Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental disclosures of cash flow information:
Cash paid for interest	$ 218.9	$ 186.3	$ 165.9
Cash paid for income taxes	4.0	2.2	3.3
Other Noncash Investing and Financing Items [Abstract]
Non-cash accrual of property and equipment	(6.5)	6.8	(22.7)
Discounted secured term loan receivable from contract restructuring	$ 0.0	$ 47.7	$ 0.0