Acquisitions (Narrative) (Details) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Apr. 30, 2016 USD ($)	Jul. 31, 2015 USD ($)	Apr. 02, 2016 USD ($)	Mar. 29, 2014 USD ($)	Sep. 30, 2016 USD ($) employee	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jan. 12, 2016 USD ($)	Nov. 03, 2015 USD ($)	May 07, 2015 USD ($)
Acquisition-related cost					$ 3,500	$ 8,900	$ 12,700
Payments to Acquire Businesses, Net of Cash Acquired					165,802	98,411	323,525
Payment of contingent consideration					11,500	9,000
Payments to Business Combination Contingent Consideration Financing Activities					10,621	4,323	0
Credit facility, borrowings outstanding					758,125	618,125
Revenue, Net					1,140,533	1,255,242	1,356,967
Costs and Expenses					851,882	878,892	786,708
ThingWorx, Inc. [Member]
Payments to Acquire Businesses, Net of Cash Acquired				$ 111,500
Acquisition of businesses, net cash acquired				100
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High				$ 18,000
Payment of contingent consideration	$ 9,000	$ 9,000
Payments to Business Combination Contingent Consideration Financing Activities	8,700	4,300
Payments to Business Combination Contingent Consideration	$ 300	$ 4,700
2014 Acquisitions [Member]
Deferred Tax Liabilities, Net							21,600
Acquired entity name: ColdLight [Member]
Contingent consideration					2,500					$ 3,800
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High										$ 5,000
Payment of contingent consideration					2,500	0
Goodwill acquired						85,288
Finite-lived Intangible Assets Acquired						17,620
Payments to Business Combination Contingent Consideration Financing Activities					1,900
Payments to Business Combination Contingent Consideration					600
Axeda and Atego Acquisitions [Member]
Deferred Tax Liabilities, Net							12,600
Payments to Acquire Businesses, Net of Cash Acquired							212,000
Acquisition of businesses, net cash acquired							13,100
Goodwill acquired							157,700
Finite-lived Intangible Assets Acquired							$ 86,900
Acquired entity name: Kepware [Member]
Payments to Acquire Businesses, Net of Cash Acquired					99,410	98,592
Acquisition of businesses, net cash acquired					590	1,313
Contingent consideration					17,100			$ 16,900
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High								18,000
Estimated contingent consideration payment in 2017								9,600
Payment of contingent consideration					0	0
Goodwill acquired			$ 77,081		77,081
Finite-lived Intangible Assets Acquired					34,500
Business acquisition, acquired net assets excluding goodwill, intangible assets and cash					4,729
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, Low					16,900	3,800
Revenue, Net					16,000
Costs and Expenses					15,000
Acquired entity name: Vuforia [Member]
Payments to Acquire Businesses, Net of Cash Acquired					64,777
Acquisition of businesses, net cash acquired					4,466
Goodwill acquired					23,316
Finite-lived Intangible Assets Acquired					41,200
Business acquisition, acquired net assets excluding goodwill, intangible assets and cash					$ 261
Weighted average useful lives of acquired intangible assets					6 years
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, Low					$ 0
Number of employees in acquired entity | employee					80
Purchased Software [Member]
Weighted average useful lives of acquired intangible assets					9 years
Purchased Software [Member] | Acquired entity name: ColdLight [Member]
Finite-lived Intangible Assets Acquired						13,600
Purchased Software [Member] | Acquired entity name: Kepware [Member]
Finite-lived Intangible Assets Acquired					$ 28,700
Weighted average useful lives of acquired intangible assets					10 years
Customer Lists [Member]
Weighted average useful lives of acquired intangible assets					10 years
Customer Lists [Member] | Acquired entity name: ColdLight [Member]
Finite-lived Intangible Assets Acquired						3,500
Customer Lists [Member] | Acquired entity name: Kepware [Member]
Finite-lived Intangible Assets Acquired					$ 5,200
Weighted average useful lives of acquired intangible assets					10 years
Trademarks and Trade Names [Member] | Acquired entity name: ColdLight [Member]
Finite-lived Intangible Assets Acquired						500
Trademarks and Trade Names [Member] | Acquired entity name: Kepware [Member]
Finite-lived Intangible Assets Acquired					$ 600
Weighted average useful lives of acquired intangible assets					6 years
Line of Credit [Member]
Credit facility, borrowings outstanding					$ 258,125	$ 193,125
Line of Credit [Member] | Acquired entity name: Kepware [Member]
Credit facility, borrowings outstanding								$ 100,000
Line of Credit [Member] | Acquired entity name: Vuforia [Member]
Credit facility, borrowings outstanding									$ 50,000