Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash Flows from Operating Activities:
Net income (loss)	$ 28.0	$ (22.6)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Loss on divestiture of business	14.7	0.0
Depreciation and amortization expense	82.4	75.8
Deferred income tax expense	4.5	6.9
Settlement loss and expense for pension plan	0.0	13.1
Gain on curtailment and payments in excess of expense for postretirement plan benefits	(2.0)	(6.4)
Share-based compensation expense	5.0	5.8
Loss from equity method investment	0.0	21.6
(Gain) loss on extinguishment of debt	(24.9)	9.4
Changes in working capital pertaining to operating activities (net of the effects of divestiture and acquisition):
Receivables	10.3	8.0
Inventories	24.1	20.7
Accounts payable	(3.5)	(10.4)
Accrued liabilities	6.7	(20.9)
Deferred revenue	25.5	1.1
Interest payable	(12.1)	(10.8)
Income taxes	4.4	(5.0)
Other	3.0	(3.3)
Net cash provided by operating activities	166.1	83.0
Cash Flows from Investing Activities:
Capital expenditures	(42.9)	(49.3)
Acquisition of business	0.0	(193.1)
Decrease (increase) in restricted cash	17.5	(21.5)
Divestiture of coal business	(12.8)	0.0
Other investing activities	2.1	0.0
Net cash used in investing activities	(36.1)	(263.9)
Cash Flows from Financing Activities:
Proceeds from issuance of long-term debt	0.0	210.8
Repayment of long-term debt	(60.8)	(149.8)
Proceeds from revolving credit facility	20.0	185.0
Repayment of revolving credit facility	(85.4)	0.0
Proceeds from financing obligation	16.2	0.0
Repayment of financing obligation	(0.5)	0.0
Debt issuance costs	(0.2)	(4.8)
Cash distribution to noncontrolling interests	(36.9)	(31.0)
Shares repurchased	0.0	(35.7)
Units repurchased	0.0	(10.0)
Other financing activities	(0.5)	(1.0)
Dividends paid	0.0	(18.4)
Net cash (used in) provided by financing activities	(148.1)	145.1
Net decrease in cash and cash equivalents	(18.1)	(35.8)
Cash and cash equivalents at beginning of period	123.4	139.0
Cash and cash equivalents at end of period	105.3	103.2
Supplemental Disclosure of Cash Flow Information
Interest paid	54.2	52.4
Income taxes paid, net of refunds of $6.3 million in 2016 and no refunds in 2015	$ (3.1)	$ 3.3