Disposition of Business (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Feb. 01, 2019	Nov. 07, 2018	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net									$ 30,959
Provision for Income Taxes, Discontinued Operations	$ 0		$ 1,014		$ (2,688)	$ 2,013
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0		6,683		99,472	15,534
Depreciation, Discontinued Operations	0		167		391	917
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0		5,849		6,569	17,909
Stock Compensation Expense, Discontinued Operations	0		1,703		7,103	5,471
Disposal Group, Including Discontinued Operation, Prepaid and Other Assets									3,443
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment									2,442
Disposal Group, Including Discontinued Operation, Goodwill									257,352
Disposal Group, Including Discontinued Operation, Intangible Assets									99,507
Disposal Group, Including Discontinued Operation, Other Assets									196
Disposal Group, Including Discontinued Operation, Assets									393,899
Disposal Group, Including Discontinued Operation, Accounts Payable									3,604
Disposal Group, Including Discontinued Operation, Accrued Liabilities									12,304
Disposal Group, Including Discontinued Operation, Deferred Revenue									107,965
Disposal Group, Including Discontinued Operation, Revenue	0		53,438		67,430	155,890
Disposal Group, Including Discontinued Operation, Consideration							$ 404,000	$ 400,000
Disposal Group, Including Discontinued Operation, Costs of Goods Sold	0		12,107		16,946	37,031
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	0		7,697		(5,587)	17,547
Disposal Group, Including Discontinued Operation, Other Liabilities									2,658
Disposal Group, Including Discontinued Operation, Liabilities									$ 126,531
Gain (Loss) on Disposition of Business	0	$ 102,400	0		102,371	0
Sales Revenue, Net [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	9,135				18,535
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	0		3,895		13,251	5,194
Other Operating Income	0		(200)		0	(38)
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		0		(386)	0
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		4,261		5,219	12,757
General and Administrative Expense
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Operating Expense	0		987		1,997	3,211
Sales and marketing
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	1,603				1,023
Disposal Group, Including Discontinued Operation, Operating Expense	0		18,392		28,433	59,122
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		$ 6,299		7,557	$ 21,066
Provision (benefit) for income taxes [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ (650)				$ 10,029
Discontinued Operations, Disposed of by Sale [Member] | Sales Revenue, Net [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification				$ 2,400
Discontinued Operations, Disposed of by Sale [Member] | Sales and marketing
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification				1,400
Discontinued Operations, Disposed of by Sale [Member] | Provision (benefit) for income taxes [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification				$ 1,600