equity instruments excluded from the calculation 453 1,047 528 Contingently issuable awards excluded from the calculation (a) 9 1,786 4,434

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Sep. 30, 2020
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Compensation expense is recorded ratably over the performance period of the award based on the estimated grant date fair value estimated at the grant date using a Monte Carlo simulation model, which included the following assumptions: Year ended September 30, 2020 2019 Dividend yield 0.0 % 0.0 % Expected volatility 27.73% - 28.24% 27.32% - 30.85% Risk-free interest rate 1.40% - 1.62% 2.23% - 3.02% Expected term (in years) 2.72 - 3 1 - 3
Stock Based Compensation Included in Consolidated Statements of Operations	Year Ended September 30, 2020 2019 2018 Cost of professional services and hosting $ 24,887 $ 26,647 $ 29,053 Cost of product and licensing 510 855 814 Cost of maintenance and support 1,663 1,314 3,322 Research and development 34,902 22,508 26,968 Sales and marketing 32,040 30,394 33,150 General and administrative 39,292 37,537 33,736 Total $ 133,294 $ 119,255 $ 127,043
Summary of Stock Options Activity	The table below summarizes activities related to stock options for the years ended September 30, 2020 , 2019 and 2018 : Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (a) Outstanding at September 30, 2017 23,807 $ 15.39 Exercised (2,963 ) $ 2.61 Expired (1,700 ) $ 15.99 Outstanding at September 30, 2018 19,144 $ 17.31 Exercised (3,314 ) $ 7.22 Expired (4,528 ) $ 17.89 Outstanding at September 30, 2019 11,302 $ 20.04 Exercised (3,830 ) $ 17.18 Equitable Adjustment - Cerence Spin-off (b) 1,883 Outstanding at September 30, 2020 9,355 $ 17.18 1.6 years $ 0.1 million Exercisable at September 30, 2020 9,355 $ 17.18 1.6 years $ 0.1 million Exercisable at September 30, 2019 11,302 Exercisable at September 30, 2018 19,144 (a)
Summary of Activity Relating to Restricted Units	RSUs and PSUs are not included in issued and outstanding common stock until the shares are vested and released. The table below summarizes activity relating to Restricted Units: Number of Shares Number of Shares Outstanding at September 30, 2017 5,043,931 6,477,164 Granted 2,175,537 8,876,712 Earned/released (2,092,862 ) (7,156,468 ) Forfeited (2,087,038 ) (1,325,321 ) Outstanding at September 30, 2018 3,039,568 6,872,087 Granted 1,342,836 9,500,077 Earned/released (1,405,485 ) (6,383,908 ) Modification (a) (296,759 ) 296,759 Forfeited (688,835 ) (1,286,071 ) Outstanding at September 30, 2019 1,991,325 8,998,944 Granted 1,067,900 6,401,949 Earned/released (303,198 ) (8,106,783 ) Forfeited (438,981 ) (1,452,467 ) Equitable Adjustment - Cerence Spin-off (b) 303,074 1,316,006 Outstanding at September 30, 2020 2,620,120 7,157,649 Weighted average remaining recognition period of outstanding Restricted Units 1.4 years 1.7 years Unrecognized stock-based compensation expense of outstanding Restricted Units $19.1 million $79.7 million Aggregate intrinsic value of outstanding Restricted Units (C) $87.0 million $237.6 million (a) 296,759 shares of performance-based awards were modified to time-based awards with only service conditions in December 2018. (b) Effective with the Distribution on October 1, 2019, outstanding equity awards were equitably adjusted by a conversion ratio of 1.16667 per one Nuance share then held. (c) The aggregate intrinsic value represents any excess of the closing price of our common stock as of September 30, 2020 ( $33.19
Summary of Weighted-Average Grant-Date Fair Value, Shares Issued and Total Stock-Based Compensation Expense Recognized Related to the Plan	A summary of the weighted-average grant-date fair value, shares issued, and total stock-based compensation expense recognized related to the ESPP are as follows: Year ended September 30, 2020 2019 2018 Weighted-average grant-date fair value per share $ 6.90 $ 3.76 $ 4.00 Total shares issued (in millions) 1.0 1.2 1.3 Total stock-based compensation expense (in millions) $ 4.2 $ 4.5 $ 5.2
Restricted Stock Units
Summary of Weighted-Average Grant-Date Fair Value and Intrinsic Value of Restricted Units Vested	(c) The aggregate intrinsic value represents any excess of the closing price of our common stock as of September 30, 2020 ( $33.19 ) over the exercise price of the underlying restricted units.
1995 Employee Stock Purchase Plan
Weighted Average Assumptions Used to Estimate Fair Value of Purchase Rights Granted	The fair value of the purchase rights granted under the ESPP was estimated on the date of grant using the Black-Scholes option-pricing model that uses the following weighted-average assumptions, which were derived in a manner similar to those discussed above relative to stock options: Year ended September 30, 2020 2019 2018 Dividend yield 0.0 % 0.0 % 0.0 % Expected volatility 39.8 % 27.8 % 32.1 % Risk-free interest rate 0.9 % 2.2 % 2.0 % Expected term (in years) 0.5 0.5 0.5

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Components of Income (Loss) Before Income Taxes	The components of income (loss) before income taxes are as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Domestic $ (21,170 ) $ (3,325 ) $ (230,955 ) Foreign 31,200 3,232 (83,042 ) Income (loss) before income taxes $ 10,030 $ (93 ) $ (313,997 )
Components of Benefit from Income Taxes	The components of the (benefit) provision for income taxes are as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Current: Federal $ 6,654 $ 5,023 $ (5,084 ) State 740 1,214 (2,007 ) Foreign 13,791 18,305 18,338 Total current 21,185 24,542 11,247 Deferred: Federal (17,969 ) 7,727 (84,569 ) State (13,216 ) 1,477 1,986 Foreign (8,752 ) (21,641 ) (5,824 ) Total deferred (39,937 ) (12,437 ) (88,407 ) (Benefit) provision for income taxes $ (18,752 ) $ 12,105 $ (77,160 ) Effective income tax rate (187.0 )% (13,016.1 )% 24.6 %
Reconciliation of Effective Tax Rate to Statutory Federal Rate	The (benefit) provision for income taxes differed from the amount computed by applying the federal statutory rate to our income tax before income taxes as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 Federal tax benefit at statutory rate $ 2,106 $ (20 ) $ (77,029 ) State tax (benefit) provision, net of federal benefit (9,740 ) 2,328 (508 ) Foreign tax rate and other foreign related tax items (4,047 ) 7,708 (4,275 ) Stock-based compensation (3,830 ) 3,368 3,290 Non-deductible expenditures 481 2,696 1,927 Executive compensation 6,445 1,662 503 Change in U.S. and foreign valuation allowance (28,709 ) 188,510 57,281 Capital losses 10,443 (179,635 ) — Intangible property transfers (14,800 ) (23,428 ) — Uncertain tax positions 18,020 4,428 4,415 Base erosion and anti-abuse tax 6,619 5,023 — TCJA impact — — (87,058 ) Goodwill impairment — — 28,640 Tax credits (11,206 ) (561 ) (4,499 ) Foreign dividend 12,806 1,026 736 Debt repurchases (3,442 ) — — Other 102 (1,000 ) (583 ) (Benefit) provision for income taxes $ (18,752 ) $ 12,105 $ (77,160 )
Deferred Tax Assets (Liabilities)	Deferred tax assets (liabilities) consist of the following as of September 30, 2020 and 2019 (dollars in thousands): September 30, 2020 September 30, 2019 Deferred tax assets: Net operating loss carryforwards $ 121,375 $ 166,224 Capital loss carryforwards 169,480 188,320 Federal and state credit carryforwards 44,181 43,897 Accrued expenses and other reserves 19,703 33,150 Difference in timing of revenue related items — 24,832 Deferred compensation 20,088 22,917 Lease liabilities 23,874 — Other 18,697 11,579 Total deferred tax assets 417,398 490,919 Valuation allowance for deferred tax assets (230,322 ) (303,378 ) Net deferred tax assets 187,076 187,541 Deferred tax liabilities: Depreciation (20,781 ) (16,833 ) Convertible debt (86,667 ) (87,046 ) Acquired intangibles (56,794 ) (7,517 ) Difference in timing of revenue related items (26,787 ) — Right-of-Use assets (18,345 ) — Net deferred tax (liabilities) assets $ (22,298 ) $ 76,145 Reported as: Other assets $ 47,818 $ 130,361 Long-term deferred tax liabilities (70,116 ) (54,216 ) Net deferred tax (liabilities) assets $ (22,298 ) $ 76,145
Aggregate Changes in Balance of Gross Unrecognized Tax Benefits	The aggregate changes in the balance of our gross unrecognized tax (benefits) provisions were as follows (dollars in thousands): Year Ended September 30, 2020 2019 Balance at the beginning of the year $ 24,111 $ 19,491 Increases related to tax positions from prior fiscal years 38,006 — Increases for tax positions taken during current period 6,866 5,517 Decreases for tax settlements and lapse in statutes (8,915 ) (860 ) Cumulative translation adjustments 413 (37 ) Balance at the end of the year $ 60,481 $ 24,111

Segment and Geographic Inform_2

Segment and Geographic Information and Significant Customers (Tables)	12 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Results Along with Reconciliation of Segment Profit to Income Before Income Taxes	The following table presents segment results along with a reconciliation of segment profits to income (loss) before income taxes (dollars in thousands): Year Ended September 30, 2020 2019 2018 Segment revenues: (ASC 606) (ASC 606) (ASC 605) Healthcare $ 915,332 $ 950,593 $ 984,819 Enterprise 529,978 510,753 483,194 Other 33,890 61,461 109,064 Total segment revenues 1,479,200 1,522,807 1,577,077 Acquisition related revenue adjustments (a) (301 ) (1,536 ) (9,477 ) Total consolidated revenue 1,478,899 1,521,271 1,567,600 Segment profit: Healthcare 298,751 333,526 322,715 Enterprise 146,923 131,169 130,173 Other 19,725 19,555 24,157 Total segment profit 465,399 484,250 477,045 Corporate expenses and other, net (119,945 ) (137,558 ) (183,657 ) Acquisition-related revenues and costs of revenues adjustment (301 ) (1,536 ) (9,477 ) Stock-based compensation (133,294 ) (119,255 ) (127,043 ) Amortization of intangible assets (78,707 ) (81,622 ) (105,375 ) Acquisition-related costs, net (2,884 ) (7,965 ) (12,010 ) Restructuring and other charges, net (17,680 ) (29,147 ) (52,846 ) Impairment of goodwill and other intangible assets — — (170,941 ) Other expenses, net (102,558 ) (107,260 ) (129,693 ) Income (loss) before income taxes $ 10,030 $ (93 ) $ (313,997 ) (a) Segment revenues differ from reported revenues due to certain revenue adjustments related to acquisitions that would otherwise have been recognized but for the purchase accounting treatment of the business combinations. These revenues are included to allow for more complete comparisons to the financial results of historical operations and in evaluating management performance.
Classification of Revenue By Major Geographic Areas	Revenue, classified by the major geographic areas in which our customers are located, was as follows (dollars in thousands): Year Ended September 30, 2020 2019 2018 (ASC 606) (ASC 606) (ASC 605) United States $ 1,185,760 $ 1,237,406 $ 1,255,203 International 293,139 283,865 312,397 Total $ 1,478,899 $ 1,521,271 $ 1,567,600
Location of Long-Lived Assets Including Intangible Assets and Goodwill	Our long-lived assets from continuing operations, including intangible assets and goodwill, were located as follows (dollars in thousands): September 30, September 30, United States $ 2,254,424 $ 2,086,932 International 602,923 787,040 Total $ 2,857,347 $ 2,873,972

