Arcosa (ACA) 10-K 27 Feb 20 2019 FY Annual report Financial data

Cover Page and DEI

Cover Page and DEI - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Jan. 15, 2020	Jun. 30, 2019
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-38494
Entity Registrant Name	Arcosa, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-5339416
Entity Address, Address Line One	500 N. Akard Street, Suite 400
Entity Address, City or Town	Dallas,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75201
City Area Code	972
Local Phone Number	942-6500
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 1,820.8
Entity Common Stock, Shares Outstanding		48,279,180
Title of 12(b) Security	Common Stock ($0.01 par value)
Trading Symbol	ACA
Security Exchange Name	NYSE
Documents Incorporated by Reference	The information required by Part III of this report, to the extent not set forth herein, is incorporated by reference from the registrant's definitive 2020 Proxy Statement.
Entity Central Index Key	0001739445
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31

Consolidated and Combined State

Consolidated and Combined Statements of Operations - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenues		$ 1,736.9	$ 1,460.4	$ 1,462.4
Operating costs:
Cost of revenues		1,404.5	1,188.4	1,167.7
Selling, general, and administrative expenses		179.5	153.9	163
Impairment charge		0	23.2	0
Total operating costs		1,584	1,365.5	1,330.7
Total operating profit		152.9	94.9	131.7
Interest expense		6.8	0.9	0
Other, net (income) expense		(0.7)	(1)	1.6
Total other (income) expense		6.1	(0.1)	1.6
Income before income taxes		146.8	95	130.1
Provision (benefit) for income taxes:
Current		16.2	(3.1)	30.1
Deferred		17.3	22.4	10.3
Total provision for income taxes		33.5	19.3	40.4
Net income		$ 113.3	$ 75.7	$ 89.7
Net income per common share:
Basic (in dollars per share)		$ 2.34	$ 1.55	$ 1.84
Diluted (in dollars per share)		$ 2.32	$ 1.54	$ 1.84
Weighted average number of shares outstanding(1):
Basic (in shares)	[1]	47.9	48.8	48.8
Diluted (in shares)	[1]	48.4	48.9	48.8
Dividends declared per common share (in dollars per share)		$ 0.20	$ 0.05	$ 0
[1]	For periods prior to the Separation, the denominator for basic and diluted net income per common share was calculated using the 48.8 million shares of common stock outstanding immediately following the Separation.

Consolidated and Combined Sta_2

Consolidated and Combined Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 113.3	$ 75.7	$ 89.7
Derivative financial instruments:
Unrealized losses arising during the period, net of tax expense (benefit) of ($0.7), ($0.3), and $0.0	(2.8)	(0.9)	0
Reclassification adjustments for losses included in net income, net of tax expense (benefit) of ($0.1), $0.0, and $0.0	0.3	0	0
Currency translation adjustment:
Unrealized gains (losses) arising during the period, net of tax expense (benefit) of $0.0, ($0.3), and $0.0	0.5	0	(1.4)
Reclassification adjustments for losses included in net income, net of tax expense (benefit) of $0.0, $0.0, and $0.0	0	3	0
Total other comprehensive income (loss)	(2)	2.1	(1.4)
Comprehensive income	$ 111.3	$ 77.8	$ 88.3

Consolidated and Combined Sta_3

Consolidated and Combined Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Unrealized gains (losses) arising during the period, tax expense (benefit)	$ (0.7)	$ (0.3)	$ 0
Reclassification adjustments for losses included in net income, tax benefit	(0.1)	0	0
Unrealized gains (losses) arising during the period, tax expense (benefit)	0	(0.3)	0
Reclassification adjustments for losses included in net income, tax expense (benefit)	$ 0	$ 0	$ 0

Consolidated and Combined Balan

Consolidated and Combined Balance Sheets - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 240.4	$ 99.4
Receivables, net of allowance for doubtful accounts of $2.3 and $8.7	200	291.4
Inventories:
Raw materials and supplies	134.8	128.4
Work in process	41.7	33.3
Finished goods	106.8	90.8
Total inventory	283.3	252.5
Other	33.5	24.1
Total current assets	757.2	667.4
Property, plant, and equipment, net	816.2	803
Goodwill	621.9	615.2
Deferred income taxes	14.3	6.9
Other assets	92.9	79.7
Assets	2,302.5	2,172.2
Liabilities, Current [Abstract]
Accounts payable	90	86.2
Accrued liabilities	119.4	99.9
Advance billings	70.9	21.6
Current portion of long-term debt	3.7	1.8
Total current liabilities	284	209.5
Debt	103.6	183.7
Deferred income taxes	66.4	58.3
Other liabilities	58.1	36.2
Total liabilities	512.1	487.7
Stockholders’ equity:
Common stock, $0.01 par value – 200.0 shares authorized at December 31, 2019; 200.0 at December 31, 2018; 48.3 shares issued and outstanding at December 31, 2019; 48.8 at December 31, 2018	0.5	0.5
Capital in excess of par value	1,686.7	1,685.7
Retained earnings	122.9	19.5
Accumulated other comprehensive loss	(19.7)	(17.7)
Treasury stock – 0.0 shares at December 31, 2019; 0.1 at December 31, 2018	0	(3.5)
Total stockholders' equity	1,790.4	1,684.5
Total liabilities and stockholders' equity	$ 2,302.5	$ 2,172.2

