Accrued Expenses (Details) - USD ($) $ in Millions	Dec. 31, 2019	Sep. 30, 2018
Payables and Accruals [Abstract]
Direct costs of sales	$ 5.5	$ 4.4
Payroll and related costs	4.4	3.1
Accrued corporate cost expenses	1.6	3.2
Interest payable - cash	5.5	0.1
Asset retirement obligations	2.0	0.5
Acquisition consideration	2.5
Contract termination costs	0.1
Other creditors	9.6	3.0
Accrued expenses, net	$ 31.2	$ 14.3