Statements Of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities:
Net income (loss)	$ 20.2	$ (10.8)	$ 21.5
Noncash items included in net income (loss):
Depreciation and amortization	147.7	147.7	159.8
Noncash equity-based compensation and employee benefits expense	20.3	22.0	21.0
Non-union pension settlement charge	10.9	7.6	0.0
Deferred income tax benefit, net	(1.1)	(13.2)	(0.4)
Gains on property disposals, net	(20.8)	(0.6)	(14.6)
Other noncash items, net	4.9	13.2	6.1
Changes in assets and liabilities, net:
Accounts receivable	16.6	(38.6)	(21.0)
Accounts payable	6.1	10.9	(1.1)
Other operating assets	5.4	14.9	10.5
Other operating liabilities	14.6	(92.4)	(78.0)
Net cash provided by operating activities	224.8	60.7	103.8
Investing Activities:
Acquisition of property and equipment	(145.4)	(103.3)	(100.6)
Proceeds from disposal of property and equipment	36.4	8.8	35.1
Proceeds from disposal of equity method investment, net	0.0	0.0	14.6
Net cash used in investing activities	(109.0)	(94.5)	(50.9)
Financing Activities:
Repayment of long-term debt	(31.9)	(79.3)	(70.7)
Debt issuance costs	0.0	(14.5)	(1.8)
Payments for tax withheld on equity-based compensation	(2.0)	(2.4)	(0.7)
Net cash used in financing activities	(33.9)	(96.2)	(73.2)
Net Increase (Decrease) In Cash and Cash Equivalents and Restricted Amounts Held in Escrow	81.9	(130.0)	(20.3)
Cash and Cash Equivalents and Restricted Amounts Held in Escrow, Beginning of Year	145.7	275.7	296.0
Cash and Cash Equivalents and Restricted Amounts Held in Escrow, End of Year	227.6	145.7	275.7
Supplemental Cash Flow Information:
Interest paid	(101.2)	(103.4)	(90.2)
Letter of credit fees paid	(7.0)	(7.0)	(8.5)
Income tax refund (payment), net	$ (5.5)	$ 1.7	$ (6.8)