Consolidated and Combined Bal_2

Consolidated and Combined Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Receivables, allowance for doubtful accounts	$ 2.3	$ 8.7
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	48,300,000	48,800,000
Common stock, shares outstanding	48,300,000	48,800,000
Treasury stock, shares	0	100,000

Consolidated and Combined Sta_4

Consolidated and Combined Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net income	$ 113.3	$ 75.7	$ 89.7
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization	85.8	67.6	65.7
Impairment charge	0	23.2	0
Stock-based compensation expense	14.6	9.9	9
Provision for deferred income taxes	17.3	22.4	10.3
Gain on disposition of property and other assets	(4)	(1.1)	(1.4)
(Increase) decrease in other assets	(0.9)	6.4	(3.3)
Increase (decrease) in other liabilities	4.2	(1.7)	(7.6)
Other	(4.1)	(3.1)	0.1
Changes in current assets and liabilities:
(Increase) decrease in receivables	99	(80.9)	(26.4)
(Increase) decrease in inventories	(22.7)	(29.9)	24.3
(Increase) decrease in other current assets	(11.6)	(10.8)	(0.6)
Increase (decrease) in accounts payable	3.5	20.6	7.1
Increase (decrease) in advance billings	49.3	7.7	(9.1)
Increase (decrease) in accrued liabilities	15.1	12.5	4.2
Net cash provided by operating activities	358.8	118.5	162
Investing activities:
Proceeds from disposition of property and other assets	8.9	10.2	3.5
Capital expenditures	(85.4)	(44.8)	(82.4)
Acquisitions, net of cash acquired	(32.9)	(333.2)	(47.5)
Proceeds from divestitures	0	3.3	0
Net cash required by investing activities	(109.4)	(364.5)	(126.4)
Financing activities:
Payments to retire debt	(81.2)	(0.3)	(0.1)
Proceeds from issuance of debt	0	180	0.6
Shares repurchased	(11)	(3)	0
Dividends paid to common shareholders	(9.9)	0	0
Purchase of shares to satisfy employee tax on vested stock	(4.4)	(0.5)	0
Capital contribution from Former Parent	0	200	0
Net transfers to Former Parent and affiliates	0	(34.5)	(43)
Other	(1.9)	(3.1)	(0.3)
Net cash provided by (required by) financing activities	(108.4)	338.6	(42.8)
Net increase (decrease) in cash and cash equivalents	141	92.6	(7.2)
Cash and cash equivalents at beginning of period	99.4	6.8	14
Cash and cash equivalents at end of period	$ 240.4	$ 99.4	$ 6.8

Supplemental Cash Flow Informat

Supplemental Cash Flow Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Cash Flows [Abstract]
Income tax payments made, net	$ 18.8	$ 0.6	$ 0
Stock issued for acquisition (value)			$ 14.7

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Former Parent's Net Investment	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning balance at Dec. 31, 2016	$ 1,341.8	$ 1,360.2	$ 0	$ 0	$ 0	$ (18.4)	$ 0
Beginning balance, shares at Dec. 31, 2016			0				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	89.7	89.7
Other comprehensive loss	(1.4)					(1.4)
Capital contribution from Former Parent	0
Net transfers from Former Parent and affiliates	(31.2)	(31.2)
Restricted shares, net	9	9
Ending balance at Dec. 31, 2017	1,407.9	1,427.7	$ 0	0	0	(19.8)	$ 0
Ending balance, shares at Dec. 31, 2017			0				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adopting new accounting standards (see Note 1)	(4)	(4)
Net income	75.7	53.8			21.9
Cash dividends on common stock	(2.4)				(2.4)
Other comprehensive loss	2.1					2.1
Capital contribution from Former Parent	200	200
Net transfers from Former Parent and affiliates	(1.2)	(1.2)
Restricted shares, net		(1,684.6)	$ 0.5	1,684.1
Distribution by Former Parent, shares			48,800,000
Restricted shares, net	9.4	8.3		1.6			$ (0.5)
Restricted shares, net, shares							0
Other	(3)						$ (3)
Shares repurchased, shares							(100,000)
Ending balance at Dec. 31, 2018	1,684.5	0	$ 0.5	1,685.7	19.5	(17.7)	$ (3.5)
Ending balance, shares at Dec. 31, 2018			48,800,000				(100,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	113.3				113.3
Cash dividends on common stock	(9.9)				(9.9)
Other comprehensive loss	(2)					(2)
Capital contribution from Former Parent	0
Restricted shares, net	10.3			16			$ (5.7)
Restricted shares, net, shares			200,000				(200,000)
Other	(11)						$ (11)
Treasury Stock, Shares, Retired			(700,000)				700,000
Treasury Stock, Retired, Cost Method, Amount				(20.2)			$ 20.2
Stockholders' Equity, Other	$ 5.2			5.2
Shares repurchased, shares	361,442						(400,000)
Ending balance at Dec. 31, 2019	$ 1,790.4	$ 0	$ 0.5	$ 1,686.7	$ 122.9	$ (19.7)	$ 0
Ending balance, shares at Dec. 31, 2019			48,300,000				0