Quarterly Data (Unaudited) (Tab

Quarterly Data (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Data Derived from Unaudited Consolidated Financial Statements with All Recurring Adjustments	The following information has been derived from unaudited consolidated financial statements that, in the opinion of management, include all recurring adjustments necessary for a fair statement of such information (dollars in thousands, except per share amounts): First Quarter Second Quarter (a) Third Quarter Fourth Quarter Fiscal Year 2020 Total revenue $ 418,233 $ 369,337 $ 338,398 $ 352,931 $ 1,478,899 Gross profit $ 233,844 $ 212,244 $ 194,216 $ 199,656 $ 839,960 Net income (loss) from continuing operations $ 54,877 $ (20,006 ) $ 16,662 $ (22,751 ) $ 28,782 Net income (loss) per share - continuing operations: Basic $ 0.19 $ (0.07 ) $ 0.06 $ (0.08 ) $ 0.10 Diluted $ 0.19 $ (0.07 ) $ 0.06 $ (0.08 ) $ 0.10 Weighted average common shares outstanding: Basic 284,130 282,576 281,281 282,556 282,644 Diluted 289,453 282,576 287,852 282,556 291,994 First Quarter Second Quarter Third Quarter Fourth Quarter Fiscal Year 2019 Total revenue $ 419,675 $ 336,584 $ 377,437 $ 387,575 $ 1,521,271 Gross profit $ 235,555 $ 177,325 $ 205,667 $ 219,240 $ 837,787 Net income (loss) from continuing operations $ 13,881 $ (28,397 ) $ (687 ) $ 3,005 $ (12,198 ) Net income (loss) per share - continuing operations: Basic $ 0.05 $ (0.10 ) $ — $ 0.01 $ (0.04 ) Diluted $ 0.05 $ (0.10 ) $ — $ 0.01 $ (0.04 ) Weighted average common shares outstanding: Basic 287,796 285,866 285,942 285,754 286,347 Diluted 292,359 285,866 285,942 291,598 286,347 (a) On March 27, 2020, the CARES Act was enacted, which provided a technical correction to a provision in the TCJA related to the characterization of federal net operating losses ("NOLs") generated during fiscal year 2018. Under the TCJA, NOLs generated in fiscal years that straddled December 31, 2017 were designated as indefinite-lived NOLs. The CARES Act amended this legislation to designate these NOLs as definite-lived NOLs. This recharacterization resulted in an increase of $6.5 million in deferred tax assets related to our definite lived NOLs, thus requiring additional valuation allowance of the same amount. This adjustment was identified during the fiscal third quarter ending June 30, 2020. We determined that these amounts are not material to our previously issued condensed consolidated financial statements for the three months ended March 31, 2020. The amounts for the second quarter of fiscal year 2020 above have been adjusted to reflect this adjustment.

Operating Leases (Tables)

Operating Leases (Tables)	12 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future lease payments under operating leases as of September 30, 2020 were as follows (dollars in thousands): Fiscal Year Operating Leases Operating leases under restructuring Total 2021 $ 27,944 $ 4,492 $ 32,436 2022 23,162 3,805 26,967 2023 16,766 3,440 20,206 2024 14,496 1,996 16,492 2025 12,547 1,346 13,893 Thereafter 41,046 1,843 42,889 Total $ 135,961 $ 16,922 $ 152,883

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Narrative (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Significant Accounting Policies [Line Items]
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle		$ 233,415	$ (882)
Capitalized Computer Software, Net	$ 55,600	26,300
Advertising costs incurred	16,100	16,900	16,500
Total comprehensive income (loss), net of taxes	36,251	203,900	(181,449)
Foreign currency transaction gains (losses)	$ 1,300	$ 1,100	$ (1,200)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	453	1,047	528
Sales and marketing	$ 273,324	$ 274,031	$ 286,550

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Receivable Allowances (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	$ 9,797	$ 8,869	$ 11,106
Valuation Allowances and Reserves, Bad debt provision	2,117	2,375	2,011
Valuation Allowances and Reserves, Write-offs, net of recoveries	(799)	(1,447)	(4,248)
Valuation Allowances and Reserves, Adjustments	0	0	0
Valuation Allowances and Reserves, Ending Balance	11,115	9,797	8,869
SEC Schedule, 12-09, Allowance, Sales Returns [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	4,591	6,145	29,541
Valuation Allowances and Reserves, Bad debt provision	0	0	0
Valuation Allowances and Reserves, Write-offs, net of recoveries	0	0	0
Valuation Allowances and Reserves, Adjustments	(935)	(1,554)	(23,396)
Valuation Allowances and Reserves, Ending Balance	$ 3,656	$ 4,591	$ 6,145

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Acquisition-Related Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Accounting Policies [Abstract]
Business Combination, Integration Related Costs	$ 3,778	$ 7,568	$ 14,443
Professional service fees	(23)	1,940	983
Business Combination Acquisition Related Adjustments	871	(1,543)	(3,416)
Acquisition-related costs, net	$ 2,884	$ 7,965	$ 12,010

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Accounting Policies [Abstract]
Foreign currency translation adjustment	$ (110,110)	$ (124,608)
Net unrealized losses on post-retirement benefits	(7,873)	(8,296)
Net unrealized losses on post-retirement benefits	65	131
Total	$ (117,918)	$ (132,773)

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Net Income (Loss) Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Basic
Net income (loss)	$ (22,751)	$ 16,662	$ (20,006)	$ 54,877	$ 3,005	$ (687)	$ (28,397)	$ 13,881	$ 21,396	$ 213,810	$ (159,928)
Diluted
Net income (loss) attributable to common stockholders - diluted	$ (22,751)	$ 16,662	$ (20,006)	$ 54,877	$ 3,005	$ (687)	$ (28,397)	$ 13,881	$ 21,396	$ 213,810	$ (159,928)
Basic
Basic (in shares)	282,556	281,281	282,576	284,130	285,754	285,942	285,866	287,796	282,644	286,347	291,318

Summary of Significant Accoun_8

Summary of Significant Accounting Policies Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019	Feb. 01, 2019
Significant Accounting Policies [Line Items]
Operating lease, Right-of-use Asset	$ 110,276	$ 0	$ 120,000
Operating Lease, Liability		140,000
Deferred Rent Asset, Net, Current		$ 20,000

Summary of Significant Accoun_9

Summary of Significant Accounting Policies recent accounting pronouncement (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
SEC Schedule, 12-09, Allowance, Sales Returns [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ 3,656	$ 4,591	$ 6,145	$ 29,541

Revenue Recognition Disaggregat

Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2017	Sep. 30, 2020		Sep. 30, 2019		Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Hardware revenue									$ 28,000		$ 30,000
Capitalized Contract Cost, Net, Current	$ 22,500				$ 19,900				22,500		19,900
Professional services and hosting									926,044		913,643
Product and licensing									296,127		338,693		$ 375,230
Maintenance and support									256,728		268,935		252,326
Total revenues	352,931	$ 338,398	$ 369,337	$ 418,233	387,575	$ 377,437	$ 336,584	$ 419,675	1,478,899	[1]	1,521,271	[1]	$ 1,567,600	[1]
Capitalized Contract Cost, Net, Noncurrent	$ 54,100				$ 30,100				54,100		30,100
Healthcare
Disaggregation of Revenue [Line Items]
Professional services and hosting									577,787		546,037
Product and licensing									201,207		246,788
Maintenance and support									136,338		156,905
Total revenues									915,332		949,730
Enterprise
Disaggregation of Revenue [Line Items]
Professional services and hosting									319,347		316,247
Product and licensing									89,950		82,073
Maintenance and support									120,380		111,758
Total revenues									529,677		510,078
Other Mobile Businesses [Member]
Disaggregation of Revenue [Line Items]
Professional services and hosting									28,910		51,359
Product and licensing									4,970		9,832
Maintenance and support									10		272
Total revenues									$ 33,890		$ 61,463
[1]	Segment revenues differ from reported revenues due to certain revenue adjustments related to acquisitions that would otherwise have been recognized but for the purchase accounting treatment of the business combinations. These revenues are included to allow for more complete comparisons to the financial results of historical operations and in evaluating management performance.

Revenue Recognition Revenue f_2

Revenue Recognition Revenue from Contract with Customers (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Revenue Recognition [Abstract]
Hardware revenue	$ 28	$ 30
Capitalized Contract Cost, Net, Current	22.5	19.9
Capitalized Contract Cost, Net, Noncurrent	54.1	30.1
Capitalized Contract Cost, Amortization	18.5	15.5
Deferred Costs, Current	18.5	17.2
Deferred Costs, Noncurrent	32.8	38.5
Contract with Customer, Asset, after Allowance for Credit Loss, Current	49.3	58.7
Contract with Customer, Asset, after Allowance for Credit Loss, Noncurrent	$ 109.9	$ 108.7

Revenue Recognition Contract _2

Revenue Recognition Contract Assets (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2020USD ($)
Contract Assets [Abstract]
Balance September 30, 2019	$ 167,324
Revenues recognized but not billed	286,242
Amounts reclassified to accounts receivable	294,315
Balance September 30, 2020	$ 159,251

Revenue Recognition Contract _3

Revenue Recognition Contract liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Contract Liability [Abstract]
Balance September 30, 2019	$ 365,632	$ 348,006
Amounts bill but not recognized	819,049
Revenue recognized	$ 801,423

Revenue Recognition Revenue, _2

Revenue Recognition Revenue, Remaining Performance Obligation (Details) $ in Millions	Sep. 30, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 1,734,438
Within One Year [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	708,343
Two to Five Years [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	963,223
Greater than Five Years [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 62,872

Disposition of Business (Detail

Disposition of Business (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash Provided by (Used in) Operating Activities, Discontinued Operations	$ (13,307)	$ 96,771	$ 203,447
Deferred Tax Asset, Parent's Basis in Discontinued Operation		73,800
Document Period End Date	Sep. 30, 2020
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net		67,928
Gain (Loss) on Disposition of Business	$ 0	102,371	0
Disposal Group, Including Discontinued Operation, Revenue	0	369,251	484,061
Provision for Income Taxes, Discontinued Operations	0	(103,387)	20,353
Disposal Group, Including Discontinued Operation, Costs of Goods Sold	0	113,381	130,168
Other	(13,117)	(870)	(1,767)
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	(7,386)	20,250	97,262
Net (loss) income from discontinued operations	(7,386)	226,008	76,909
Depreciation, Discontinued Operations	0	8,204	10,928
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	28,510	42,591
Stock Compensation Expense, Discontinued Operations	0	29,060	23,742
Disposal Group, Including Discontinued Operation, Assets		1,328,466
Disposal Group, Including Discontinued Operation, Accounts Payable		14,039
Disposal Group, Including Discontinued Operation, Accrued Liabilities		27,429
Disposal Group, Including Discontinued Operation, Deferred Revenue		353,700
Disposal Group, Including Discontinued Operation, Other Liabilities		21,603
Disposal Group, Including Discontinued Operation, Liabilities		416,771
Disposal Group, Capital Expenditures	0	5,977	9,331
Other Payments to Acquire Businesses	0	0	79,802
Disposal Group, Including Discontinued Operation, Prepaid and Other Assets		23,930
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment		20,113
Disposal Group, Including Discontinued Operation, Goodwill		1,115,568
Disposal Group, Including Discontinued Operation, Intangible Assets		65,561
Disposal Group, Including Discontinued Operation, Other Assets		35,366
Other Expense [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Operating Expense	0	17,743	25,936
Acquisition-related Costs [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Operating Expense	0	558	4,091
General and administrative
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Operating Expense	0	4,367	15,965
Selling and Marketing Expense
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Operating Expense	0	57,905	101,755
Research and development
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Operating Expense	0	90,810	98,134
Restructuring Charges [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Operating Expense	7,386	64,569	10,652
Other Operating Income	$ 0	$ 332	$ 98

