Acquisitions (Narrative) (Details) $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 02, 2012 USD ($) employees	Jul. 31, 2015 USD ($)	Mar. 29, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	May. 07, 2015 USD ($)
Acquisition-related cost				$ 8,900	$ 12,700	$ 9,900
Business acquisition, cost of acquired entity, cash paid				98,411	323,525	245,843
Proceeds from Lines of Credit				185,000	1,386,250	0
Payments to Business Combination Contingent Consideration Financing Activities				4,323	0	0
Contingent consideration				13,000	15,191
Atego [Member]
Goodwill acquired					27,256
ThingWorx, Inc. [Member]
Business acquisition, cost of acquired entity, cash paid			$ 111,519
Acquisition of businesses, net cash acquired			$ 133
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High				18,000
acquired entity name-ThingWorx [Member]
Change in fair value of contingent consideration				2,809	2,143
payment of contingent consideration		$ 9,000
Contingent consideration				9,000	15,191	0
ThingWorx [Member]
Goodwill acquired					102,190
Servigistics, Enigma and NetIDEAS [Member]
Deferred Tax Liabilities, Net						38,700
Servigistics [Member]
Revenue from acquisition	$ 80,000
Number of employees added by acquisition | employees	400
Business acquisition, cost of acquired entity, cash paid	$ 220,818
Acquisition of businesses, net cash acquired	$ 1,400
Deferred tax assets, change in valuation allowance						32,600
2014 Acquisitions [Member]
Deferred Tax Liabilities, Net					21,600
Acquired entity name: ColdLight [Member]
Business acquisition, cost of acquired entity, cash paid				98,592
Acquisition of businesses, net cash acquired				1,313
Contingent consideration				4,000			$ 3,800
Change in fair value of contingent consideration				200	0
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High							$ 5,000
payment of contingent consideration				0
Goodwill acquired				85,288
Finite-lived Intangible Assets Acquired				17,620
Contingent consideration				$ 4,000	0	$ 0
Axeda [Member]
Goodwill acquired					130,443
Axeda and Atego Acquisitions [Member]
Deferred Tax Liabilities, Net					12,621
Business acquisition, cost of acquired entity, cash paid					212,006
Acquisition of businesses, net cash acquired					13,125
Goodwill acquired					157,699
Finite-lived Intangible Assets Acquired					86,920
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
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
Weighted average useful lives of acquired intangible assets				9 years
Trademarks and Trade Names [Member] | Acquired entity name: ColdLight [Member]
Finite-lived Intangible Assets Acquired				$ 500
Weighted average useful lives of acquired intangible assets				7 years
Segment, Software Products [Member] | Atego [Member]
Goodwill acquired					27,256
Segment, Software Products [Member] | ThingWorx [Member]
Goodwill acquired					102,190
Segment, Software Products [Member] | Acquired entity name: ColdLight [Member]
Goodwill acquired				$ 85,288
Segment, Software Products [Member] | Axeda [Member]
Goodwill acquired					126,034
Services [Member] | Atego [Member]
Goodwill acquired					0
Services [Member] | ThingWorx [Member]
Goodwill acquired					0
Services [Member] | Acquired entity name: ColdLight [Member]
Goodwill acquired				$ 0
Services [Member] | Axeda [Member]
Goodwill acquired					$ 4,409
contingent consideration payment included in financing activities of cash flow [Member] | acquired entity name-ThingWorx [Member]
Payments to Business Combination Contingent Consideration Financing Activities		4,323
contingent consideration payment included in operating activities of cash flow [Member] | acquired entity name-ThingWorx [Member]
Payments to Business Combination Contingent Consideration		$ 4,700