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	Dec. 31, 2019	Nov. 01, 2018
Statement of Stockholders' Equity [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Overview and Summary of Significant Accounting Policies Basis of Presentation On November 1, 2018, Arcosa, Inc. and its consolidated subsidiaries (“Arcosa,” the “Company,” “we,” or “our”) became an independent publicly-traded company as a result of the distribution by Trinity Industries, Inc. (“Trinity” or "Former Parent") of 100% of the outstanding shares of Arcosa, Inc. to Trinity’s stockholders (the “Separation”). Trinity stockholders received one share of Arcosa, Inc. common stock for every three shares of Trinity common stock held as of 5:00 p.m. local New York City time on October 17, 2018, the record date for the distribution. The transaction was structured to be tax-free to both Trinity and Arcosa stockholders for U.S. federal income tax purposes. The accompanying Consolidated and Combined Financial Statements present our historical financial position, results of operations, comprehensive income/loss, and cash flows in accordance with accounting principles generally accepted in the U.S. (“GAAP”). The combined financial statements for periods prior to the Separation were derived from Trinity’s consolidated financial statements and accounting records and prepared in accordance with GAAP for the preparation of carved-out combined financial statements. Through the date of the Separation, all revenues and costs as well as assets and liabilities directly associated with Arcosa have been included in the combined financial statements. Prior to the Separation, the combined financial statements also included allocations of certain selling, general, and administrative expenses provided by Trinity to Arcosa and allocations of related assets, liabilities, and the Former Parent’s net investment, as applicable. The allocations were determined on a reasonable basis; however, the amounts are not necessarily representative of the amounts that would have been reflected in the financial statements had the Company been an entity that operated independently of Trinity during the applicable periods. Following the Separation, the consolidated financial statements include the accounts of the Company and its subsidiaries and no longer include any allocations from Trinity. All normal and recurring adjustments necessary for a fair presentation of the financial position of the Company and the results of operations and cash flows have been made in conformity with GAAP. All significant intercompany accounts and transactions have been eliminated. Relationship with Former Parent and Related Entities Prior to the Separation, Arcosa was managed and operated in the normal course of business with other business units of Trinity. The accompanying combined financial results for periods prior to the Separation include sales and purchase transactions with Trinity and its subsidiaries in addition to certain shared costs which have been allocated to Arcosa and reflected as expenses in the Combined Statements of Operations. Transactions and allocations between Trinity and Arcosa are reflected in equity in the Combined Balance Sheets as Former Parent's net investment and in the Combined Statements of Cash Flows as a financing activity in Net transfers from/(to) Former Parent and affiliates. All transactions and allocations between Trinity and Arcosa prior to the Separation have been deemed paid between the parties, in cash, in the period in which the transaction or allocation was recorded in the Combined Financial Statements. Disbursements and cash receipts were made through centralized accounts payable and cash collection systems, respectively, which were operated by Trinity. As cash was disbursed and received by Trinity, it was accounted for by Arcosa through the Former Parent's net investment account. Allocations of current income taxes receivable or payable prior to the Separation were deemed to have been remitted to Arcosa or Trinity, respectively, in cash, in the period to which the receivable or payable applies. Corporate Costs/Allocations The combined financial results include an allocation of costs related to certain corporate functions incurred by Trinity for services that are provided to or on behalf of Arcosa. Corporate costs have been allocated to Arcosa using methods management believes are consistent and reasonable. Such cost allocations to Arcosa consist of (1) shared service charges and (2) corporate overhead costs. Shared service charges consist of monthly charges to each Trinity business unit for certain corporate functions such as information technology, human resources, and legal based on usage rates and activity units. Corporate overhead costs consist of costs not previously allocated to Trinity's business units and were allocated to Arcosa based on an analysis of each cost function and the relative benefits received by Arcosa for each of the periods. Corporate overhead costs allocated to Arcosa prior to the Separation totaled $26.0 million and $39.3 million for the ten months ended October 31, 2018 and the year ended December 31, 2017 , respectively. Corporate overhead costs are included in selling, general, and administrative expenses in the accompanying Consolidated and Combined Statements of Operations. Also see Note 4 Segment Information. The Consolidated and Combined Financial Statements of Arcosa for the years ended December 31, 2018 and 2017 may not include all of the actual expenses that would have been incurred had we operated as a standalone company during the periods presented and may not reflect our combined results of operations, financial position, and cash flows had we operated as a standalone company during the periods presented. Actual costs that would have been incurred if we had operated as a standalone company would depend on multiple factors, including organizational structure and strategic decisions made in various areas, including information technology and infrastructure. We also may incur additional costs associated with being a standalone, independent, publicly-traded company that were not included in the expense allocations and, therefore, would result in additional costs that are not reflected in our historical results of operations, financial position, and cash flows. Other Transactions with Trinity Businesses For the years ended December 31, 2018 and 2017 , the Company had sales to Trinity businesses of $160.3 million and $148.3 million , respectively, and purchases from Trinity businesses of $44.5 million and $53.2 million , respectively. Subsequent to the Separation, Trinity is no longer considered a related entity. Stockholders' Equity In December 2018 , the Company’s Board of Directors (the "Board") authorized a $50 million share repurchase program effective December 5, 2018 through December 31, 2020 . For the year ended December 31, 2019 , Company repurchased 361,442 shares at a cost of $11.0 million . As of December 31, 2019 , the Company had a remaining authorization of $36.0 million under the program. Prior to the Separation, the Company filed its Restated Certificate of Incorporation which authorizes the issuance of 200 million shares of common stock at a par value of $0.01 per share. Revenue Recognition Revenue is measured based on the allocation of the transaction price in a contract to satisfied performance obligations. The transaction price does not include any amounts collected on behalf of third parties. The Company recognizes revenue when it satisfies a performance obligation by transferring control over a product or service to a customer. The following is a description of principal activities from which the Company generates its revenue, separated by reportable segments. Payments for our products and services are generally due within normal commercial terms. For a further discussion regarding the Company’s reportable segments, see Note 4 Segment Information. Construction Products Group The Construction Products Group recognizes revenue when the customer has accepted the product and legal title of the product has passed to the customer. Energy Equipment Group Within the Energy Equipment Group, revenue is recognized for our wind tower, certain utility structure, and certain storage tank product lines over time as the products are manufactured using an input approach based on the costs incurred relative to