Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended		30 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	$ 2,100		$ 2,100	$ 8,400
Payment of contingent consideration	8,400	$ 12,100
Business Combination, Consideration Transferred, Liabilities Incurred	7,800	11,100
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	2,100	7,862	2,100	8,400	$ 19,570
Payment of contingent consideration	8,400	12,100
Level 3 | Accrued Expenses and Other Current Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	1,100		1,100
Level 3 | Other Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	1,000		1,000
Kepware
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	0		0
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	18,000		18,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low	16,900		16,900
Payment of contingent consideration			18,000
Kepware | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	0	7,862	$ 0	$ 8,400	$ 17,070
Payment of contingent consideration	$ 8,400	$ 9,600