Business Acquisitions - Additio

Business Acquisitions - Additional Information (Details)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Number of Years in Measurement Period from Acquisition Date to Change Underlying Assumptions	5 years	5 years 9 months 18 days

Business Acquisitions Business

Business Acquisitions Business Acquisitions - Current Year (Details) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2020
Business Acquisition [Line Items]
Share Price			$ 33.19
Number of Years in Measurement Period from Acquisition Date to Change Underlying Assumptions	5 years	5 years 9 months 18 days
Other Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 19,700,000	$ 28,500,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	8,800,000	15,700,000
Identifiable Intangible Assets Acquired	10,500,000	11,200,000
Cash and Cash Equivalents [Member] | Other Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	17,800,000	26,500,000
Contingent Consideration Payments [Member] | Other Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 1,500,000	$ 2,000,000

Business Acquisitions Busines_2

Business Acquisitions Business Acquisitions - Prior Year (Details) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2020
Business Acquisition [Line Items]
Contingent and deferred acquisition payments	$ 17,470,000		$ 4,224,000
Number of Years in Measurement Period from Acquisition Date to Change Underlying Assumptions	5 years	5 years 9 months 18 days
Other Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 19,700,000	$ 28,500,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	8,800,000	15,700,000
Identifiable Intangible Assets Acquired	10,500,000	11,200,000
Cash and Cash Equivalents [Member] | Other Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	17,800,000	26,500,000
Contingent Consideration Payments [Member] | Other Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	1,500,000	$ 2,000,000
Warrant [Member] | Other Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 300,000

Business Acquisitions Busines_3

Business Acquisitions Business Acquisition - Prior Year (2 yrs) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Other Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 19.7	$ 28.5

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2020	Sep. 30, 2019
Goodwill
Beginning balance			$ 2,127,896	$ 2,127,159
Goodwill acquired				8,785
Goodwill, Purchase Accounting Adjustments			(31)	113
Effect of foreign currency translation			5,847	(8,161)
Ending balance	$ 2,127,159		2,133,712	2,127,896
Mobile Reporting Unit [Member]
Goodwill
Ending balance		$ 36,000
Goodwill, Impairment Loss	(400)	(35,100)
Healthcare
Goodwill
Beginning balance			1,435,144	1,430,325
Goodwill acquired				8,785
Goodwill, Purchase Accounting Adjustments			(31)	113
Effect of foreign currency translation			3,063	(4,079)
Ending balance	1,430,325		1,438,176	1,435,144
Automotive
Goodwill
Ending balance		$ 1,080,500
Enterprise
Goodwill
Beginning balance			679,903	683,347
Goodwill acquired				0
Goodwill, Purchase Accounting Adjustments			0	0
Effect of foreign currency translation			2,697	(3,444)
Ending balance	683,347		682,600	679,903
Other Segments [Member]
Goodwill
Beginning balance			12,849	13,487
Goodwill acquired				0
Goodwill, Purchase Accounting Adjustments			0	0
Effect of foreign currency translation			87	(638)
Ending balance	$ 13,487		$ 12,936	$ 12,849

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 757,462	$ 677,308
Accumulated Amortization	(543,978)	(385,937)
Net Carrying Amount	213,484	291,371
Net Carrying Amount (excluding goodwill)	213,484	291,371
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	523,042	500,953
Accumulated Amortization	(360,617)	(292,127)
Net Carrying Amount	$ 162,425	$ 208,826
Weighted Average Remaining Life (Years)	4 years 4 months 24 days	5 years 3 months 18 days
Technology and patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 205,451	$ 147,394
Accumulated Amortization	(154,926)	(69,259)
Net Carrying Amount	$ 50,525	$ 78,135
Weighted Average Remaining Life (Years)	3 years 1 month 6 days	3 years 9 months 18 days
Trade names, trademarks and other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 28,969	$ 28,961
Accumulated Amortization	(28,435)	(24,551)
Net Carrying Amount	$ 534	$ 4,410
Weighted Average Remaining Life (Years)	10 months 24 days	1 year 2 months 12 days

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Line Items]
Cost, Depreciation and Amortization			$ 27,800	$ 27,400	$ 40,200
Document Fiscal Year Focus			2020
Other Asset Impairment Charges			$ 0	0	10,550
Goodwill	$ 2,127,159		2,133,712	2,127,896	2,127,159
Intangible assets			213,484	291,371
Impairment of goodwill and other intangible assets			0	0	170,941
Intangible Assets Amortization Expense			50,897	54,206	$ 65,157
Technology and patents
Goodwill And Intangible Assets Disclosure [Line Items]
Intangible assets			50,525	78,135
Trade names, trademarks and other
Goodwill And Intangible Assets Disclosure [Line Items]
Intangible assets			534	4,410
Customer Relationships
Goodwill And Intangible Assets Disclosure [Line Items]
Intangible assets			$ 162,425	$ 208,826
SRS [Member]
Goodwill And Intangible Assets Disclosure [Line Items]
Other Asset Impairment Charges	900
Goodwill, Impairment Loss	3,400
Impairment of goodwill and other intangible assets	25,100
SRS [Member] | Technology and patents
Goodwill And Intangible Assets Disclosure [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)	7,900
SRS [Member] | Customer Relationships
Goodwill And Intangible Assets Disclosure [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)	12,900
Mobile Reporting Unit [Member]
Goodwill And Intangible Assets Disclosure [Line Items]
Other Asset Impairment Charges	6,200
Goodwill		$ 36,000
Goodwill, Impairment Loss	400	35,100
Impairment of goodwill and other intangible assets	15,000	102,800
Mobile Reporting Unit [Member] | Technology and patents
Goodwill And Intangible Assets Disclosure [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)	800
Mobile Reporting Unit [Member] | Customer Relationships
Goodwill And Intangible Assets Disclosure [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)	$ 7,600
Dragon TV [Member]
Goodwill And Intangible Assets Disclosure [Line Items]
Goodwill		$ 12,000

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets Goodwill and Intangible Assets - Estimated Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Cost, Depreciation and Amortization	$ 27,800	$ 27,400	$ 40,200
Intangible Assets Amortization Expense	50,897	54,206	$ 65,157
2015	60,030
2016	56,060
2017	46,003
2018	25,010
2019	19,032
Thereafter	7,349
Total	213,484	$ 291,371
Cost of Revenue
Finite-Lived Intangible Assets [Line Items]
2015	16,994
2016	16,272
2017	12,323
2018	4,936
2019	0
Thereafter	0
Total	50,525
Operating Expense [Member]
Finite-Lived Intangible Assets [Line Items]
2015	43,036
2016	39,788
2017	33,680
2018	20,074
2019	19,032
Thereafter	7,349
Total	$ 162,959

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Receivables [Abstract]
Trade accounts receivable	$ 215,347	$ 255,061
Less - allowance for doubtful accounts	(11,115)	(9,797)
Less - allowance for sales returns	(3,656)	(4,591)
Accounts receivable, net	$ 200,576	$ 240,673

Land, Building and Equipment,_3

Land, Building and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Property, Plant and Equipment [Line Items]
Land, building and equipment, gross	$ 408,494	$ 361,196
Less: accumulated depreciation	(265,066)	(239,993)
Land, building and equipment, net	143,428	121,203
Land [Member]
Property, Plant and Equipment [Line Items]
Land, building and equipment, gross	$ 2,400	2,400
Building
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	30 years
Land, building and equipment, gross	$ 6,741	6,696
Building | Minimum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	0 years
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Land, building and equipment, gross	$ 156,454	159,681
Machinery and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	3 years
Machinery and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	5 years
Computers, Software and Equipment
Property, Plant and Equipment [Line Items]
Land, building and equipment, gross	$ 157,000	131,012
Computers, Software and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	3 years
Computers, Software and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	5 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Land, building and equipment, gross	$ 32,988	26,244
Leasehold Improvements | Minimum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	2 years
Leasehold Improvements | Maximum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	15 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Land, building and equipment, gross	$ 11,217	14,455
Furniture and Fixtures | Minimum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	5 years
Furniture and Fixtures | Maximum
Property, Plant and Equipment [Line Items]
Building and equipment useful life (in years)	7 years
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Land, building and equipment, gross	$ 41,694	$ 20,708

Land, Building and Equipment,_4

Land, Building and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment	$ (37,772)	$ (47,417)	$ (51,426)
Software Development [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment	$ (5,200)	$ (4,100)	$ (7,000)

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Accrued Liabilities, Current [Abstract]
Compensation	$ 117,963	$ 119,412
Accrued interest payable	13,484	19,302
Cost of revenue related liabilities	29,953	58,012
Consulting and professional fees	10,857	20,401
Facilities related liabilities	0	2,503
Sales and marketing incentives	2,021	2,692
Sales and other taxes payable	6,339	8,089
Operating Lease, Liability, Current	28,273	0
Other	4,374	19,159
Total	$ 213,264	$ 249,570

Deferred Revenue Deferred Reven

Deferred Revenue Deferred Revenue (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Deferred Revenue Arrangement [Line Items]
Deferred Revenue, Current	$ 261,323	$ 214,223
Deferred Revenue, Noncurrent	$ 104,309	$ 133,783

Credit Facilities and Debt - Sc

Credit Facilities and Debt - Schedule of Borrowing Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019	Nov. 01, 2017	Jun. 21, 2016	Dec. 07, 2015	Jun. 01, 2015	Oct. 24, 2011
Debt Instrument [Line Items]
Long-Term Debt, Maturity, Year One	$ 490,051
Long-Term Debt, Maturity, Year Two	0
Long-Term Debt, Maturity, Year Three	676,488
Long-Term Debt, Maturity, Year Four	0
Long-Term Debt, Maturity, Year Five	0
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	500,000
Long-term Debt, Gross	1,666,539
Debt Instrument, Unamortized Discount (Premium), Net	(129,866)
Debt Issuance Costs, Noncurrent, Net	(451)	$ (511)
Long-term Debt	1,536,673	1,936,406
Less: current portion	(432,209)	(1,142,870)
Long-term Debt, Fair Value	2,355,500	2,143,400
Long-term debt, face value	1,666,500	2,137,000
Long-term portion of debt	1,104,464	793,536
Convertible Debt [Member]
Debt Instrument [Line Items]
Long-Term Debt, Maturity, Year One	490,051
Long-Term Debt, Maturity, Year Two	0
Long-Term Debt, Maturity, Year Three	676,488
Long-Term Debt, Maturity, Year Four	0
Long-Term Debt, Maturity, Year Five	0
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	0
Long-term Debt, Gross	1,166,539
Debt Instrument, Unamortized Discount (Premium), Net	(125,563)
Long-term Debt	1,040,976
Senior Notes [Member]
Debt Instrument [Line Items]
Long-Term Debt, Maturity, Year One	0
Long-Term Debt, Maturity, Year Two	0
Long-Term Debt, Maturity, Year Three	0
Long-Term Debt, Maturity, Year Four	0
Long-Term Debt, Maturity, Year Five	0
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	500,000
Long-term Debt, Gross	500,000
Debt Instrument, Unamortized Discount (Premium), Net	(4,303)
Long-term Debt	495,697
2.75% Convertible Debentures due November 1, 2031
Debt Instrument [Line Items]
2.75% Convertible Debentures, net of unamortized discount	0	46,568
Long-term debt, face value			$ 46,600		$ 395,500		$ 690,000
Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
2.75% Convertible Debentures, net of unamortized discount	216,627	240,406
Long-term debt, face value						$ 263,900
6.0% Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
5.375% Senior Notes due 2020	0	298,529		$ 300,000
Long-term debt, face value				$ 300,000
Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
5.375% Senior Notes due 2020	$ 608,767	$ 580,639
Long-term debt, face value					$ 676,500