the total estimated costs of production. We recognize revenue over time for these products as they are highly customized to the needs of an individual customer resulting in no alternative use to the Company if not purchased by the customer after the contract is executed, and we have the right to bill the customer for our work performed to date plus at least a reasonable profit margin for work performed. As of December 31, 2019 and 2018 , we had a contract asset of $50.8 million and $44.0 million , respectively, which is included in receivables, net of allowance, within the Consolidated Balance Sheets. For all other products, revenue is recognized when the customer has accepted the product and legal title of the product has passed to the customer. Transportation Products Group The Transportation Products Group recognizes revenue when the customer has accepted the product and legal title of the product has passed to the customer. Unsatisfied Performance Obligations The following table includes estimated revenue expected to be recognized in future periods related to performance obligations that are unsatisfied or partially satisfied as of December 31, 2019 and the percentage of the outstanding performance obligations as of December 31, 2019 expected to be delivered during 2020 : Unsatisfied performance obligations at December 31, 2019 Total Percent expected to be delivered in 2020 (in millions) Energy Equipment Group: Wind towers and utility structures $ 596.8 86.0 % Other $ 36.2 100.0 % Transportation Products Group: Inland barges $ 346.9 100.0 % The remainder of the unsatisfied performance obligations for wind towers and utility structures are expected to be delivered during 2021 . Income Taxes The liability method is used to account for income taxes. Deferred income taxes represent the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Valuation allowances reduce deferred tax assets to an amount that will more likely than not be realized. The Company regularly evaluates the likelihood of realization of tax benefits derived from positions it has taken in various federal and state filings after consideration of all relevant facts, circumstances, and available information. For those tax positions that are deemed more likely than not to be sustained, the Company recognizes the benefit it believes is cumulatively greater than 50% likely to be realized. To the extent the Company were to prevail in matters for which accruals have been established or be required to pay amounts in excess of recorded reserves, the effective tax rate in a given financial statement period could be materially impacted. Prior to the Separation, the Company’s operating results were included in the Former Parent’s various consolidated U.S. federal and state income tax returns, as well as non-U.S. tax filings. In the Company’s Combined Financial Statements for the periods prior to the Separation, income tax expense and deferred tax balances have been recorded as if the Company filed tax returns on a standalone basis separate from the Former Parent. The separate return method applies the accounting guidance for income taxes to the standalone financial statements as if the Company was a separate taxpayer and a standalone enterprise for the periods presented. Financial Instruments The Company considers all highly liquid debt instruments to be cash and cash equivalents if purchased with a maturity of three months or less. Financial instruments that potentially subject the Company to a concentration of credit risk are primarily cash investments and receivables. The Company places its cash investments in bank deposits and highly-rated money market funds, and its investment policy limits the amount of credit exposure to any one commercial issuer. We seek to limit concentrations of credit risk with respect to receivables with control procedures that monitor the credit worthiness of customers, together with the large number of customers in the Company's customer base and their dispersion across different industries and geographic areas. As receivables are generally unsecured, the Company maintains an allowance for doubtful accounts based upon the expected collectibility of all receivables. Receivable balances determined to be uncollectible are charged against the allowance. To accelerate the conversion to cash, the Company may sell a portion of its trade receivables to a third party. The Company has no continuing involvement or recourse related to these receivables once they are sold, and the impact of these transactions in the Company's Consolidated Statements of Operations for the year ended December 31, 2019 was not significant. The carrying values of cash, receivables, and accounts payable are considered to be representative of their respective fair values. Inventories Inventories are valued at the lower of cost or net realizable value. Cost is determined principally on the first in first out method. The value of inventory is adjusted for damaged, obsolete, excess, or slow-moving inventory. Work in process and finished goods include material, labor, and overhead. During the year ended December 31, 2018, the Company recorded a $6.1 million write-off on finished goods inventory related to an order for a single customer in our utility structures business. Property, Plant, and Equipment Property, plant, and equipment are stated at cost and depreciated or depleted over their estimated useful lives, primarily using the straight-line method. The estimated useful lives are: buildings and improvements - 3 to 30 years ; leasehold improvements - the lesser of the term of the lease or 11 years ; machinery and equipment - 2 to 10 years ; and information systems hardware and software - 2 to 5 years . Depletion of mineral reserves is calculated based on estimated proven and probable reserves using the units-of-production method on a quarry-by-quarry basis. The costs of ordinary maintenance and repair are charged to operating costs as incurred. Long-lived Assets The Company periodically evaluates the carrying value of long-lived assets to be held and used for potential impairment. The carrying value of long-lived assets to be held and used is considered impaired only when the carrying value is not recoverable through undiscounted future cash flows and the fair value of the assets is less than their carrying value. Fair value is determined primarily using the anticipated cash flows discounted at a rate commensurate with the risks involved or market quotes as available. Impairment losses on long-lived assets held for sale are determined in a similar manner, except that fair values are reduced by the estimated cost to dispose of the assets. See Note 2 Acquisitions and Divestitures for discussion of the impairment charge recorded during the year ended December 31, 2018 on businesses that were subsequently divested. Based on the Company's evaluations, no additional impairment charges were determined to be necessary as of December 31, 2019 and December 31, 2017 . Goodwill and Intangible Assets Goodwill is required to be tested for impairment annually, or on an interim basis whenever events or circumstances change indicating that the carrying amount of the goodwill might be impaired. The quantitative goodwill impairment test is a two-step process with step one requiring the comparison of the reporting unit's estimated fair value with the carrying amount of its net assets. If necessary, step two of the impairment test determines the amount of goodwill impairment to be recorded when the reporting unit's recorded net assets exceed its fair value. Impairment is assessed at the “reporting unit” level by applying a fair value-based test for each unit with recorded goodwill. The estimates and judgments that most significantly affect the fair value calculations are assumptions, consisting of level three inputs, related to revenue and operating profit growth, discount rates, and exit multiples. As of December 31, 2019 and 2018 , the Company's annual impairment test of goodwill was completed at the reporting unit level and no impairment charges were determined to be necessary. The net book value of intangible assets totaled $51.7 million and $55.2 million as of December 31, 2019 and 2018 , respectively, and included $34.1 million not subject to amortization related to an acquired trademark. The remaining intangible assets with a gross cost of $44.6 million as of December 