Acquisitions Acquisitions (Purchase Price Allocation) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Apr. 02, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 165,802	$ 98,411	$ 323,525
Acquired entity name: Kepware [Member]
Business Acquisition [Line Items]
Goodwill	$ 77,081	77,081
Identifiable intangible assets		34,500
Cash		590	1,313
Other assets and liabilities, net		4,729
Total allocation of purchase price consideration		116,900	103,705
Less: cash acquired		(590)	(1,313)
Total purchase price allocation, net of cash acquired		116,310	102,392
Less: contingent consideration		(16,900)	(3,800)
Payments to Acquire Businesses, Net of Cash Acquired		99,410	$ 98,592
Acquired entity name: Vuforia [Member]
Business Acquisition [Line Items]
Goodwill		23,316
Identifiable intangible assets		41,200
Cash		4,466
Other assets and liabilities, net		261
Total allocation of purchase price consideration		69,243
Less: cash acquired		(4,466)
Total purchase price allocation, net of cash acquired		64,777
Less: contingent consideration		0
Payments to Acquire Businesses, Net of Cash Acquired		$ 64,777