STATEMENTS OF CONSOLIDATED CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net income (loss)	$ 34.2	$ (5.7)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation of property, plant and equipment	49.9	48.1
Amortization of definite-lived intangible assets	2.8	6.5
Amortization of debt premium and debt issuance costs	1.0	1.1
Deferred income taxes	6.6	(4.1)
Non-cash equity compensation	7.9	7.8
Non-cash asset impairment charge		3.2
(Gain) loss on disposition of property, plant and equipment	(14.2)	2.1
Changes in operating assets and liabilities:
Trade and other receivables	(17.8)	(13.5)
Contract assets	2.3	(30.7)
Inventories	27.5	(64.0)
Prepaid expenses and other current assets	(4.7)	(5.0)
Accounts payable	(56.0)	61.8
Accrued liabilities	2.3	1.9
Long-term assets and liabilities, net	6.0	(2.5)
Net cash provided by operating activities	47.8	7.0
Cash flows from investing activities:
Capital expenditures	(82.6)	(45.5)
Purchase of equity securities	(0.3)	(0.3)
Proceeds from disposition of property, plant and equipment	15.2	1.0
Net cash used in investing activities	(67.7)	(44.8)
Cash flows from financing activities:
Borrowings under the Revolving Credit Facility	210.0
Repayment of borrowings under the Revolving Credit Facility	(195.0)
Cash paid for debt issuance costs		(1.8)
Repayment of finance lease	(1.2)	(1.0)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares	(1.7)	(1.9)
Cash dividends and dividend equivalents paid	(25.1)	(25.1)
Net cash used in financing activities	(13.0)	(29.8)
Net decrease in cash, cash equivalents and restricted cash during the period	(32.9)	(67.6)
Cash, cash equivalents and restricted cash at beginning of period	71.3	317.0
Cash, cash equivalents and restricted cash at end of period	$ 38.4	$ 249.4