31, 2019 and 2018 , are amortized over their estimated useful lives ranging from 1 to 12 years , and primarily relate to acquired customer relationships. Total amortization expense from intangible assets was $3.4 million , $4.7 million , and $5.0 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. Intangible assets were evaluated for potential impairment as of December 31, 2019 and 2018 . Workers ’ Compensation The Company is effectively self-insured for workers ’ compensation claims. A third party administrator is used to process claims. We accrue our workers' compensation liability based upon independent actuarial studies. Warranties The Company provides various express, limited product warranties that generally range from 1 to 5 years depending on the product. The warranty costs are estimated using a two-step approach. First, an engineering estimate is made for the cost of all claims that have been asserted by customers. Second, based on historical, accepted claims experience, a cost is accrued for all products still within a warranty period for which no claims have been filed. The Company provides for the estimated cost of product warranties at the time revenue is recognized related to products covered by warranties and assesses the adequacy of the resulting reserves on a quarterly basis. As of December 31, 2019 and 2018 , the Company's accrual for warranty costs was $2.6 million and $2.9 million , respectively, which is included in accrued liabilities within the Consolidated Balance Sheets. Derivative Instruments The Company may, from time to time, use derivative instruments to mitigate the impact of changes in interest rates or changes in foreign currency exchange rates. For derivative instruments designated as hedges, the Company formally documents the relationship between the derivative instrument and the hedged item, as well as the risk management objective and strategy for the use of the derivative instrument. This documentation includes linking the derivative to specific assets or liabilities on the balance sheet, commitments, or forecasted transactions. At the time a derivative instrument is entered into, and at least quarterly thereafter, the Company assesses whether the derivative instrument is effective in offsetting the changes in fair value or cash flows of the hedged item. Any change in the fair value of the hedged instrument is recorded in accumulated other comprehensive loss ("AOCL") as a separate component of stockholders' equity and reclassified into earnings in the period during which the hedged transaction affects earnings. The Company monitors its derivative positions and the credit ratings of its counterparties and does not anticipate losses due to counterparties' non-performance. Foreign Currency Translation Certain operations outside the U.S. prepare financial statements in currencies other than the U.S. dollar. The income statement amounts are translated at average exchange rates for the year, while the assets and liabilities are translated at year-end exchange rates. Translation adjustments are accumulated as a separate component of stockholders' equity and other comprehensive income. The functional currency of our Mexico operations is considered to be the U.S. dollar. The functional currency of our Canadian operations is considered to be the Canadian dollar. Other Comprehensive Income (Loss) Other comprehensive income (loss) consists of foreign currency translation adjustments and the effective unrealized gains and losses on the Company's derivative financial instruments, the sum of which, along with net income, constitutes comprehensive net income (loss). See Note 12 Accumulated Other Comprehensive Loss. All components are shown net of tax. Recent Accounting Pronouncements Recently adopted accounting pronouncements Effective as of January 1, 2018, the Company adopted Accounting Standards Update No. 2014-09, “Revenue from Contracts with Customers,” (“ASU 2014-09”), which provides common revenue recognition guidance for GAAP. Under ASU 2014-09, an entity recognizes revenue when it transfers promised goods or services to customers in an amount that reflects what it expects to receive in exchange for the goods or services. It also requires additional detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenues and cash flows arising from contracts with customers. The Company applied ASU 2014-09 to all contracts that were not complete as of January 1, 2018 using the modified retrospective method of adoption, resulting in a reduction to Former Parent's Net Investment of $4.0 million , net of tax, as of January 1, 2018 related to the cumulative effect of applying this standard. Therefore, the comparative information for the year ended December 31, 2017 has not been adjusted and continue to be reported under ASC Topic 605. The primary impact of adopting the standard is a change in the timing of revenue recognition for our wind towers, certain utility structures, and certain storage tank product lines within our Energy Equipment Group. Previously, the Company recognized revenue when the product was delivered. Under ASU 2014-09, revenue is recognized over time as the products are manufactured. Revenue recognition policies in our other business segments remain substantially unchanged. Effective as of January 1, 2019, the Company adopted Accounting Standards Update No. 2016-02, “Leases”, (“ASU 2016-02”), which amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets and making targeted changes to lessor accounting. The Company elected to use the optional transition method that allows the Company to apply the provisions of the standard at the effective date without adjusting the comparative prior periods. In addition, we elected the package of practical expedients permitted under the transition guidance within the new standard which allowed us to carry forward the historical lease classification. The cumulative effect of adopting the standard on the opening balance of retained earnings was not significant. The primary impact of adopting the standard was the recognition of a right-of-use asset of $23.7 million and corresponding lease liability of $27.5 million for our operating leases included in other assets and other liabilities, respectively, on the Consolidated Balance Sheet. See Note 8 Leases for further discussion. The Company has implemented processes and a lease accounting system to ensure adequate internal controls were in place to assess our contracts and enable proper accounting and reporting of financial information upon adoption. Recently issued accounting pronouncements not adopted as of December 31, 2019 In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2016-13, “Financial Instruments - Credit Losses”, (“ASU 2016-13”), which amends the existing accounting guidance for recognizing credit losses on financial assets and certain other instruments not measured at fair value through net income, including financial assets measured at amortized cost, such as trade receivables and contract assets. ASU 2016-13 replaces the existing incurred loss impairment model with an expected credit loss model that requires consideration of a broader range of information to estimate expected credit losses over the lifetime of the asset. The new guidance is expected to result in earlier recognition of credit losses. ASU 2016-13 will become effective for public companies during interim and annual reporting periods beginning after December 15, 2019, with early adoption permitted. The Company will adopt the new standard on January 1, 2020 and does not expect the adoption of the guidance to have a material impact on our consolidated financial statements. In December 2019, the FASB issued Accounting Standards Updated No. 2019-12, “Simplifying the Accounting for Income Taxes”, (“ASU 2019-12”), which simplifies the accounting for income taxes by removing certain exceptions to the general principles for income taxes. ASU 2019-12 will become effective for public companies during interim and annual reporting periods beginning after December 15, 2020, with early adoption permitted. We are currently evaluating the impact of adoption on our consolidated financial statements. Management's Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Reclassifications Certain prior year balances have been reclassified in the Consolidated and Combined Financial Statements to conform with the 2019 presentation.

