Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Trade accounts payable	$ 210.4	$ 157.7
Employee-related expenses	33.6	28.1
Accrued vacation	21.9	21.8
Miscellaneous accrued expenses	94.4	113.6
Total	$ 360.3	$ 321.2