Credit Facilities and Debt - Bo

Credit Facilities and Debt - Borrowing Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Mar. 13, 2017	Dec. 22, 2016	Jun. 21, 2016	Dec. 07, 2015	Dec. 31, 2014	Oct. 24, 2011
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ 18,656	$ 910	$ (348)
Debt Issuance Costs, Noncurrent, Net	451	511
5.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
5.375% Senior Notes due 2020	$ 496,148	$ 495,518			$ 500,000
Convertible debentures, interest rate	5.625%	5.625%			5.625%
Debt Instrument, Unamortized Premium	$ 0	$ 0
Unamortized Debt Issuance Expense	$ 4,500	$ 5,100
Debt Instrument, Interest Rate, Effective Percentage	5.625%	5.625%
nuan_DebtInstrumentMaturityYear	2026	2026
6.0% Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
5.375% Senior Notes due 2020	$ 0	$ 298,529				$ 300,000
Convertible debentures, interest rate	6.00%	6.00%				6.00%
Debt Instrument, Unamortized Premium	$ 0	$ 0				$ (13,500)
Unamortized Debt Issuance Expense	$ 1,500	$ 1,800
Debt Instrument, Interest Rate, Effective Percentage	6.00%	6.00%
nuan_DebtInstrumentMaturityYear	2024	2024
5.375% Senior Notes due August 15, 2020
Debt Instrument [Line Items]
Convertible debentures, interest rate	5.375%	5.375%			5.375%
Debt Instrument, Unamortized Premium	$ 0	$ 0
Unamortized Debt Issuance Expense	$ 0	$ 1,200
Debt Instrument, Interest Rate, Effective Percentage	5.375%	5.375%
nuan_DebtInstrumentMaturityYear	2020	2020
2.75% Convertible Debentures due November 1, 2031
Debt Instrument [Line Items]
Convertible debentures, interest rate	2.75%	2.75%						2.75%	2.75%
Unamortized Debt Issuance Expense	$ 0	$ 0
Debt Instrument, Interest Rate, Effective Percentage	7.432%	7.432%
nuan_DebtInstrumentMaturityYear	2031	2031
Debt Instrument, Unamortized Discount	$ 0	$ 0
2.75% Convertible Debentures, net of unamortized discount	0	46,568
1.25% Convertible Debentures due 2025 [Member]
Debt Instrument [Line Items]
2.75% Convertible Debentures, net of unamortized discount	$ 215,582	$ 275,257
Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Convertible debentures, interest rate	1.50%	1.50%
Unamortized Debt Issuance Expense	$ 800	$ 1,100
Debt Instrument, Interest Rate, Effective Percentage	5.394%	5.394%
nuan_DebtInstrumentMaturityYear	2035	2035
Debt Instrument, Unamortized Discount	$ 22,700	$ 32,800
2.75% Convertible Debentures, net of unamortized discount	216,627	240,406
Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
5.375% Senior Notes due 2020	$ 608,767	$ 580,639
Convertible debentures, interest rate	1.00%	1.00%					1.00%
Unamortized Debt Issuance Expense	$ 4,300	$ 5,600
Debt Instrument, Interest Rate, Effective Percentage	5.622%	5.622%
nuan_DebtInstrumentMaturityYear	2035	2035
Debt Instrument, Unamortized Discount	$ 91,600	$ 116,900
Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
Convertible debentures, interest rate	1.25%	1.25%		1.25%
Unamortized Debt Issuance Expense	$ 3,100	$ 3,700
Debt Instrument, Interest Rate, Effective Percentage	5.578%	5.578%
nuan_DebtInstrumentMaturityYear	2025	2025
Debt Instrument, Unamortized Discount	$ 71,600	$ 82,400
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount	$ 0	$ 0

Credit Facilities and Debt - 5.

Credit Facilities and Debt - 5.375% Senior Notes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Dec. 22, 2016
Line of Credit Facility [Line Items]
Gain (Loss) on Extinguishment of Debt	$ (18,656)	$ (910)	$ 348
Long-term debt, face value	$ 1,666,500	$ 2,137,000
5.375% Senior Notes due August 15, 2020
Line of Credit Facility [Line Items]
Senior notes, stated interest rate	5.375%	5.375%		5.375%
Unamortized Debt Issuance Expense	$ 0	$ 1,200

Credit Facilities and Debt - 2.

Credit Facilities and Debt - 2.75% Convertible Notes due 2031 (Details) - USD ($)	1 Months Ended	3 Months Ended			12 Months Ended
	Mar. 31, 2020	Dec. 31, 2017	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Nov. 01, 2017	Dec. 07, 2015	Jun. 01, 2015	Oct. 24, 2011
Debt Instrument [Line Items]
Long-term debt, face value					$ 1,666,500,000	$ 2,137,000,000
Loss on extinguishment of debt					18,656,000	910,000	$ (348,000)
Debt Issuance Costs, Noncurrent, Net					451,000	511,000
2.75% Convertible Debentures due November 1, 2031
Debt Instrument [Line Items]
Long-term debt, face value								$ 46,600,000	$ 395,500,000		$ 690,000,000
Repayments of Debt	$ 46,600,000
Repayments of Convertible Debt		$ 331,200,000	$ 256,200,000	$ 38,300,000	$ 17,800,000	38,300,000
Principal Amount Per Note Used In Conversion Rate						$ 1,000
Convertible debentures, interest rate				2.75%	2.75%	2.75%					2.75%
debt instrument net proceeds											$ 676,100,000
Convertible Debt, Noncurrent											533,600,000
Debt Instrument, Convertible, Carrying Amount of Equity Component											$ 156,400,000
Debt Instrument, Unamortized Discount					$ 0	$ 0
Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Long-term debt, face value									$ 676,500,000
Debt Instrument, Convertible, Conversion Price									$ 24.12
Convertible debentures, interest rate					1.00%	1.00%			1.00%
Convertible Debt, Noncurrent									$ 495,400,000
Debt Instrument, Convertible, Carrying Amount of Equity Component									$ 181,100,000
Debt Instrument, Unamortized Discount					$ (91,600,000)	$ (116,900,000)
Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Long-term debt, face value										$ 263,900,000
Aggregate Principal Amount of Senior Notes, Redemption Price, Percentage					100.00%
Debt Instrument, Convertible, Conversion Price										$ 20.61
Convertible debentures, interest rate					1.50%	1.50%
debt instrument net proceeds										$ 253,200,000
Convertible Debt, Noncurrent										208,600,000
Debt Instrument, Convertible, Carrying Amount of Equity Component										$ 55,300,000
Debt Instrument, Unamortized Discount					$ (22,700,000)	$ (32,800,000)
Minimum | Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage									130.00%
Debt Instrument Conversion Circumstance Number Of Trading Days						20 days
Minimum | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage						130.00%
Debt Instrument Conversion Circumstance Number Of Trading Days					20 days
Maximum | Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage									98.00%
Debt Instrument Conversion Circumstance Number Of Trading Days						30 days
Principal Amount Per Note Used In Conversion Rate									$ 1,000
Maximum | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage						98.00%
Ending on Last Trading Day of Previous Fiscal Quarter [Member] | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument Conversion Circumstance Number Of Consecutive Trading Days					30 days

Credit Facilities and Debt Cred

Credit Facilities and Debt Credit Facilities and Debt - 2.75% Convertible Debentures due 2027 (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Long-term debt, face value	$ 1,666,500	$ 2,137,000
Debt Issuance Costs, Noncurrent, Net	$ 451	$ 511

Credit Facilities and Debt Cr_2

Credit Facilities and Debt Credit Facilities and Debt - Credit Facilities Narrative (Details)	12 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Mar. 24, 2020USD ($)
Line of Credit Facility [Line Items]
Loss on extinguishment of debt	$ 18,656,000	$ 910,000	$ (348,000)
Long-term debt, face value	1,666,500,000	$ 2,137,000,000
Pledged Financial Instruments, Not Separately Reported, Securities for Letter of Credit Facilities	25,000,000
Other Borrowings				$ 230,000,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 242,500,000
Banking Regulation, Supplementary Leverage Ratio, Undercapitalized, Minimum	4
Letters of Credit Outstanding, Amount	$ 2,400,000
Line of Credit Facility, Remaining Borrowing Capacity	$ 240,100,000
Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member]
Line of Credit Facility [Line Items]
Convertible debentures, interest rate	2.68%
Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member] | Minimum | London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member] | Minimum | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member] | Maximum | London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.75%
Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member] | Maximum | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.75%

Credit Facilities and Debt Cr_3

Credit Facilities and Debt Credit Facilities and Debt - Credit Facilities Margin for Borrowings Table (Details) - Revolving Credit Facility Due March Thirty One Twenty Fifteen [Member]	12 Months Ended
	Sep. 30, 2020
Maximum | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.75%
Maximum | London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.75%
Minimum | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Minimum | London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%

Credit Facilities and Debt Cr_4

Credit Facilities and Debt Credit Facilities and Debt - Credit Facilities Annual Aggregate Principal Table (Details) $ in Thousands	Sep. 30, 2020USD ($)
Debt Instrument [Line Items]
Long-Term Debt, Maturity, Year One	$ 490,051
Long-Term Debt, Maturity, Year Two	0
Long-Term Debt, Maturity, Year Three	676,488
Long-Term Debt, Maturity, Year Four	$ 0

Credit Facilities and Debt Cr_5

Credit Facilities and Debt Credit Facilities and Debt - 5.375% Senior Notes due 2020 (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Dec. 22, 2016
Debt Instrument [Line Items]
Gain (Loss) on Extinguishment of Debt	$ (18,656)	$ (910)	$ 348
Long-term Debt	$ 1,536,673	$ 1,936,406
5.375% Senior Notes due August 15, 2020
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	5.375%	5.375%
Unamortized Debt Issuance Expense	$ 0	$ 1,200
Senior notes, stated interest rate	5.375%	5.375%		5.375%
Term Loan Facility Due August Seventh Twenty Ninteen [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 472,500