Acquisitions and Divestitures

Acquisitions and Divestitures	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Acquisitions and Divestitures	Acquisitions and Divestitures The Company's acquisition and divestiture activities are summarized below: Year Ended December 31, 2019 2018 2017 (in millions) Acquisitions: Purchase price $ 39.2 $ 334.1 $ 63.0 Net cash paid $ 32.9 $ 333.2 $ 47.5 Goodwill recorded $ 12.6 $ 120.9 $ 25.0 Acquisitions - ACG Materials On December 5, 2018, we completed the stock acquisition of ACG Materials (“ACG”), a producer of specialty materials and aggregates which is included in our Construction Products Group. The purchase price of $309.1 million was funded with a combination of cash on-hand and a $180.0 million borrowing under the Company's credit facility. Acquisition-related transaction costs incurred after the Separation were insignificant. Costs incurred by the Former Parent prior to the Separation were included in the allocation of corporate costs in accordance with the methodology described in Note 1. The acquisition was recorded as a business combination with valuations of the acquired assets and liabilities at their acquisition date fair value using level three inputs, defined as unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The following table represents our final purchase price allocation (in millions): Accounts receivable $ 23.8 Inventories 12.5 Property, plant, and equipment 77.8 Mineral reserves 137.3 Goodwill 105.5 Other assets 6.3 Accounts payable (10.2 ) Accrued and other liabilities (14.5 ) Capital lease obligations (8.3 ) Deferred income taxes (21.1 ) Total net assets acquired $ 309.1 The goodwill acquired, none of which is tax deductible, primarily relates to ACG's geographic footprint, market position, and existing workforce. Revenues included in the Consolidated Statement of Operations from the date of the acquisition were approximately $11.7 million during the year ended December 31, 2018, whereas operating profit during the same period was insignificant. The following table represents the unaudited pro-forma consolidated operating results of the Company as if the ACG acquisition had been completed on January 1, 2017. The unaudited pro-forma information makes certain adjustments to depreciation, depletion, and amortization expense to reflect the fair value recognized in the purchase price allocation, as well as to align ACG's capital structure and debt financing with that of the Company at the acquisition date. As a measure of unaudited pro-forma earnings, we have presented income before income taxes because our effective tax rates for 2018 and 2017 were impacted by one-time effects of the Act that would be impracticable to calculate for ACG. The unaudited pro-forma information should not be considered indicative of the results that would have occurred if the acquisition had been completed on January 1, 2017, nor is such unaudited pro-forma information necessarily indicative of future results. Year Ended December 31, 2018 Year Ended December 31, 2017 (in millions) Revenues $ 1,604.1 $ 1,594.4 Income before income taxes $ 97.6 $ 133.6 Acquisitions - Other In June 2019, we completed acquisitions of certain assets and liabilities of an inland barge components business within our Transportation Products Group and the acquisition of certain assets and liabilities of a construction aggregates business in our Construction Products Group. In August 2019, we completed the acquisitions of certain assets and liabilities of two construction aggregates businesses in our Construction Products Group. The total purchase price for the four businesses acquired in 2019 was $39.2 million , a portion of which includes estimated payments to the seller of a construction aggregates business over the next 10 years. The acquisitions have been recorded as business combinations based on preliminary valuations of the assets acquired and liabilities assumed at their acquisition date fair value using level three inputs. The valuation resulted in the recognition of $12.2 million of goodwill in our Transportation Products Group and $0.4 million in our Construction Products Group. Such assets and liabilities were not significant in relation to assets and liabilities at the consolidated and segment level. In March 2018, we completed the acquisition of certain assets of an inland barge business with a purchase price and net cash paid of $25.0 million . The acquisition was recorded as a business combination based on valuations of the acquired assets and liabilities at their acquisition date fair value using level three inputs. The valuation resulted in the recognition of $9.5 million of goodwill in our Transportation Products Group. Such assets and liabilities were not significant in relation to assets and liabilities at the consolidated and combined or segment level. In May 2017, we completed the acquisition of the assets of a lightweight aggregates business paid for with cash of $6.2 million . In October 2017, we completed the acquisition of the assets of a lightweight aggregates business paid for with shares of Trinity stock valued at $14.7 million . In July 2017, we completed the acquisition of the assets of a trench shoring products business for $42.1 million . All three acquisitions were in our Construction Products Group. These acquisitions were recorded as business combinations based on valuations of the acquired assets and liabilities at their acquisition date fair value using level three inputs. Such assets and liabilities were not significant in relation to assets and liabilities at the consolidated or segment level. Acquisitions - Cherry On January 6, 2020, we completed the stock acquisition of Cherry Industries, Inc. and affiliated entities (“Cherry”), a leading producer of natural and recycled aggregates in the Houston, Texas market which will be included in our Construction Products Group. The purchase price of approximately $298.0 million was funded with a combination of cash on-hand and advances under a new $150.0 million five-year term loan. See Note 7 Debt for additional information on our credit facility. Transaction costs incurred during the year ended December 31, 2019 related to the Cherry acquisition were not significant. The acquisition will be recorded as a business combination. We expect to complete our purchase price allocation as soon as reasonably possible not to exceed one year from the acquisition date. Due to the timing of the acquisition, additional quantitative disclosures are, at this time, impracticable. Divestitures During the fourth quarter of 2018, the Company completed the divestiture of certain businesses whose revenues were included in the Other component of the Energy Equipment Group. The net proceeds from these divestitures were not significant. Prior to the sales, the Company recognized a pre-tax impairment charge of $23.2 million on these businesses. We have concluded that the divestiture of these businesses did not represent a strategic shift that would result in a material effect on our operations and financial results; therefore, these disposals have not been reflected in discontinued operations in our Consolidated and Combined Financial Statements. There was no divestiture activity during the years ended December 31, 2019 and December 31, 2017 .

