CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Activities:
Net income	$ 26.1	$ 56.6	$ 116.6
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	49.4	51.1	45.9
Equity compensation expense	15.1	14.3	11.8
Deferred income taxes	(17.3)	(3.6)	(20.6)
Equity in undistributed income of unconsolidated joint ventures	(1.4)	(1.8)	(4.4)
Dividends received from unconsolidated joint ventures	2.5	4.3	4.7
Gain on JV Separation Agreement transactions	(7.7)	0.0	0.0
Gain on sale of business	0.0	(0.7)	0.0
(Gain) loss on sale or disposal of property, plant and equipment	0.1	(2.6)	0.5
Impairment charges	7.9	0.0	65.1
Other non-cash charges, net	2.5	0.6	0.4
Changes in assets and liabilities:
Accounts receivable	19.0	(10.8)	(32.3)
Proceeds from insurance related to operations	4.1	25.6	1.2
Contract assets	20.2	(5.9)	(3.9)
Inventories, net	7.5	28.3	(51.6)
Other current assets	2.8	4.2	(6.3)
Accounts payable and other accrued expenses	4.0	(26.6)	(8.8)
Other, net	(7.7)	(1.6)	11.2
Net cash provided by operating activities	127.1	131.4	129.5
Investing Activities:
Capital expenditures	(56.1)	(57.0)	(116.8)
Acquisition of business, net of cash received	0.0	0.0	(3.6)
Disposition of business	0.0	1.7	0.0
Net cash from JV Separation Agreement transactions	8.1	0.0	0.0
Proceeds from the sale of marketable equity securities	1.5	0.0	0.0
Purchases of marketable equity securities	(0.5)	0.0	0.0
Proceeds from the sale of property, plant and equipment, net	1.4	5.6	0.0
Proceeds from insurance claims	0.0	1.8	7.3
Net cash used in investing activities	(45.6)	(47.9)	(113.1)
Financing Activities:
Proceeds from borrowings under revolving credit facility	0.0	0.0	100.0
Repayment of debt principal and finance lease obligations	(30.4)	(185.4)	(75.3)
Line of credit issuance costs	0.0	(1.7)	0.0
Payments of taxes related to net share settlement of equity awards	(1.4)	(3.2)	(10.8)
Proceeds from issuance of shares to employee stock purchase plan	1.5	0.0	1.0
Share repurchases	(19.8)	0.0	(25.0)
Net cash used in financing activities	(50.1)	(190.3)	(10.1)
Effect of exchange rate fluctuations on cash	(3.3)	2.6	(2.7)
Net increase (decrease) in cash and cash equivalents	28.1	(104.2)	3.6
Cash and cash equivalents at beginning of period	131.7	235.9	232.3
Cash and cash equivalents at end of period	159.8	131.7	235.9
Supplemental Disclosures:
Accrued capital additions	8.4	5.9	6.7
Cash paid during the year for:
Interest, net of amounts capitalized	1.7	10.4	9.7
Income taxes, net of refunds	$ 19.5	$ 6.9	$ 60.8