Discontinued Operations and Disposal Groups (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale of discontinued operations, net of benefit for income taxes of $1.0, $—, $1.4, and $—	$ (4.6)	$ 0.0	$ (5.7)	$ 0.0
Discontinued Operation, Tax Effect of Discontinued Operation	(0.5)	2.1	(2.5)	4.4
(Income) loss from discontinued operations, net of income taxes			(10.3)	13.9
Proceeds from Sale of Discontinued Operations, Net of Cash Divested
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash Provided by (Used in) Investing Activities, Discontinued Operations			2.7	0.0
Sale of Highway Products
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	(4.3)		(5.8)
Loss on sale of discontinued operations, net of benefit for income taxes of $1.0, $—, $1.4, and $—	(3.3)		(4.4)
Disposal Group, Including Discontinued Operation, Revenue	0.0	78.2	0.0	146.3
Disposal Group, Including Discontinued Operation, Costs of Goods Sold	0.0	55.3	0.0	104.8
Disposal Group, Including Discontinued Operation, General and Administrative Expense	3.9	13.2	12.8	23.2
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	(3.9)	9.7	(12.8)	18.3
Discontinued Operation, Tax Effect of Discontinued Operation	(0.5)	2.1	(2.5)	4.0
(Income) loss from discontinued operations, net of income taxes	(3.4)	$ 7.6	(10.3)	14.3
Sale of Highway Products \| Proceeds from Sale of Discontinued Operations, Net of Cash Divested
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash Provided by (Used in) Investing Activities, Discontinued Operations	$ 2.7		$ 2.7		$ (364.7)
Spin-off of Arcosa
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Income) loss from discontinued operations, net of income taxes				$ (0.4)

Amount of cash inflow (outflow) of investing activities of discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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