Goodwill and Acquired Intangible Assets (Schedule Of Movements of Goodwill by Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Sep. 30, 2016	Jul. 02, 2016	Apr. 02, 2016	Jan. 02, 2016	Sep. 30, 2017	Sep. 30, 2016
Goodwill [Roll Forward]
Balance, beginning of period	$ 1,169,660			$ 1,069,041	$ 1,169,813	$ 1,069,041
Goodwill acquired					2,847
Foreign currency translation and other adjustments	153	$ 222			10,112
Balance, end of period	1,169,813	1,169,660			1,182,772	1,169,813
Software Products [Member]
Goodwill [Roll Forward]
Balance, beginning of period	1,117,038			1,016,413		1,016,413
Foreign currency translation and other adjustments		228
Balance, end of period		1,117,038
Services [Member]
Goodwill [Roll Forward]
Balance, beginning of period	52,622			52,628		52,628
Foreign currency translation and other adjustments		(6)
Balance, end of period		52,622
Solutions Group [Member]
Goodwill [Roll Forward]
Balance, beginning of period	1,050,013				1,050,150
Goodwill acquired					2,847
Foreign currency translation and other adjustments	137				9,077
Balance, end of period	1,050,150	1,050,013			1,062,074	1,050,150
IoT Group [Member]
Goodwill [Roll Forward]
Balance, beginning of period	90,053				90,065
Goodwill acquired					0
Foreign currency translation and other adjustments	12				778
Balance, end of period	90,065	90,053			90,843	90,065
Professional Services [Member]
Goodwill [Roll Forward]
Balance, beginning of period	29,594				29,598
Goodwill acquired					0
Foreign currency translation and other adjustments	4				257
Balance, end of period	$ 29,598	$ 29,594			$ 29,855	29,598
Vuforia Acquisition [Member]
Goodwill [Roll Forward]
Goodwill acquired				23,316
Vuforia Acquisition [Member] | Software Products [Member]
Goodwill [Roll Forward]
Goodwill acquired				23,316
Vuforia Acquisition [Member] | Services [Member]
Goodwill [Roll Forward]
Goodwill acquired				$ 0
Kepware [Member]
Goodwill [Roll Forward]
Goodwill acquired			$ 77,081			$ 77,081
Kepware [Member] | Software Products [Member]
Goodwill [Roll Forward]
Goodwill acquired			77,081
Kepware [Member] | Services [Member]
Goodwill [Roll Forward]
Goodwill acquired			$ 0