Commitments (Details) $ in Millions	12 Months Ended
	Sep. 30, 2019 USD ($) lb / h	Sep. 30, 2018 USD ($)
Purchase Of Steam Under Steam Contract | lb / h	475,000
Expenses Related To Steam Contract	$ 5.7	$ 4.2
Operating Leases, Future Minimum Payments Due, Next Twelve Months	3.2
Operating Leases, Future Minimum Payments, Due in Two Years	3.1
Operating Leases, Future Minimum Payments, Due in Three Years	2.6
Operating Leases, Future Minimum Payments, Due in Four Years	1.2
Operating Leases, Rent Expense, Net	4.0	4.7
Unrelated Party [Member]
Operating Leases, Rent Expense, Net	$ 0.2	$ 0.6