Summary Of Significant Accounting Policies (Narrative) (Details)	1 Months Ended	12 Months Ended
	Jul. 31, 2015 USD ($)	Sep. 30, 2017 USD ($) primary_source mo	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Jan. 12, 2016 USD ($)	May 07, 2015 USD ($)	Sep. 30, 2014 USD ($)	Mar. 29, 2014 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Maximum payment terms on software purchases for credit-worthy customers (in months) | mo		24
Subscription revenue, number of primary sources | primary_source		2
Cloud services revenue percent of total revenue		5.00%	5.00%	5.00%
Cost Method Investments		$ 700,000	$ 11,600,000
Proceeds from sale of cost method investments		13,700,000
Gain on sale of cost-method investments		3,700,000
Payment of contingent consideration		12,100,000	11,500,000
Contingent consideration		8,400,000	19,570,000	$ 13,000,000
Allowance for doubtful accounts receivable		1,100,000	1,000,000	1,000,000			$ 1,600,000
Accounts receivable written-off, net of recoveries		1,500,000	300,000	800,000
Bad debt expense including general and administrative expense		1,500,000	300,000	200,000
Development costs for software		0	0	0
Capitalized software in connection with acquisition		6,000,000	71,500,000
Advertising expense		2,500,000	2,100,000	1,100,000
Cumulative translation adjustment gains (loss)		(54,600,000)	(71,200,000)
Pension benefits, before tax		24,700,000	38,700,000
Pension benefits net of tax		17,600,000	27,400,000
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Before Tax		1,800,000
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax		1,500,000	1,400,000
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		(100,000)	(100,000)
Unamortized Debt Issuance Expense		5,719,000	6,524,000
Deferred Tax Assets, Other		$ 15,849,000	14,778,000
Minimum [Member] | Computer Hardware And Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)		3 years
Minimum [Member] | Furniture And Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)		3 years
Maximum [Member] | Purchased Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)		11 years
Maximum [Member] | Customer Lists [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)		12 years
Maximum [Member] | Trademarks And Trade Names [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)		12 years
Maximum [Member] | Computer Hardware And Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)		5 years
Maximum [Member] | Furniture And Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)		8 years
Foreign Exchange Forward [Member]
Summary Of Significant Accounting Policies [Line Items]
Derivative maturity (in months)		3 months
Kepware [Member]
Summary Of Significant Accounting Policies [Line Items]
Payment of contingent consideration		$ 9,600,000	0
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High					$ 18,000,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low					$ 16,900,000
Contingent consideration		8,400,000	17,070,000	0
ColdLight [Member]
Summary Of Significant Accounting Policies [Line Items]
Payment of contingent consideration		2,500,000	2,500,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High						$ 5,000,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low						$ 3,800,000
Contingent consideration		0	2,500,000	4,000,000
ThingWorx [Member]
Summary Of Significant Accounting Policies [Line Items]
Payment of contingent consideration	$ 9,000,000	0	9,000,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High								$ 18,000,000
Contingent consideration		$ 0	0	9,000,000
Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Summary Of Significant Accounting Policies [Line Items]
Derivative, Remaining Maturity		15 months
Accounting Standards Update 2015-03 [Member]
Summary Of Significant Accounting Policies [Line Items]
Unamortized Debt Issuance Expense			6,500,000
Accounting Standards Update 2016-16 [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred Tax Assets, Other		$ 77,000,000
Accounting Standards Update 2016-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated forfeiture adjustment		1,000,000
Cash Provided For (Used In) Financing Activities [Member]
Summary Of Significant Accounting Policies [Line Items]
Payment of contingent consideration		$ 11,000,000	$ 10,600,000	$ 4,300,000