Fair Value Measurements (Details) - USD ($) $ in Thousands	6 Months Ended
	Apr. 01, 2017	Apr. 02, 2016	Apr. 01, 2017	Sep. 30, 2016
Financial assets:
Cash equivalents			$ 62,889	$ 60,139
Available-for-sale Securities			48,191	49,616
Forward contracts			1,607	260
Financial assets, fair value			112,687	110,015
Financial liabilities:
Contingent consideration related to acquisitions	$ 19,570		16,668	19,570
Forward contracts			2,762	3,170
Liabilities, Fair Value Disclosure, Recurring			19,430	22,740
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	19,570
Addition to contingent consideration		$ 16,900
Payment of contingent consideration	(3,100)	(1,300)
Balance, April 1, 2017	16,668
Level 1 [Member]
Financial assets:
Cash equivalents			62,889	60,139
Financial assets, fair value			100,506	94,740
Financial liabilities:
Contingent consideration related to acquisitions	0		0
Forward contracts			0	0
Liabilities, Fair Value Disclosure, Recurring			0	0
Business Combination. Contingent Consideration [Roll Forward]
Balance, April 1, 2017	0
Level 2 [Member]
Financial assets:
Forward contracts			1,607	260
Financial assets, fair value			12,181	15,275
Financial liabilities:
Contingent consideration related to acquisitions	0		0	0
Forward contracts			2,762	3,170
Liabilities, Fair Value Disclosure, Recurring			2,762	3,170
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	0
Balance, April 1, 2017	0
Level 3 [Member]
Financial liabilities:
Contingent consideration related to acquisitions	19,570	13,000	16,668	19,570
Forward contracts			0	0
Liabilities, Fair Value Disclosure, Recurring			16,668	19,570
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	19,570	13,000
Change in present value of contingent consideration	148	540
Payment of contingent consideration	(3,050)	(1,250)
Balance, April 1, 2017	16,668	29,190
ThingWorx | Level 3 [Member]
Financial liabilities:
Contingent consideration related to acquisitions		9,000
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016		9,000
Addition to contingent consideration		0
Change in present value of contingent consideration		0
Payment of contingent consideration		0
Balance, April 1, 2017		9,000
ColdLight | Level 3 [Member]
Financial liabilities:
Contingent consideration related to acquisitions	2,500	4,000	1,250	2,500
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	2,500	4,000
Addition to contingent consideration		0
Change in present value of contingent consideration	0	540
Payment of contingent consideration	(1,250)	(1,250)
Balance, April 1, 2017	1,250	3,290
Kepware
Financial liabilities:
Contingent consideration related to acquisitions	15,400		15,400
Business Combination. Contingent Consideration [Roll Forward]
Balance, April 1, 2017	15,400
Kepware | Level 3 [Member]
Financial liabilities:
Contingent consideration related to acquisitions	17,070	0	15,418	17,070
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	17,070	0
Addition to contingent consideration		16,900
Change in present value of contingent consideration	148	0
Payment of contingent consideration	(1,800)	0
Balance, April 1, 2017	$ 15,418	$ 16,900
Certificates of deposit
Financial assets:
Available-for-sale Securities			682	681
Certificates of deposit | Level 2 [Member]
Financial assets:
Available-for-sale Securities			682	681
Commercial paper
Financial assets:
Available-for-sale Securities			7,490	11,925
Commercial paper | Level 2 [Member]
Financial assets:
Available-for-sale Securities			7,490	11,925
Corporate notes/bonds
Financial assets:
Available-for-sale Securities			37,617	34,601
Corporate notes/bonds | Level 1 [Member]
Financial assets:
Available-for-sale Securities			37,617	34,601
U.S. government agency securities
Financial assets:
Available-for-sale Securities			2,402	2,409
U.S. government agency securities | Level 2 [Member]
Financial assets:
Available-for-sale Securities			$ 2,402	$ 2,409