Note 2. Acquisitions and Discontinued Operations - Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on sale of discontinued operations, net of provision (benefit) for income taxes of $(1.4), $51.9, and $—	$ 0.0	$ 0.0	$ (4.6)	$ (1.1)	$ 131.4	$ 0.0	$ 0.0	$ 0.0	$ (5.7)	$ 131.4	$ 0.0
Discontinued Operation, Tax Effect of Discontinued Operation									(1.1)	3.5	5.5
Income (loss) from discontinued operations, net of provision (benefit) for income taxes of $(1.1), $3.5, and $5.5	$ (6.6)	$ (3.4)	$ (3.4)	$ (6.9)	$ (13.2)	$ 10.4	$ 7.6	$ 6.3	(20.3)	11.1	24.3
Amounts reclassified to discontinued operations, net of tax									1.3	0.0	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									(5.8)
Gain (loss) on sale of discontinued operations, net of provision (benefit) for income taxes of $(1.4), $51.9, and $—									(4.4)
Disposal Group, Including Discontinued Operation, Revenue									0.0	296.5	249.7
Disposal Group, Including Discontinued Operation, Costs of Goods Sold									0.0	216.6	178.7
Disposal Group, Including Discontinued Operation, General and Administrative Expense									21.4	65.3	41.2
Disposal Group, Including Discontinued Operations, Restructuring Activities									0.0	0.0	0.1
Disposal Group, Including Discontinued Operation, Other Income									0.0	0.0	(0.3)
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax									(21.4)	14.6	30.0
Discontinued Operation, Tax Effect of Discontinued Operation									(1.1)	2.7	5.6
Income (loss) from discontinued operations, net of provision (benefit) for income taxes of $(1.1), $3.5, and $5.5									(20.3)	11.9	24.4
Sale of Highway Products | Proceeds from (Payments to) related to the Sale of Discontinued Operations, Net of Cash Divested
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash used in investing activities – discontinued operations									(2.7)
Proceeds (payments) related to sale of discontinued operations									$ (2.7)	364.7	0.0
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 Tax, Including Portion Attributable to Noncontrolling Interest										$ 0.8	$ 0.1