Credit Facilities and Debt 1.50

Credit Facilities and Debt 1.50% Convertible Debentures due 2035 (Details) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 31, 2017	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Mar. 31, 2020	Nov. 01, 2017	Dec. 07, 2015	Jun. 01, 2015	Oct. 24, 2011
Debt Instrument [Line Items]
Long-term debt, face value				$ 1,666,500,000	$ 2,137,000,000
Debt Issuance Costs, Noncurrent, Net				$ 451,000	$ 511,000
Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Long-term debt, face value									$ 676,500,000
Convertible debentures, interest rate				1.00%	1.00%				1.00%
Proceeds from long-term debt, net of issuance costs					$ 663,800,000
Convertible Debt, Noncurrent									$ 495,400,000
Debt Instrument, Convertible, Carrying Amount of Equity Component									$ 181,100,000
Debt Instrument, Unamortized Discount				$ 91,600,000	$ 116,900,000
Debt Instrument, Convertible, Conversion Price									$ 24.12
Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Unamortized Loss Reacquired Debt, Noncurrent							$ 2,500,000
Debt Instrument, Repurchase Amount							41,300,000
debt issuance cost write off							100,000
loss on extinguishment of debt							800,000
Debtor-in-Possession Financing, Borrowings Outstanding						$ 227,400,000
Long-term debt, face value										$ 263,900,000
Convertible debentures, interest rate				1.50%	1.50%
debt instrument net proceeds										$ 253,200,000
Debt issuance Percentage of Principal Amount										97.09%
Debt Instrument, Unamortized Discount (Premium), Net										$ 7,700,000
Convertible Debt, Noncurrent										208,600,000
Debt Instrument, Convertible, Carrying Amount of Equity Component										$ 55,300,000
Debt Instrument, Unamortized Discount				$ 22,700,000	$ 32,800,000
Debt Instrument, Convertible, Conversion Price										$ 20.61
Aggregate Principal Amount of Senior Notes, Redemption Price, Percentage				100.00%
Debt Instrument, Repurchased Face Amount							36,500,000
debt repurchase allocation - Debt portion							34,700,000
Debt repurchase allocation - Equity portion							$ 6,600,000
2.75% Convertible Debentures due November 1, 2031
Debt Instrument [Line Items]
Long-term debt, face value								$ 46,600,000	$ 395,500,000		$ 690,000,000
Convertible debentures, interest rate			2.75%	2.75%	2.75%						2.75%
Repayments of Convertible Debt	$ 331,200,000	$ 256,200,000	$ 38,300,000	$ 17,800,000	$ 38,300,000
debt instrument net proceeds											$ 676,100,000
Convertible Debt, Noncurrent											533,600,000
Debt Instrument, Convertible, Carrying Amount of Equity Component											$ 156,400,000
Debt Instrument, Unamortized Discount				$ 0	0
Principal Amount Per Note Used In Conversion Rate					$ 1,000
Minimum | Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage									130.00%
Debt Instrument Conversion Circumstance Number Of Trading Days					20 days
Minimum | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage					130.00%
Debt Instrument Conversion Circumstance Number Of Trading Days				20 days
Maximum | Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage									98.00%
Debt Instrument Conversion Circumstance Number Of Trading Days					30 days
Principal Amount Per Note Used In Conversion Rate									$ 1,000
Maximum | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage					98.00%
After auto spin-off [Member] | Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount									41.4576
After auto spin-off [Member] | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount										48.5216
Ending on Last Trading Day of Previous Fiscal Quarter [Member] | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument Conversion Circumstance Number Of Consecutive Trading Days				30 days
Before auto spin-off [Member] | Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount									36.7360
Before auto spin-off [Member] | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount										42.9978

Credit Facilities and Debt Cr_6

Credit Facilities and Debt Credit Facilities and Debt - 6% Senior Notes due 2024 (Details) - USD ($) $ in Thousands	1 Months Ended
	Jun. 30, 2016	Sep. 30, 2020	Sep. 30, 2019	Dec. 22, 2016	Jun. 21, 2016
Debt Instrument [Line Items]
Long-term Debt		$ 1,536,673	$ 1,936,406
Long-term debt, face value		$ 1,666,500	$ 2,137,000
5.375% Senior Notes due August 15, 2020
Debt Instrument [Line Items]
Convertible debentures, interest rate		5.375%	5.375%	5.375%
Debt Instrument, Unamortized Premium		$ 0	$ 0
6.0% Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent		$ 0	$ 298,529		$ 300,000
Convertible debentures, interest rate		6.00%	6.00%		6.00%
Proceeds from long-term debt, net of issuance costs	$ 297,500
Long-term debt, face value					$ 300,000
Debt Instrument, Repurchase Amount					313,500
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid					4,500
loss on extinguishment of debt					15,000
Debt Instrument, Unamortized Premium		$ 0	$ 0		13,500
Unamortized Loss Reacquired Debt, Noncurrent					$ 1,500

Credit Facilities and Debt Cr_7

Credit Facilities and Debt Credit and Debt Facilities - 1% Convertible Debentures due 2035 (Details) - USD ($)	1 Months Ended	3 Months Ended			9 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2017	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2017	Sep. 30, 2020	Sep. 30, 2019	Nov. 01, 2017	Mar. 13, 2017	Dec. 07, 2015	Oct. 24, 2011
Debt Instrument [Line Items]
Long-term debt, face value						$ 1,666,500,000	$ 2,137,000,000
Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Long-term debt, face value										$ 676,500,000
Convertible debentures, interest rate						1.00%	1.00%			1.00%
Proceeds from long-term debt, net of issuance costs							$ 663,800,000
Convertible Debt, Noncurrent										$ 495,400,000
Debt Instrument, Convertible, Carrying Amount of Equity Component										$ 181,100,000
Debt Instrument, Convertible, Conversion Price										$ 24.12
Convertible Debentures One Percent Due Twenty Thirty Five [Member] | Minimum
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage										130.00%
Debt Instrument Conversion Circumstance Number Of Trading Days							20 days
Convertible Debentures One Percent Due Twenty Thirty Five [Member] | Maximum
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage										98.00%
Debt Instrument Conversion Circumstance Number Of Trading Days							30 days
Principal Amount Per Note Used In Conversion Rate										$ 1,000
2.75% Convertible Debentures due November 1, 2031
Debt Instrument [Line Items]
Long-term debt, face value								$ 46,600,000		$ 395,500,000	$ 690,000,000
Convertible debentures, interest rate				2.75%		2.75%	2.75%				2.75%
Repayments of Convertible Debt		$ 331,200,000	$ 256,200,000	$ 38,300,000		$ 17,800,000	$ 38,300,000
Repayments of Debt	$ 46,600,000
Convertible Debt, Noncurrent											$ 533,600,000
Debt Instrument, Convertible, Carrying Amount of Equity Component											$ 156,400,000
Principal Amount Per Note Used In Conversion Rate							$ 1,000
Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt, face value									$ 350,000,000
Convertible debentures, interest rate						1.25%	1.25%		1.25%
Proceeds from long-term debt, net of issuance costs					$ 343,600,000
Convertible Debt, Noncurrent									$ 252,100,000
Debt Instrument, Convertible, Carrying Amount of Equity Component									$ 97,900,000
Debt Instrument, Convertible, Conversion Price									$ 19.69
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage							130.00%
Convertible Debentures 1.25% Due 2025 [Member] | Minimum
Debt Instrument [Line Items]
Debt Instrument Conversion Circumstance Number Of Trading Days						20 days
Term Loan Facility Due August Seventh Twenty Ninteen [Member]
Debt Instrument [Line Items]
Repayments of Debt							$ 472,500,000
Before auto spin-off [Member] | Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount										36.7360
Before auto spin-off [Member] | Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount									45.0106
After auto spin-off [Member] | Convertible Debentures One Percent Due Twenty Thirty Five [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount										41.4576
After auto spin-off [Member] | Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount									50.7957

Credit Facilities and Debt 5.62

Credit Facilities and Debt 5.625% Senior Notes due 2026 (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2020	Sep. 30, 2019	Dec. 22, 2016
5.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent		$ 496,148	$ 495,518	$ 500,000
Proceeds from issuance of senior notes	$ 495,000
Convertible debentures, interest rate		5.625%	5.625%	5.625%
5.375% Senior Notes due August 15, 2020
Debt Instrument [Line Items]
Convertible debentures, interest rate		5.375%	5.375%	5.375%
Change of Control [Member] | 5.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Aggregate Principal Amount of Senior Notes, Redemption Price, Percentage		101.00%
At any time and from time to time before December 15, 2021 [Member] | 5.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Aggregate Principal Amount of Senior Notes, Redemption Price, Percentage		105.625%
Asset Sale [Member] | 5.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Aggregate Principal Amount of Senior Notes, Redemption Price, Percentage		100.00%
Before December 15, 2021 [Member] | 5.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Aggregate Principal Amount of Senior Notes, Redemption Price, Percentage		100.00%
Aggregate Principal Amount of Senior Notes, Redemption of Principal Amount, Percentage		35.00%
Before December 15, 2021 [Member] | 5.625% Senior Notes due 2026 [Member] | Minimum
Debt Instrument [Line Items]
Aggregate Principal Amount of Senior Notes, Redemption of Principal Amount, Percentage		50.00%

Credit Facilities and Debt 1.25

Credit Facilities and Debt 1.25% Convertible Debentures due 2025 (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				9 Months Ended	12 Months Ended			65 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2018	Jun. 30, 2020	Mar. 31, 2020	Nov. 01, 2017	Mar. 13, 2017	Dec. 07, 2015	Jun. 01, 2015	Oct. 24, 2011
Debt Instrument [Line Items]
Long-term debt, face value						$ 1,666.5	$ 2,137
Stock Repurchased and Retired During Period, Shares		5,800,000				9,500,000	8,200,000	9,700,000	73,800,000
Stock Repurchased During Period, Value		$ 99.1				$ 169.2	$ 126.9	$ 136.1	$ 1,238.8
Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
debt repurchase allocation - Debt portion											$ 72.8
Debt repurchase allocation - Equity portion											39.5
Unamortized Loss Reacquired Debt, Noncurrent											16.7
debt issuance cost write off											0.7
loss on extinguishment of debt											2.8
Debtor-in-Possession Financing, Borrowings Outstanding											262.7
Long-term debt, face value													$ 350
Convertible debentures, interest rate						1.25%	1.25%						1.25%
Debt Instrument, Repurchase Amount											112.3
Debt Instrument, Repurchased Face Amount											87.3
Proceeds from long-term debt, net of issuance costs					$ 343.6
Convertible Debt, Noncurrent													$ 252.1
Debt Instrument, Convertible, Carrying Amount of Equity Component													$ 97.9
Debt Instrument, Convertible, Conversion Price													$ 19.69
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage							130.00%
Convertible Debentures 1.25% Due 2025 [Member] | Minimum
Debt Instrument [Line Items]
Debt Instrument Conversion Circumstance Number Of Trading Days						20 days
2.75% Convertible Debentures due November 1, 2031
Debt Instrument [Line Items]
Long-term debt, face value												$ 46.6		$ 395.5		$ 690
Convertible debentures, interest rate				2.75%		2.75%	2.75%									2.75%
Repayments of Convertible Debt	$ 331.2		$ 256.2	$ 38.3		$ 17.8	$ 38.3
Convertible Debt, Noncurrent																$ 533.6
Debt Instrument, Convertible, Carrying Amount of Equity Component																$ 156.4
Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
debt repurchase allocation - Debt portion											34.7
Debt repurchase allocation - Equity portion											6.6
Unamortized Loss Reacquired Debt, Noncurrent											2.5
debt issuance cost write off											0.1
loss on extinguishment of debt											0.8
Debtor-in-Possession Financing, Borrowings Outstanding										$ 227.4
Long-term debt, face value															$ 263.9
Convertible debentures, interest rate						1.50%	1.50%
Debt Instrument, Repurchase Amount											41.3
Debt Instrument, Repurchased Face Amount											$ 36.5
Convertible Debt, Noncurrent															208.6
Debt Instrument, Convertible, Carrying Amount of Equity Component															$ 55.3
Debt Instrument, Convertible, Conversion Price															$ 20.61
Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member] | Minimum
Debt Instrument [Line Items]
Ratio of Common Stock Closing Price to Debt Conversion Price, Percentage							130.00%
Debt Instrument Conversion Circumstance Number Of Trading Days						20 days
After auto spin-off [Member] | Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount													50.7957
After auto spin-off [Member] | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount															48.5216
Ending on Last Trading Day of Previous Fiscal Quarter [Member] | Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument Conversion Circumstance Number Of Consecutive Trading Days						30 days
Ending on Last Trading Day of Previous Fiscal Quarter [Member] | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument Conversion Circumstance Number Of Consecutive Trading Days						30 days
Before auto spin-off [Member] | Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount													45.0106
Before auto spin-off [Member] | Convertible Debentures One Point Five Percent Due November One Twenty Thirty Five [Member] [Member]
Debt Instrument [Line Items]
Convertible debt shares per $1,000 principal amount															42.9978

