Disposition of Business (Notes)	12 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Disposition of Business Sale of Imaging BusinessOn November 7, 2018, our Board of Directors approved the divestiture of our Imaging business. On November 11, 2018, we entered into a sale agreement (the “Agreement”) with Project Leopard AcquireCo Limited, a private limited company incorporated under the laws of England and Wales (and an affiliate of Kofax, Inc.), relating to the sale of our Imaging business.On February 1, 2019, we completed the sale of the business and received approximately $400 million, after estimated transaction expenses, and subject to post-closing finalization of those adjustments as set forth in the Agreement. As a result, we recorded a gain of approximately $102.4 million, which is included within net income from discontinued operations. There are a number of working capital and other adjustments under the agreement and related ancillary agreements. The post-closing adjustments under the agreement did not have a material impact on our consolidated financial statements.For all periods presented, Imaging's results of operations have been included within discontinued operations and its assets and liabilities within held for sale on our consolidated financial statements.The following table summarizes the results of the discontinued operations (dollars in thousands): From October 1, 2018 to February 1, 2019 Fiscal Year 2018 Fiscal Year 2017 (ASC 606) (ASC 605) (ASC 605)Major line items constituting net income of Imaging:     Revenue (a)$67,430 $209,363 $211,187Cost of revenue16,946 48,183 49,962Research and development7,557 26,588 26,172Sales and marketing (a)28,433 76,593 73,760General and administrative1,997 3,890 3,612Amortization of intangible assets5,219 17,096 21,056Acquisition-related costs, net(386) 8 32Restructuring and other related charges13,251 6,472 1,131Other— 44 (193)(Loss) income from discontinued operations before income taxes(a)(5,587) 30,489 35,655(Benefit) provision for income taxes(2,688) 5,513 8,310Gain on disposition102,371 — —Net income from discontinued operations$99,472 $24,976 $27,345      Supplemental Information:     Depreciation$391 $1,995 $2,397Amortization$6,569 $23,083 $28,017Stock compensation$7,103 $7,876 $11,371Capital expenditures for all periods presented were de minimis. (a) As more fully described in Note 2, as a result of the adoption of ASC 606 using the modified retrospective approach, Revenue for fiscal year 2019 reflected an increase of $2.4 million due to the upfront recognition of term licenses and the re-allocation of contract consideration to performance obligations based upon standalone selling prices; Sales and marketing expense for fiscal year, 2019 reflected a decrease of $1.4 million due to the capitalization and amortization of commission expense; and the provision for income taxes for fiscal year 2019 reflected an increase in tax benefit of $1.6 million related to the tax effect of the ASC 606 adjustments.The following table summarizes the assets and liabilities included within discontinued operations (dollars in thousands): September 30, 2018 (ASC 605)Major classes of Imaging assets: Accounts receivable, net$30,959Prepaid expenses and other current assets3,443Land, building and equipment, net2,442Goodwill257,352Intangible assets, net99,507Other assets196Total assets classified as held for sale$393,899  Major classes of Imaging liabilities: Accounts payable$3,604Accrued expenses and other current liabilities12,304Deferred revenue107,965Other2,658Total liabilities classified as held for sale$126,531Spin-off of AutomotiveAs more fully disclosed in Note 23, on November 19, 2018, we announced our intent to spin off our Automotive business into an independent publicly traded company through a pro rata distribution to our common stockholders. The spin-off was completed on October 1, 2019.The results of operations for our Automotive business was included within continuing operations for all the historical periods presented as the held-for-sale criterion was not met until the spin-off occurred on October 1, 2019. Effective the first quarter of fiscal year 2020, the historical results of our Automotive business will be included within discontinued operations for all the historical periods presented. Other DispositionsIn connection with our comprehensive portfolio and business review efforts, we commenced a wind-down of our Devices and Mobile Operator Services businesses during the fourth quarter of fiscal year 2018. In May 2019, we completed the sale of our Mobile Operator Services business in Brazil, and in July 2019, we completed the sale of our Mobile Operator Services business in India. The sale prices and any gain or loss were immaterial