Accrued Expenses (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Accrued Expenses
Accrued payables	$ 6.6	$ 4.8
Accrued payroll	4.9	2.9
Accrued taxes	1.3	1.4
Accrued insurance	1.1	2.5
Accrued expenses	$ 13.9	$ 11.6