Financial Instruments and Hed_3

Financial Instruments and Hedging Activities - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Available for sale Securities, Weighted Average Maturity	3 months 21 days	6 months 10 days
Foreign currency exchange gain	$ 1.3	$ 1.1	$ (1.2)
Derivatives Not Designated as Hedges
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, Notional Amount	$ 40.7	$ 189.6
Derivatives Not Designated as Hedges | Maximum
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Maturity Period Of Foreign Currency Derivatives	90 days

Financial Instruments and Hed_4

Financial Instruments and Hedging Activities - Fair Value of Derivative Instruments (Details) - Foreign currency contracts - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Prepaid Expenses and Other Current Assets
Derivatives, Fair Value [Line Items]
Asset value of non-hedge derivative instruments	$ 109	$ 597
Accrued Expenses And Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	$ 92	$ 327

Financial Instruments and Hed_5

Financial Instruments and Hedging Activities - Activity of Derivative Instruments (Details) - Derivatives Not Designated as Hedges - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 40,700	$ 189,600
Foreign currency contracts | Other income, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ 379	$ 1,816	$ (3,616)

Fair Value Measures - Assets an

Fair Value Measures - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		$ 2,355,500	$ 2,143,400
Long-term debt, face value		$ 1,666,500	$ 2,137,000
Available for sale Securities, Weighted Average Maturity		3 months 21 days	6 months 10 days
Fair Value, Measurements, Recurring
Assets:
Money market funds		$ 182,645	$ 217,861
Bank Time Deposits, Fair Value Disclosure		95,180	115,913
Commercial Paper, Fair value		33,290	77,494
Financial Instruments, Owned, Corporate Debt, at Fair Value		15,480	37,566
Foreign Currency Contract, Asset, Fair Value Disclosure		109	597
Total assets at fair value		326,704	449,431
Foreign Currency Contracts, Liability, Fair Value Disclosure	[1]	(92)	(327)
Liabilities:
Contingent earn-out		(1,796)	(2,550)
Total liabilities at fair value		(1,888)	(2,877)
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets:
Money market funds		182,645	217,861
Bank Time Deposits, Fair Value Disclosure		0	0
Commercial Paper, Fair value		0	0
Financial Instruments, Owned, Corporate Debt, at Fair Value		0	0
Foreign Currency Contract, Asset, Fair Value Disclosure		0	0
Total assets at fair value		182,645	217,861
Foreign Currency Contracts, Liability, Fair Value Disclosure		0	0
Liabilities:
Contingent earn-out		0	0
Total liabilities at fair value		0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets:
Money market funds		0	0
Bank Time Deposits, Fair Value Disclosure		95,180	115,913
Commercial Paper, Fair value		33,290	77,494
Financial Instruments, Owned, Corporate Debt, at Fair Value		15,480	37,566
Foreign Currency Contract, Asset, Fair Value Disclosure		109	597
Total assets at fair value		144,059	231,570
Foreign Currency Contracts, Liability, Fair Value Disclosure		(92)	(327)
Liabilities:
Contingent earn-out		0	0
Total liabilities at fair value		(92)	(327)
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets:
Money market funds		0	0
Bank Time Deposits, Fair Value Disclosure		0	0
Commercial Paper, Fair value		0	0
Financial Instruments, Owned, Corporate Debt, at Fair Value		0	0
Foreign Currency Contract, Asset, Fair Value Disclosure		0	0
Total assets at fair value		0	0
Foreign Currency Contracts, Liability, Fair Value Disclosure		0	0
Liabilities:
Contingent earn-out		(1,796)	(2,550)
Total liabilities at fair value		(1,796)	(2,550)
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Amortized Cost Basis		33	77
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Amortized Cost Basis		$ 15	$ 38
Commercial paper, corporate notes and bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale Securities, Weighted Average Maturity		3 months 21 days	6 months 12 days
[1]	years as of September 30, 2020 and 0.53 years as of September 30, 2019 .

Fair Value Measures - Changes i

Fair Value Measures - Changes in Fair Value of Contingent Earn-Out Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent and deferred acquisition payments	$ 4,224	$ 17,470
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	2,550	4,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Earn-out Liability		1,500
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements		(2,550)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(4)
Charges (credits) to acquisition-related costs, net	(750)	(400)
Ending balance	1,796	$ 2,550
Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent and deferred acquisition payments	$ 3,000

Restructuring and Other Charg_3

Restructuring and Other Charges, Net - Additional Information (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Restructuring Cost and Reserve [Line Items]
Current Fiscal Year End Date	--09-30
Restructuring and other charges, net	$ (10,836)	$ (16,437)	$ (31,228)
Restructuring Reserve	$ 16,856	$ 7,209	$ 14,829	$ 9,668
Number of personnel eliminated	191	305	1,250
Tangible Asset Impairment Charges			$ 7,100
Restructuring and other charges, net	$ 17,680	$ 29,147	52,846
Personnel
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	(5,305)	(14,212)	(27,360)
Restructuring and Related Cost, Incurred Cost	5,305	14,212	27,360
Restructuring Reserve	1,243	3,587	8,335	1,509
Facilities
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	(5,531)	(2,225)	(3,868)
Restructuring and Related Cost, Incurred Cost	5,531	2,225	3,868
Restructuring Reserve	15,613	3,622	6,494	$ 8,159
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	6,844	12,710	21,618
Other Expense [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	2,000	3,300	4,800
Malware Incident - Professional Service Charges [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	300	500
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	(2,712)	(3,803)	(11,060)
Corporate | Personnel
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1,935	3,039	10,107
Corporate | Facilities
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	777	764	953
Corporate | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	6,844	9,404	14,515
Chief Executive Officer [Member] | Corporate | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		$ 9,900	$ 5,700
Other Restructuring [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	$ 5,100

Restructuring and Other Charg_4

Restructuring and Other Charges, Net - Accrual Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Lease Obligation Incurred	$ 11,674
Restructuring Reserve [Roll Forward]
Beginning balance	7,209	$ 14,829	$ 9,668
Restructuring and other charges, net	10,836	16,437	31,228
Non-cash adjustment	1,052	(102)	(998)
Cash payments	(13,915)	(23,955)	(25,069)
Ending balance	16,856	7,209	14,829
Personnel
Restructuring Cost and Reserve [Line Items]
Lease Obligation Incurred	0
Restructuring Reserve [Roll Forward]
Beginning balance	3,587	8,335	1,509
Restructuring and other charges, net	5,305	14,212	27,360
Non-cash adjustment	0	0	0
Cash payments	(7,649)	(18,960)	(20,534)
Ending balance	1,243	3,587	8,335
Facilities
Restructuring Cost and Reserve [Line Items]
Lease Obligation Incurred	11,674
Restructuring Reserve [Roll Forward]
Beginning balance	3,622	6,494	8,159
Restructuring and other charges, net	5,531	2,225	3,868
Non-cash adjustment	1,052	(102)	(998)
Cash payments	(6,266)	(4,995)	(4,535)
Ending balance	$ 15,613	$ 3,622	$ 6,494

Restructuring and Other Charg_5

Restructuring and Other Charges, Net - Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	$ (17,680)	$ (29,147)	$ (52,846)
Restructuring and other charges, net	10,836	16,437	31,228
Health Care [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	(4,772)	(4,870)	(11,588)
Restructuring and other charges, net	4,772	4,870	11,588
Enterprise
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	(3,415)	(5,970)	(6,460)
Restructuring and other charges, net	3,415	5,970	6,460
Other Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	(63)	(5,100)	(9,223)
Restructuring and other charges, net	(63)
Restructuring and Related Cost, Incurred Cost		1,794	2,120
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	(9,556)	(13,207)	(25,575)
Restructuring and other charges, net	2,712	3,803	11,060
Personnel
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	5,305	14,212	27,360
Restructuring and Related Cost, Incurred Cost	5,305	14,212	27,360
Personnel | Health Care [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1,953	4,679	11,563
Personnel | Enterprise
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1,417	5,037	4,217
Personnel | Other Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net		1,457	1,473
Restructuring and Related Cost, Incurred Cost	0
Personnel | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1,935	3,039	10,107
Facilities
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	5,531	2,225	3,868
Restructuring and Related Cost, Incurred Cost	5,531	2,225	3,868
Facilities | Health Care [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	2,819	191	25
Facilities | Enterprise
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1,998	933	2,243
Facilities | Automotive
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net		337	647
Facilities | Other Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(63)
Facilities | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	777	764	953
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	6,844	12,710	21,618
Other Restructuring [Member] | Health Care [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	0	0	0
Other Restructuring [Member] | Enterprise
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	0	0	0
Other Restructuring [Member] | Other Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net		3,306	7,103
Other Restructuring Costs	0
Other Restructuring [Member] | Corporate
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	$ 6,844	$ 9,404	$ 14,515

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Supplemental Cash Flow Information [Abstract]
Interest paid	$ 50,346	$ 72,630	$ 93,121
Income taxes paid	$ 30,918	$ 19,439	$ 13,758

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended			65 Months Ended
	Sep. 30, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2018	Apr. 29, 2013
Stockholders Equity Note [Line Items]
Stock Repurchase Program, Number of Shares Authorized, Value						$ 500,000
Preferred stock, shares authorized		40,000,000
Preferred stock, par value		$ 0.001
Stock Repurchased and Retired During Period, Shares	5,800,000	9,500,000	8,200,000	9,700,000	73,800,000
Stock Repurchased During Period, Value	$ 99,100	$ 169,200	$ 126,900	$ 136,100	$ 1,238,800
Document Period End Date		Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		3,830	3,314	2,963
Payments for Repurchase of Common Stock		$ 169,217	$ 126,938	$ 136,090
Series A Preferred Stock [Member]
Stockholders Equity Note [Line Items]
Preferred stock, shares authorized		1,000,000
Preferred stock, par value		$ 0.001
Common Stock
Stockholders Equity Note [Line Items]
Stock Repurchased and Retired During Period, Shares		9,457,000	8,160,000	9,698,000

Stockholders' Equity Share Repu

Stockholders' Equity Share Repurchases (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended			65 Months Ended
	Sep. 30, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2018	Aug. 01, 2018	Apr. 29, 2015	Apr. 29, 2013
Share Repurchases [Line Items]
Stock Repurchase Program, Number of Shares Authorized, Value								$ 500,000
Stock Repurchase Program, Authorized Amount						$ 500,000	$ 500,000
Stock Repurchased and Retired During Period, Shares	5,800,000	9,500,000	8,200,000	9,700,000	73,800,000
Stock Repurchased During Period, Value	$ 99,100	$ 169,200	$ 126,900	$ 136,100	$ 1,238,800
Document Period End Date		Sep. 30, 2020
Stock Repurchase Program, Remaining Value of Shares Authorized to be Repurchased		$ 261,200
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		3,830	3,314	2,963
Payments for Repurchase of Common Stock		$ 169,217	$ 126,938	$ 136,090

