Revenue from Contracts with Customers Capitalized Commission Costs (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018
Capitalized Contract Cost [Abstract]
Capitalized Contract Cost, Net	$ 31,700,000		$ 31,700,000		$ 27,100,000
Capitalized Contract Cost, Amortization Period	10 years		10 years
Capitalized Contract Cost, Amortization	$ 1,300,000	$ 1,100,000	$ 3,700,000	$ 3,300,000
Capitalized Contract Cost, Impairment Loss	$ 0	$ 0	$ 0	$ 0