Fair Value Measurements (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Dec. 31, 2016	Sep. 30, 2016
Financial assets:
Cash equivalents			$ 60,418	$ 60,139
Available-for-sale Securities			49,834	49,616
Forward contracts			4,505	260
Financial assets, fair value			114,757	110,015
Financial liabilities:
Contingent consideration related to acquisitions	$ 19,570		16,594	19,570
Forward contracts			629	3,170
Liabilities, Fair Value Disclosure, Recurring			17,223	22,740
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	19,570
Payment of contingent consideration	3,100	$ 1,300
Balance, December 31, 2016	16,594
Level 1 [Member]
Financial assets:
Cash equivalents			60,418	60,139
Forward contracts			0
Financial assets, fair value			95,017	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, December 31, 2016	0
Level 2 [Member]
Financial assets:
Cash equivalents			0	0
Available-for-sale Securities			0	0
Forward contracts			4,505	260
Financial assets, fair value			19,740	15,275
Financial liabilities:
Contingent consideration related to acquisitions	0		0	0
Forward contracts			629	3,170
Liabilities, Fair Value Disclosure, Recurring			629	3,170
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	0
Balance, December 31, 2016	0
Level 3 [Member]
Financial assets:
Cash equivalents			0	0
Forward contracts			0	0
Financial assets, fair value			0	0
Financial liabilities:
Contingent consideration related to acquisitions	19,570		16,594	19,570
Forward contracts			0	0
Liabilities, Fair Value Disclosure, Recurring			16,594	19,570
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	19,570
Change in present value of contingent consideration	74
Payment of contingent consideration	3,050
Balance, December 31, 2016	16,594
Acquired entity name: ColdLight [Member] | Level 3 [Member]
Financial liabilities:
Contingent consideration related to acquisitions	2,500		1,250	2,500
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	2,500
Change in present value of contingent consideration	0
Payment of contingent consideration	1,250
Balance, December 31, 2016	1,250
acquired entity name-Kepware [Domain] | Level 3 [Member]
Financial liabilities:
Contingent consideration related to acquisitions	17,070		15,344	17,070
Business Combination. Contingent Consideration [Roll Forward]
Balance, October 1, 2016	17,070
Change in present value of contingent consideration	74
Payment of contingent consideration	1,800
Balance, December 31, 2016	15,344
Acquired entity name: Kepware [Member]
Financial liabilities:
Contingent consideration related to acquisitions	15,300		15,300
Business Combination. Contingent Consideration [Roll Forward]
Balance, December 31, 2016	$ 15,300
Certificates of deposit | Level 2 [Member]
Financial assets:
Available-for-sale Securities			880	681
Commercial Paper [Member] | Level 2 [Member]
Financial assets:
Available-for-sale Securities			11,964	11,925
Corporate Bond Securities [Member] | Level 1 [Member]
Financial assets:
Available-for-sale Securities			34,599	34,601
US Government Agencies Debt Securities [Member] | Level 2 [Member]
Financial assets:
Available-for-sale Securities			$ 2,391	$ 2,409