Stockholders' Equity Preferred

Stockholders' Equity Preferred Stock (Details)	Sep. 30, 2020$ / sharesshares
Class of Stock [Line Items]
Preferred stock, par value	$ 0.001
Preferred stock, shares authorized | shares	40,000,000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value	$ 0.001
Preferred Stock, Number of Votes, Per Share	$ 1,000
Preferred stock, shares authorized | shares	1,000,000
Series B [Member]
Class of Stock [Line Items]
Preferred stock, par value	$ 0.001
Preferred stock, shares authorized | shares	15,000,000
Minimum | Series A Preferred Stock [Member]
Class of Stock [Line Items]
Dividend Equivalents, per Share	$ 1
Maximum | Series A Preferred Stock [Member]
Class of Stock [Line Items]
Dividend Equivalents, per Share	$ 1,000

earnings per share (Details)

earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Basic (per share)	$ (0.08)	$ 0.06	$ (0.07)	$ 0.19	$ 0.01	$ 0	$ (0.10)	$ 0.05	$ 0.08	$ 0.75	$ (0.55)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									$ 28,782	$ (12,198)	$ (236,837)
Net (loss) income from discontinued operations									(7,386)	226,008	76,909
Net income (loss)	$ (22,751)	$ 16,662	$ (20,006)	$ 54,877	$ 3,005	$ (687)	$ (28,397)	$ 13,881	$ 21,396	$ 213,810	$ (159,928)
Basic (in shares)	282,556	281,281	282,576	284,130	285,754	285,942	285,866	287,796	282,644	286,347	291,318
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities									3,286	0	0
Weighted Average Number Diluted Shares Outstanding Adjustment									6,064	0	0
Diluted (in shares)	282,556	287,852	282,576	289,453	291,598	285,942	285,866	292,359	291,994	286,347	291,318
Income (Loss) from Continuing Operations, Per Basic Share									$ 0.10	$ (0.04)	$ (0.81)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share									(0.02)	0.79	0.26
Income (Loss) from Continuing Operations, Per Diluted Share									0.10	(0.04)	(0.81)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share									(0.03)	0.79	0.26
Diluted (per share)	$ (0.08)	$ 0.06	$ (0.07)	$ 0.19	$ 0.01	$ 0	$ (0.10)	$ 0.05	$ 0.07	$ 0.75	$ (0.55)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									453	1,047	528
Weighted Average Number of Shares, Contingently Issuable									9	1,786	4,434

Stock-Based Compensation - Incl

Stock-Based Compensation - Included in Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation	$ 133,294	$ 119,255	$ 127,043
Cost of product and licensing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation	510	855	814
Professional Services And Hosting
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation	24,887	26,647	29,053
Maintenance And Support
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation	1,663	1,314	3,322
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation	34,902	22,508	26,968
Selling and Marketing Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation	32,040	30,394	33,150
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation	$ 39,292	$ 37,537	$ 33,736

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended			65 Months Ended
	Sep. 30, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2018
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Repurchased and Retired During Period, Shares	5,800,000	9,500,000	8,200,000	9,700,000	73,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 15.39	$ 17.18	$ 20.04	$ 17.31	$ 17.31
Number of Shares
Beginning Balance		11,302	19,144	23,807
Exercised		(3,830)	(3,314)	(2,963)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price		$ 17.18	$ 7.22	$ 2.61
Equitable Adjustment		1,883
Expired			(4,528)	(1,700)
Ending Balance	23,807	9,355	11,302	19,144	19,144
Exercisable		9,355	11,302	19,144	19,144
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price			$ 17.89	$ 15.99
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term		1 year 7 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		$ 0.1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price		$ 17.18
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		1 year 7 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value		$ 0.1

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock Options (Details) - $ / shares	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	3,830	3,314	2,963
Share Price	$ 33.19

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Activity Relating to Restricted Units (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Equitable Adjustment	1,883
Number of Shares Underlying Restricted Units - Contingent Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning Balance	1,991,325	3,039,568	5,043,931
Granted	1,067,900	1,342,836	2,175,537
Earned/released	(303,198)	(1,405,485)	(2,092,862)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		296,759
Forfeited	(438,981)	(688,835)	(2,087,038)
Ending Balance	2,620,120	1,991,325	3,039,568
Weighted average remaining contractual term of outstanding Restricted Units	1 year 4 months 24 days
Unearned stock based compensation expense	$ 19.1
Aggregate intrinsic value of outstanding Restricted Units	$ 87
Equitable Adjustment	303,074
Time Lapse Restricted Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning Balance	8,998,944	6,872,087	6,477,164
Granted	6,401,949	9,500,077	8,876,712
Earned/released	(8,106,783)	(6,383,908)	(7,156,468)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		296,759
Forfeited	(1,452,467)	(1,286,071)	(1,325,321)
Ending Balance	7,157,649	8,998,944	6,872,087
Weighted average remaining contractual term of outstanding Restricted Units	1 year 8 months 12 days
Unearned stock based compensation expense	$ 79.7
Aggregate intrinsic value of outstanding Restricted Units	$ 237.6
Equitable Adjustment	(1,316,006)

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Activity Relating to Restricted Units (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended			65 Months Ended
	Sep. 30, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchased and Retired During Period, Shares	5,800,000	9,500,000	8,200,000	9,700,000	73,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		3,830	3,314	2,963
Stock Repurchased During Period, Value	$ 99.1	$ 169.2	$ 126.9	$ 136.1	$ 1,238.8
Share Price		$ 33.19

Stock-Based Compensation - Su_5

Stock-Based Compensation - Summary of Weighted-Average Grant-Date Fair Value and Intrinsic Value of Restricted Units Vested (Detail) - Restricted Stock Units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value per share	$ 19.51	$ 16.52	$ 15.47
Total intrinsic value of shares vested (in millions)	$ 164.1	$ 125.2	$ 146.5

Stock-Based Compensation Stock-

Stock-Based Compensation Stock-Based Compensation - Summary of Weighted Average Grant-Date Fair Value, Shares Issued and Total Stock-Based Compensation Expense Recognized Related to the Plan (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense (in millions)	$ 133,294	$ 119,255	$ 127,043
1995 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value per share	$ 6.90	$ 3.76	$ 4
Total shares issued (in millions)	1	1.2	1.3
Total stock-based compensation expense (in millions)	$ 4,200	$ 4,500	$ 5,200

Stock-Based Compensation Stoc_2

Stock-Based Compensation Stock-Based Compensation - Weighted Average Assumptions Used to Estimate Fair Value of Purchase Rights Ganted (Details) - 1995 Employee Stock Purchase Plan	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Expected volatility	39.80%	27.80%	32.10%
Average risk-free interest rate	0.90%	2.20%	2.00%
Expected term (in years)	6 months	6 months	6 months

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended			65 Months Ended
	Sep. 30, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2018	Jan. 27, 2015	Jan. 29, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchased During Period, Value	$ 99,100	$ 169,200	$ 126,900	$ 136,100	$ 1,238,800
Share Price		$ 33.19
Cancellation of Restricted Stock and Repurchase of Common Stock at Cost for Employee Tax Withholding, Value		$ (56,460)	$ 42,554	$ 52,336
Maximum number of shares authorized		9,000,000
Document Period End Date		Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant		12,800,000
Stock Repurchased and Retired During Period, Shares	5,800,000	9,500,000	8,200,000	9,700,000	73,800,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Average risk-free interest rate		1.40%	2.23%
Expected term (in years)		2 years 8 months 20 days	1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Average risk-free interest rate		1.62%	3.02%
Expected term (in years)		3 years	3 years
1995 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield		0.00%	0.00%	0.00%
Maximum number of shares authorized						20,000,000
Common stock price, percentage of the closing price on applicable offering commencement date							85.00%
Common stock price, percentage of closing price on applicable offering termination date						85.00%
Common stock reserved for issuance		3,600,000
Average risk-free interest rate		0.90%	2.20%	2.00%
Expected term (in years)		6 months	6 months	6 months
Weighted-average grant-date fair value per share		$ 6.90	$ 3.76	$ 4
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cancellation of Restricted Stock and Repurchase of Common Stock at Cost for Employee Tax Withholding, Value		$ 56,500
Weighted-average grant-date fair value per share		$ 19.51	$ 16.52	$ 15.47
Cancellation of Restricted Stock and Repurchase of Common Stock at Cost for Employee Tax Withholding, Shares		2,900,000
Time Lapse Restricted Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized			296,759
Unearned stock based compensation expense		$ 79,700
Weighted average remaining recognition period		1 year 8 months 12 days
Aggregate intrinsic value of outstanding Restricted Units		$ 237,600
Number of restricted stock awards granted		6,401,949	9,500,077	8,876,712

Stock-Based Compensation stoc_3

Stock-Based Compensation stock-based compensation performance based on the market return (Details)	12 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Summary of Stock Options Activity	The table below summarizes activities related to stock options for the years ended September 30, 2020 , 2019 and 2018 : Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (a) Outstanding at September 30, 2017 23,807 $ 15.39 Exercised (2,963 ) $ 2.61 Expired (1,700 ) $ 15.99 Outstanding at September 30, 2018 19,144 $ 17.31 Exercised (3,314 ) $ 7.22 Expired (4,528 ) $ 17.89 Outstanding at September 30, 2019 11,302 $ 20.04 Exercised (3,830 ) $ 17.18 Equitable Adjustment - Cerence Spin-off (b) 1,883 Outstanding at September 30, 2020 9,355 $ 17.18 1.6 years $ 0.1 million Exercisable at September 30, 2020 9,355 $ 17.18 1.6 years $ 0.1 million Exercisable at September 30, 2019 11,302 Exercisable at September 30, 2018 19,144 (a)

Stock-Based Compensation Stoc_4

Stock-Based Compensation Stock-Based Compensation TSR valuation (Details)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
dividend yield	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	27.73%	27.30%
Average risk-free interest rate	1.40%	2.23%
Expected term (in years)	2 years 8 months 20 days	1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	28.24%	30.90%
Average risk-free interest rate	1.62%	3.02%
Expected term (in years)	3 years	3 years

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	Sep. 30, 2020USD ($)
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals	$ 12.4

Pension and Other Post-Retire_2

Pension and Other Post-Retirement Benefits - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Deferred Compensation Arrangement with Individual, Employer Contribution Percentage	100.00%
Deferred Compensation Arrangement with Individual Employer, Contribution Percentage of Eligible Salary	3.00%
Deferred Compensation Arrangement with Individual, Employer Contribution Percentage,50%	50.00%
Deferred Compensation Arrangement with Individual Employer, Contribution Percentage of Eligible Salary 50%match	2.00%
Deferred Compensation Arrangement with Individual Employer, Contribution Percentage of Eligible Salary total matched	4.00%
Total contributions to 401(k) Plan	$ 12	$ 7.3	$ 6.1
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 0.4	0.5	$ 0.1
Document Period End Date	Sep. 30, 2020
Defined Benefit Plan, Benefit Obligation	$ 35.4	35.2
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ (13.2)	$ (12.6)

Income Taxes - Components of In

Income Taxes - Components of Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Domestic	$ (21,170)	$ (3,325)	$ (230,955)
Foreign	31,200	3,232	(83,042)
Income (loss) before income taxes	$ 10,030	$ (93)	$ (313,997)

Income Taxes - Components of _2

Income Taxes - Components of Income Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Current:
Federal	$ 6,654	$ 5,023	$ (5,084)
State	740	1,214	(2,007)
Foreign	13,791	18,305	18,338
Current tax provision (benefit)	21,185	24,542	11,247
Deferred:
Federal	(17,969)	7,727	(84,569)
State	(13,216)	1,477	1,986
Foreign	(8,752)	(21,641)	(5,824)
Deferred tax (benefit) provision	(39,937)	(12,437)	(88,407)
(Benefit) provision for income taxes	$ (18,752)	$ 12,105	$ (77,160)
Effective tax rate	(187.00%)	(13016.10%)	24.60%
TCJA
Current:
Current tax provision (benefit)	$ 5,800
Deferred:
Deferred tax (benefit) provision	$ 92,900