Fair Value Accounting

Fair Value Accounting	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Accounting	Fair Value Accounting Assets and liabilities measured at fair value on a recurring basis are summarized below: Fair Value Measurement as of December 31, 2019 Level 1 Level 2 Level 3 Total (in millions) Assets: Cash equivalents $ 155.3 $ — $ — $ 155.3 Total assets $ 155.3 $ — $ — $ 155.3 Liabilities: Interest rate hedge (1) $ — $ 4.3 $ — $ 4.3 Contingent consideration (2) — — 6.4 6.4 Total liabilities $ — $ 4.3 $ 6.4 $ 10.7 Fair Value Measurement as of December 31, 2018 Level 1 Level 2 Level 3 Total (in millions) Assets: Cash equivalents $ 30.0 $ — $ — $ 30.0 Total assets $ 30.0 $ — $ — $ 30.0 Liabilities: Interest rate hedge (1) $ — $ 1.2 $ — $ 1.2 Total liabilities $ — $ 1.2 $ — $ 1.2 (1) Included in other liabilities on the Consolidated Balance Sheet. (2) Current portion included in accrued liabilities and non-current portion included in other liabilities on the Consolidated Balance Sheets. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for that asset or liability in an orderly transaction between market participants on the measurement date. An entity is required to establish a fair value hierarchy that maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. The three levels of inputs that may be used to measure fair values are listed below: Level 1 – This level is defined as quoted prices in active markets for identical assets or liabilities. The Company’s cash equivalents are instruments of the U.S. Treasury or highly-rated money market mutual funds. Level 2 – This level is defined as observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Interest rate hedges are valued at exit prices obtained from each counterparty. See Note 7 Debt. Level 3 – This level is defined as unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Contingent consideration relates to estimated future payments owed to the sellers of businesses previously acquired. We estimate the fair value of the contingent consideration using a discounted cash flow model. The fair value is sensitive to changes in the forecast of sales and changes in discount rates and is reassessed quarterly based on assumptions used in our latest projections.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information The Company reports operating results in three principal business segments: Construction Products. The Construction Products segment produces and sells construction aggregates and manufactures and sells trench shields and shoring products and services for infrastructure-related projects. Energy Equipment. The Energy Equipment segment manufactures and sells products for energy-related businesses, including structural wind towers, steel utility structures for electricity transmission and distribution, and storage and distribution tanks. Transportation Products. The Transportation Products segment manufactures and sells products for the inland waterway and rail transportation industries including barges, barge-related products, axles, and couplers. The financial information for these segments is shown in the tables below. We operate principally in North America. Year Ended December 31, 2019 Revenues Operating Profit (Loss) Assets Depreciation, Depletion, & Amortization Capital Expenditures Construction aggregates $ 364.7 Other 75.0 Construction Products Group 439.7 $ 52.7 $ 785.0 $ 38.0 $ 30.2 Wind towers and utility structures 625.4 Other 211.2 Energy Equipment Group 836.6 100.7 934.9 27.9 25.0 Inland barges 293.9 Steel components 171.8 Transportation Products Group 465.7 46.8 316.5 16.3 21.8 Segment Totals before Eliminations and Corporate 1,742.0 200.2 2,036.4 82.2 77.0 Corporate — (47.3 ) 266.1 3.6 8.4 Eliminations (5.1 ) — — — — Consolidated Total $ 1,736.9 $ 152.9 $ 2,302.5 $ 85.8 $ 85.4 Year Ended December 31, 2018 Revenues Operating Profit (Loss) Assets Depreciation, Depletion, & Amortization Capital Expenditures Construction aggregates $ 217.9 Other 74.4 Construction Products Group 292.3 $ 50.4 $ 769.8 $ 21.9 $ 17.2 Wind towers and utility structures 582.9 Other 197.2 Energy Equipment Group 780.1 28.6 976.2 29.7 16.0 Inland barges 170.2 Steel components 221.2 Transportation Products Group 391.4 