Note 2. Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
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									$ 183.3
Gain on sale of discontinued operations, net of provision for income taxes of $51.9, $—, and $—	$ 131.4	$ 0.0	$ 0.0	$ 0.0					131.4	$ 0.0	$ 0.0
Disposal Group, Including Discontinued Operations, Transaction Costs									14.7
Discontinued Operation, Tax Effect of Discontinued Operation									3.5	5.5	1.7
Income from discontinued operations, net of provision for income taxes of $3.5, $5.5, and $1.7	(13.2)	$ 10.4	$ 7.6	$ 6.3	$ 6.6	$ 6.9	$ 6.8	$ 4.0	11.1	24.3	13.7
Assets of discontinued operations	0.0				178.5				0.0	178.5
Liabilities of discontinued operations	0.0				18.5				0.0	18.5
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]
Net cash used in investing activities – discontinued operations									364.7	0.0	0.0
Missouri Class Action | Highway Products Litigation [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 23.9								23.9
Sale of Highway Products
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue									296.5	249.7	252.7
Disposal Group, Including Discontinued Operation, Costs of Goods Sold									216.6	178.7	181.6
Disposal Group, Including Discontinued Operation, General and Administrative Expense									65.3	41.2	51.5
Disposal Group, Including Discontinued Operations, Restructuring Activities									0.0	0.1	0.1
Disposal Group, Including Discontinued Operation, Other Income									0.0	(0.3)	0.0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax									14.6	30.0	19.5
Discontinued Operation, Tax Effect of Discontinued Operation									2.7	5.6	2.7
Income from discontinued operations, net of provision for income taxes of $3.5, $5.5, and $1.7									11.9	24.4	16.8
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net					34.6					34.6
Disposal Group, Including Discontinued Operation, Inventory					36.0					36.0
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment					34.6					34.6
Disposal Group, Including Discontinued Operation, Goodwill					61.6					61.6
Disposal Group, Including Discontinued Operation, Other Assets					11.7					11.7
Assets of discontinued operations					178.5					178.5
Disposal Group, Including Discontinued Operation, Accounts Payable					10.3					10.3
Disposal Group, Including Discontinued Operation, Accrued Liabilities					4.7					4.7
Disposal Group, Including Discontinued Operation, Other Liabilities					3.5					3.5
Liabilities of discontinued operations					$ 18.5					18.5
Spin-Off of Arcosa
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue									0.0	0.0	0.0
Disposal Group, Including Discontinued Operation, Costs of Goods Sold									0.0	0.0	0.0
Disposal Group, Including Discontinued Operation, General and Administrative Expense									0.0	0.2	4.1
Disposal Group, Including Discontinued Operation, Other Income									0.0	0.0	0.0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax									0.0	(0.2)	(4.1)
Discontinued Operation, Tax Effect of Discontinued Operation									0.8	(0.1)	(1.0)
Income from discontinued operations, net of provision for income taxes of $3.5, $5.5, and $1.7									$ (0.8)	$ (0.1)	$ (3.1)