Goodwill and Acquired Intangible Assets (Schedule Of Movements of Goodwill by Reportable Segment) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Goodwill [Roll Forward]
Balance, beginning of period	$ 769,095	$ 610,347
Foreign currency translation and other adjustments	(16,457)	4,568
Balance, end of period	1,012,527	769,095
Software Products [Member]
Goodwill [Roll Forward]
Balance, beginning of period	720,548	585,469
Foreign currency translation and other adjustments	(16,260)	4,476
Balance, end of period	959,768	720,548
Services [Member]
Goodwill [Roll Forward]
Balance, beginning of period	48,547	24,878
Foreign currency translation and other adjustments	(197)	92
Balance, end of period	52,759	48,547
Servigistics [Member]
Goodwill [Roll Forward]
Goodwill acquired		139,833
Servigistics [Member] | Software Products [Member]
Goodwill [Roll Forward]
Goodwill acquired		127,033
Servigistics [Member] | Services [Member]
Goodwill [Roll Forward]
Goodwill acquired		12,800
NetIDEAS [Member]
Goodwill [Roll Forward]
Goodwill acquired		10,196
NetIDEAS [Member] | Software Products [Member]
Goodwill [Roll Forward]
Goodwill acquired		0
NetIDEAS [Member] | Services [Member]
Goodwill [Roll Forward]
Goodwill acquired		10,196
Enigma [Member]
Goodwill [Roll Forward]
Goodwill acquired		4,151
Enigma [Member] | Software Products [Member]
Goodwill [Roll Forward]
Goodwill acquired		3,570
Enigma [Member] | Services [Member]
Goodwill [Roll Forward]
Goodwill acquired		581
ThingWorx [Member]
Goodwill [Roll Forward]
Goodwill acquired	102,190
ThingWorx [Member] | Software Products [Member]
Goodwill [Roll Forward]
Goodwill acquired	102,190
ThingWorx [Member] | Services [Member]
Goodwill [Roll Forward]
Goodwill acquired	0
Atego [Member]
Goodwill [Roll Forward]
Goodwill acquired	27,256
Atego [Member] | Software Products [Member]
Goodwill [Roll Forward]
Goodwill acquired	27,256
Atego [Member] | Services [Member]
Goodwill [Roll Forward]
Goodwill acquired	0
Axeda [Member]
Goodwill [Roll Forward]
Goodwill acquired	130,443
Axeda [Member] | Software Products [Member]
Goodwill [Roll Forward]
Goodwill acquired	126,034
Axeda [Member] | Services [Member]
Goodwill [Roll Forward]
Goodwill acquired	$ 4,409