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Effective Tax Rate to Statutory Federal Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Document Period End Date	Sep. 30, 2020
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	24.50%
Federal tax provision (benefit) at statutory rate	$ 2,106	$ (20)	$ (77,029)
State tax, net of federal benefit	(9,740)	2,328	(508)
Foreign tax rate and other foreign related tax items	(4,047)	7,708	(4,275)
Stock-based compensation	(3,830)	3,368	3,290
Non-deductible expenditures	481	2,696	1,927
Change in U.S. and foreign valuation allowance	(28,709)	188,510	57,281
Effective Income Tax Rate Reconciliation, Disposition of Asset, Amount	(14,800)	(23,428)	0
income tax reconciliation, uncertain tax position	18,020	4,428	4,415
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	0	0	(87,058)
Effective Income Tax Rate Reconciliation, Tax Holiday, Amount	6,619	5,023	0
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount	0	0	28,640
Income Tax Reconciliation, Capital Loss	10,443	(179,635)	0
Other	102	(1,000)	(583)
(Benefit) provision for income taxes	$ (18,752)	$ 12,105	$ (77,160)

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 121,375	$ 166,224
Deferred Tax Assets, Capital Loss Carryforwards	169,480	188,320
Federal and state credit carryforwards	44,181	43,897
Accrued expenses and other reserves	19,703	33,150
Deferred Tax Assets, Deferred Income	47,818	130,361
Deferred compensation	20,088	22,917
Other	18,697	11,579
Total deferred tax assets	417,398	490,919
Valuation allowance for deffered tax assets	(230,322)	(303,378)
Net deferred tax assets	187,076	187,541
Deferred Tax Liabilities, Other	70,116	54,216
Deferred tax liabilities:
Depreciation	(20,781)	(16,833)
Convertible debt	(86,667)	(87,046)
Acquired intangibles	(56,794)	(7,517)
Reported as:
Deferred Tax Liabilities, Net	$ 22,298	$ 76,145

Income Taxes - Aggregate Change

Income Taxes - Aggregate Changes in Balance of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 2,100	$ 1,400	$ 800
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance, beginning of year	24,111	19,491
Increases for tax positions taken during the current period	6,866	5,517
Increases for interest and penalty charges	38,006	0
Decreases for tax settlements and lapse in statutes	413	(37)
Balance, end of year	60,481	24,111	$ 19,491
Unrecognized Tax Benefit, Increase Resulting from Acquisitions	$ 8,915	$ (860)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended			65 Months Ended
	Sep. 30, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2018
Income Tax Contingency [Line Items]
Foreign tax rate and other foreign related tax items		$ (4,047)	$ 7,708	$ (4,275)
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		$ 73,100
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	21.00%	24.50%
Subsidiary or Equity Method Investee, Deferred Income Tax Provision on Gain (Loss) Recognized, Amount			$ 857,800
Stock Repurchased During Period, Value	$ 99,100	$ 169,200	126,900	$ 136,100	$ 1,238,800
Document Period End Date		Sep. 30, 2020
(Benefit) provision for income taxes		$ 18,752	(12,105)	77,160
Undistributed earnings of foreign subsidiaries		294,000
Deferred tax assets valuation allowance		230,322	303,378
Deferred Tax Asset, Parent's Basis in Discontinued Operation			73,800
Unrecognized tax benefits potential to favorably impact effective tax rate			60,500
Unrecognized tax benefits, interest and penalties accrued		8,100	8,900
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense		2,100	1,400	$ 800
Investment Tax Credit Carryforward [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards		8,400	14,300
United States
Income Tax Contingency [Line Items]
Deferred tax assets valuation allowance		198,900	269,600
Net operating loss carryforwards		370,500	551,100
United States | Research and Development
Income Tax Contingency [Line Items]
Net operating loss carryforwards		56,600	27,700
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards		196,000	194,600
State | Research and Development
Income Tax Contingency [Line Items]
Net operating loss carryforwards		13,100	3,900
Foreign Tax Authority [Member]
Income Tax Contingency [Line Items]
Deferred tax assets valuation allowance		31,400	33,800
Net operating loss carryforwards		$ 154,800	$ 191,700

Related Party Transaction (Deta

Related Party Transaction (Details) - Magnet [Domain] - USD ($) $ in Millions	3 Months Ended			9 Months Ended	12 Months Ended
	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2018	Sep. 30, 2018
Licensed Technology
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party		$ 1.5	$ 3.5		$ 5
Maximum | Service Agreements [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	$ 2			$ 2

Segment and Geographic Inform_3

Segment and Geographic Information and Significant Customers - Segment Profit to Income Before Income Taxes (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2017	Sep. 30, 2020		Sep. 30, 2019		Sep. 30, 2018
Segment Reporting Information [Line Items]
Total segment revenues	[1]									$ 1,479,200		$ 1,522,807		$ 1,577,077
Revenues		$ (352,931)	$ (338,398)	$ (369,337)	$ (418,233)	$ (387,575)	$ (377,437)	$ (336,584)	$ (419,675)	(1,478,899)	[1]	(1,521,271)	[1]	(1,567,600)	[1]
Segment profit										465,399		484,250		477,045
Corporate expenses and other, net										(119,945)		(137,558)		(183,657)
Acquisition-related revenues and costs of revenue adjustment										(301)		(1,536)		(9,477)
Non-cash stock based compensation										(133,294)		(119,255)		(127,043)
Amortization of intangible assets										(78,707)		81,622		(105,375)
Acquisition-related costs, net										(2,884)		(7,965)		(12,010)
Restructuring and other charges, net										(17,680)		(29,147)		(52,846)
Goodwill and Intangible Asset Impairment										0		0		(170,941)
Other income (expense), net										(102,558)		(107,260)		(129,693)
Income (loss) before income taxes										10,030		(93)		(313,997)
Healthcare
Segment Reporting Information [Line Items]
Total segment revenues										915,332	[1]	950,593		984,819	[1]
Revenues										(915,332)		(949,730)
Segment profit										298,751		333,526		322,715
Enterprise
Segment Reporting Information [Line Items]
Total segment revenues										529,978	[1]	510,753		483,194	[1]
Revenues										(529,677)		(510,078)
Segment profit										146,923		131,169		130,173
Other Segments [Member]
Segment Reporting Information [Line Items]
Total segment revenues										33,890	[1]	61,461		109,064	[1]
Segment profit										19,725		19,555		24,157
Series of Individually Immaterial Business Acquisitions [Member]
Segment Reporting Information [Line Items]
Revenues										$ 301	[1]	$ (1,536)		$ (9,477)	[1]
[1]	Segment revenues differ from reported revenues due to certain revenue adjustments related to acquisitions that would otherwise have been recognized but for the purchase accounting treatment of the business combinations. These revenues are included to allow for more complete comparisons to the financial results of historical operations and in evaluating management performance.

Segment and Geographic Inform_4

Segment and Geographic Information and Significant Customers - Classification of Revenue by Major Geographic Areas (Detail) - USD ($) $ in Thousands

3 Months Ended

12 Months Ended

Sep. 30, 2020

Jun. 30, 2020

Mar. 31, 2020

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2017

Sep. 30, 2020

Sep. 30, 2019

Sep. 30, 2018

Revenues from External Customers and Long-Lived Assets [Line Items]

Revenues

$ 352,931

$ 338,398

$ 369,337

$ 418,233

$ 387,575

$ 377,437

$ 336,584

$ 419,675

$ 1,478,899

[1]

$ 1,521,271

[1]

$ 1,567,600

[1]

UNITED STATES

Revenues from External Customers and Long-Lived Assets [Line Items]

Revenues

1,185,760

1,237,406

1,255,203

International [Member]

Revenues from External Customers and Long-Lived Assets [Line Items]

Revenues

$ 293,139

$ 283,865

$ 312,397

[1]

Segment revenues differ from reported revenues due to certain revenue adjustments related to acquisitions that would otherwise have been recognized but for the purchase accounting treatment of the business combinations. These revenues are included to allow for more complete comparisons to the financial results of historical operations and in evaluating management performance.

Segment and Geographic Inform_5

Segment and Geographic Information and Significant Customers - Location of Long Lived Assets Including Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	$ 2,857,347	$ 2,873,972
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	2,254,424	2,086,932
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 602,923	$ 787,040

Quarterly Data Derived from Una

Quarterly Data Derived from Unaudited Consolidated Financial Statements with All Recurring Adjustments (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2017	Sep. 30, 2020		Sep. 30, 2019		Sep. 30, 2018
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 352,931	$ 338,398	$ 369,337	$ 418,233	$ 387,575	$ 377,437	$ 336,584	$ 419,675	$ 1,478,899	[1]	$ 1,521,271	[1]	$ 1,567,600	[1]
Gross Profit	199,656	194,216	212,244	233,844	219,240	205,667	177,325	235,555	839,960		837,787		824,198
Net income (loss)	$ (22,751)	$ 16,662	$ (20,006)	$ 54,877	$ 3,005	$ (687)	$ (28,397)	$ 13,881	21,396		213,810		(159,928)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									$ 28,782		$ (12,198)		$ (236,837)
Net income (loss) per share:
Basic (per share)	$ (0.08)	$ 0.06	$ (0.07)	$ 0.19	$ 0.01	$ 0	$ (0.10)	$ 0.05	$ 0.08		$ 0.75		$ (0.55)
Income (Loss) from Continuing Operations, Per Basic Share									0.10		(0.04)		(0.81)
Diluted (per share)	$ (0.08)	$ 0.06	$ (0.07)	$ 0.19	$ 0.01	$ 0	$ (0.10)	$ 0.05	0.07		0.75		(0.55)
Income (Loss) from Continuing Operations, Per Diluted Share									$ 0.10		$ (0.04)		$ (0.81)
Weighted Average Number of Shares Outstanding:
Basic (in shares)	282,556	281,281	282,576	284,130	285,754	285,942	285,866	287,796	282,644		286,347		291,318
Diluted (in shares)	282,556	287,852	282,576	289,453	291,598	285,942	285,866	292,359	291,994		286,347		291,318
[1]	Segment revenues differ from reported revenues due to certain revenue adjustments related to acquisitions that would otherwise have been recognized but for the purchase accounting treatment of the business combinations. These revenues are included to allow for more complete comparisons to the financial results of historical operations and in evaluating management performance.

Operating Leases (Details)

Operating Leases (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2020USD ($)
Lessee, Lease, Description [Line Items]
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals	$ 12,400
Operating Lease, Weighted Average Remaining Lease Term	4 years 8 months 12 days
Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year	$ 32,436
Lessee, Operating Lease, Liability, to be Paid, Year Two	26,967
Lessee, Operating Lease, Liability, to be Paid, Year Three	20,206
Lessee, Operating Lease, Liability, to be Paid, Year Four	16,492
Lessee, Operating Lease, Liability, to be Paid, Year Five	13,893
Lessee, Operating Lease, Liability, to be Paid, after Year Five	42,889
Lessee, Operating Lease, Liability, to be Paid	$ 152,883
Operating Lease, Weighted Average Discount Rate, Percent	3.80%
Operating Leases, Rent Expense	$ 32,500
Operating Lease, Payments	33,200
Restructuring Operating Leases [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year	4,492
Lessee, Operating Lease, Liability, to be Paid, Year Two	3,805
Lessee, Operating Lease, Liability, to be Paid, Year Three	3,440
Lessee, Operating Lease, Liability, to be Paid, Year Four	1,996
Lessee, Operating Lease, Liability, to be Paid, Year Five	1,346
Lessee, Operating Lease, Liability, to be Paid, after Year Five	1,843
Lessee, Operating Lease, Liability, to be Paid	16,922
Non-Restructuring Operating Leases [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year	27,944
Lessee, Operating Lease, Liability, to be Paid, Year Two	23,162
Lessee, Operating Lease, Liability, to be Paid, Year Three	16,766
Lessee, Operating Lease, Liability, to be Paid, Year Four	14,496
Lessee, Operating Lease, Liability, to be Paid, Year Five	12,547
Lessee, Operating Lease, Liability, to be Paid, after Year Five	41,046
Lessee, Operating Lease, Liability, to be Paid	$ 135,961