Acquisitions (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended				0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended		12 Months Ended			1 Months Ended	12 Months Ended			0 Months Ended	12 Months Ended																								0 Months Ended
	Sep. 30, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Dec. 30, 2013	Jun. 30, 2014 Atego [Member] employees	Sep. 30, 2014 Atego [Member]	Jun. 30, 2014 ThingWorx, Inc. [Member] employees	Sep. 30, 2014 ThingWorx, Inc. [Member]	Jun. 28, 2014 ThingWorx, Inc. [Member]	Sep. 30, 2014 ThingWorx [Member]	Sep. 30, 2013 Servigistics, Enigma and NetIDEAS [Member]	Sep. 30, 2013 NetIDEAS and Enigma [Member]	Sep. 30, 2013 Servigistics [Member]	Sep. 30, 2014 Servigistics [Member] employees	Sep. 30, 2013 Servigistics [Member]	Sep. 30, 2014 2014 Acquisitions [Member]	Jul. 23, 2014 Axeda [Member] employees	Sep. 30, 2014 Axeda [Member]	Sep. 30, 2014 Purchased Software [Member]	Sep. 30, 2014 Purchased Software [Member] Atego [Member]	Sep. 30, 2014 Purchased Software [Member] ThingWorx, Inc. [Member]	Sep. 30, 2014 Purchased Software [Member] Axeda [Member]	Sep. 30, 2014 Customer Lists and Relationships [Member] Atego [Member]	Sep. 30, 2014 Customer Lists and Relationships [Member] ThingWorx, Inc. [Member]	Sep. 30, 2014 Customer Lists and Relationships [Member] Axeda [Member]	Sep. 30, 2014 Trademarks And Trade Names [Member]	Sep. 30, 2014 Trademarks And Trade Names [Member] Atego [Member]	Sep. 30, 2014 Trademarks And Trade Names [Member] ThingWorx, Inc. [Member]	Sep. 30, 2014 Trademarks And Trade Names [Member] Axeda [Member]	Sep. 30, 2014 Other Intangible Assets [Member]	Sep. 30, 2014 Other Intangible Assets [Member] Atego [Member]	Sep. 30, 2014 Other Intangible Assets [Member] ThingWorx [Member]	Sep. 30, 2014 Other Intangible Assets [Member] Axeda [Member]	Sep. 30, 2014 Segment, Software Products [Member] Atego [Member]	Sep. 30, 2014 Segment, Software Products [Member] ThingWorx [Member]	Sep. 30, 2013 Segment, Software Products [Member] Servigistics [Member]	Sep. 30, 2014 Segment, Software Products [Member] Axeda [Member]	Sep. 30, 2014 Services [Member] Atego [Member]	Sep. 30, 2014 Services [Member] ThingWorx [Member]	Sep. 30, 2013 Services [Member] Servigistics [Member]	Sep. 30, 2014 Services [Member] Axeda [Member]	Nov. 17, 2014 Subsequent Event [Member]	Dec. 27, 2013 Line of Credit [Member] ThingWorx [Member]
Revenue from acquisition		$ 9,800,000										$ 94,900,000			$ 80,000,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual		12,000,000
Deferred Tax Liabilities, Net		136,196,000	120,796,000				3,476,000		8,934,000			38,672,000					21,600,000		9,145,000
Acquisition-related cost		12,700,000	9,900,000	3,800,000
Number of employees added by acquisition															400
Business acquisition, cost of acquired entity, cash paid		323,525,000	245,843,000	220,000		46,015,000	46,106,000		111,519,000				25,000,000	220,818,000					165,900,000
Proceeds from Lines of Credit		1,386,250,000	0	230,000,000														170,000,000																									35,000,000	110,000,000
Acquisition of businesses, net cash acquired		9,575,000					3,550,000		133,000				1,000,000	1,400,000					9,575,000
Business Combination, Contingent Consideration, Liability		13,048,000			13,048,000		0			13,048,000									0
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low		16,500,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability		2,143,000
Business Acquisition, Number of Employees of Acquiree						110		40										160
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High		18,000,000
Goodwill acquired							27,256,000		102,190,000		102,190,000		14,300,000			139,833,000			130,443,000																27,256,000	102,190,000	127,033,000	126,034,000	0	0	12,800,000	4,409,000
Finite-lived Intangible Assets Acquired		59,170,000					27,750,000		32,520,000				15,200,000								8,200,000	21,000,000	19,700,000	19,400,000	8,800,000	36,600,000		150,000	2,300,000	2,800,000		0	420,000	70,000
Deferred Tax Liabilities, Intangible Assets													5,300,000
Deferred tax assets, change in valuation allowance	(124,500,000)														32,600,000
Weighted average useful lives of acquired intangible assets																				9 years	11 years	11 years	9 years	9 years	9 years	11 years	9 years	3 years	12 years	12 years	3 years		3 years	2 years
Research and Development in Process		$ 500,000