Derivatives (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2019
Cash Flow Hedging [Member] | Other Assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Fair Value, Net					$ 900,000
Cash Flow Hedging [Member] | Other Current Liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Fair Value, Net	$ (45,200,000)		$ (45,200,000)		(7,700,000)
Currency Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount					6,700,000
Derivative, Fair Value, Net					200,000
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	76,000,000.0		76,000,000.0		76,700,000
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	(100,000)		(100,000)	$ 500,000
Derivative, Gain on Derivative	(600,000)		(1,100,000)
Derivative, Loss on Derivative				300,000
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	750,000,000.0		750,000,000.0		750,000,000.0
Derivative, Fair Value, Net					(6,800,000)
Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	198,300,000		198,300,000
Net Investment Hedging [Member] | Other Assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Fair Value, Net	22,300,000		22,300,000		$ 16,900,000
Net Investment Hedging [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	$ 1,300,000	$ 1,200,000	$ 2,600,000	$ (100,000)