Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Sep. 30, 2024 USD ($) Segment	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Percent of standalone selling price for subscriptions that contains software license	55.00%
Percent of standalone selling price for subscriptions that contains support	45.00%
Contract with customer, total liability	$ 26,000,000	$ 23,700,000
Lease expiration date				2037
Development costs for software	0	0	$ 0
Impairment of goodwill	0
Advertising expense	15,000,000	11,700,000	8,600,000
Cumulative translation adjustment gains (loss)	78,100,000	114,500,000
Pension benefits, before tax	15,200,000	9,600,000
Accumulated other comprehensive (income) loss, defined benefit plan, after tax	10,500,000	6,700,000
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Net Investment Hedges, Before Tax	14,800,000	6,900,000
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Net Investment Hedges, Effect Net of Tax	13,100,000	3,100,000
Proceeds From Sale Of Investments	$ 0	349,000	46,906,000
Number of operating segments | Segment	1
Number of Reportable Segments | Segment	1
Purchased Software
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible assets acquired	$ 4,100,000	$ 1,000,000	6,000,000
Matterport, Inc.
Summary Of Significant Accounting Policies [Line Items]
Aggregate realized gain			34,000,000
Matterport, Inc. | Equity Securities [Member]
Summary Of Significant Accounting Policies [Line Items]
Proceeds From Sale Of Investments			42,700,000
Debt and Equity Securities, Gain (Loss)			(34,800,000)
Original investment			$ 8,700,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Percent of standalone selling price for subscriptions	5.00%
Minimum | Software and Computer Equipment
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)	3 years
Minimum | Furniture And Fixtures
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)	3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Percent of standalone selling price for subscriptions	50.00%
Maximum | Purchased Software
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)	16 years
Maximum | Customer Lists and Relationships
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)	20 years
Maximum | Trademarks
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)	15 years
Maximum | Software and Computer Equipment
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)	5 years
Maximum | Furniture And Fixtures
Summary Of Significant Accounting Policies [Line Items]
Amortization period (in years)	12 years
Not Designated as Hedging Instrument | Foreign Exchange Forward
Summary Of Significant Accounting Policies [Line Items]
Derivative maturity	4 months
Net Investment Hedging | Designated as Hedging Instrument | Foreign Exchange Forward
Summary Of Significant Accounting Policies [Line Items]
Derivative maturity	3 months