Accounts Receivable (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Receivables [Abstract]
Trade receivables	$ 13.1	$ 17.8
Less: long-term receivable recorded in other assets	(1.8)	(2.2)
Other receivables	0.1	0.1
Allowance for doubtful accounts	(0.7)	(1.4)
Total accounts receivable, net	$ 10.7	$ 14.3