48.4 305.0 15.5 10.3 All Other — (0.1 ) — — — Segment Totals before Eliminations and Corporate 1,463.8 127.3 2,051.0 67.1 43.5 Corporate — (32.1 ) 121.2 0.5 1.3 Eliminations (3.4 ) (0.3 ) — — — Consolidated and Combined Total $ 1,460.4 $ 94.9 $ 2,172.2 $ 67.6 $ 44.8 Year Ended December 31, 2017 Revenues Operating Profit (Loss) Assets Depreciation, Depletion, & Amortization Capital Expenditures Construction aggregates $ 204.9 Other 54.0 Construction Products Group 258.9 $ 53.7 $ 391.2 $ 18.4 $ 48.9 Wind towers and utility structures 652.1 Other 192.0 Energy Equipment Group 844.1 78.4 928.8 30.2 27.7 Inland barges 157.9 Steel components 205.4 Transportation Products Group 363.3 39.0 257.5 17.1 5.8 All Other — (0.1 ) — — — Segment Totals before Eliminations and Corporate 1,466.3 171.0 1,577.5 65.7 82.4 Corporate — (39.3 ) 25.0 — — Eliminations (3.9 ) — — — — Combined Total $ 1,462.4 $ 131.7 $ 1,602.5 $ 65.7 $ 82.4 Corporate assets are composed of cash and cash equivalents, certain property, plant, and equipment, and other assets. Capital expenditures exclude amounts paid for business acquisitions but include amounts paid for the acquisition of land and reserves in our Construction Products Group. Revenues from one customer included in the Energy Equipment Group constituted 18.2% , 19.4% , and 22.9% of consolidated or combined revenues for the years ended December 31, 2019 , 2018 , and 2017 , respectively. Revenues and operating profit for our Mexico operations for the years ended December 31, 2019 , 2018 , and 2017 are presented below. Our Canadian operations were not significant in relation to the consolidated financial statements. Year Ended December 31, 2019 2018 2017 (in millions) Mexico: Revenues: External $ 110.1 $ 108.2 $ 118.2 Intercompany 88.0 82.3 62.6 $ 198.1 $ 190.5 $ 180.8 Operating profit $ 4.8 $ (11.0 ) $ 1.4 Total assets and long-lived assets for our Mexico operations as of December 31, 2019 and 2018 are presented below: Total Assets Long-Lived Assets December 31, 2019 2018 2019 2018 (in millions) Mexico $ 202.2 $ 203.8 $ 85.5 $ 85.8

Property, Plant, and Equipment

Property, Plant, and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment	Property, Plant, and Equipment The following table summarizes the components of property, plant, and equipment as of December 31, 2019 and 2018 . December 31, December 31, (in millions) Land (1) $ 331.4 $ 316.5 Buildings and improvements 280.5 267.5 Machinery and other 755.7 715.9 Construction in progress 38.6 28.8 1,406.2 1,328.7 Less accumulated depreciation and depletion (590.0 ) (525.7 ) $ 816.2 $ 803.0 (1) Includes depletable land of $211.0 million as of December 31, 2019 and $201.9 million as of December 31, 2018 . We did not capitalize any interest expense as part of the construction of facilities and equipment during 2019 or 2018 . We estimate the fair market value of properties no longer in use based on the location and condition of the properties, the fair market value of similar properties in the area, and the Company's experience selling similar properties in the past. As of December 31, 2019 , the Company had non-operating plants with a net book value of $47.4 million . Our estimated fair value of these assets exceeds their book value.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill Goodwill by segment is as follows: December 31, December 31, (in millions) Construction Products Group $ 166.2 $ 171.7 Energy Equipment Group 416.9 416.9 Transportation Products Group 38.8 26.6 $ 621.9 $ 615.2 As of December 31, 2019 , the Company's annual impairment test of goodwill was completed at the reporting unit level and no impairment charges were determined to be necessary. The decrease in the Construction Products Group goodwill during the year ended December 31, 2019 is primarily due to the refinement of the purchase price allocation for ACG. The increase in the Transportation Products Group goodwill during the year ended December 31, 2019

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt The following table summarizes the components of debt as of December 31, 2019 and December 31, 2018 : December 31, December 31, (in millions) Revolving credit facility $ 100.0 $ 180.0 Finance leases 7.3 5.5 Total debt $ 107.3 $ 185.5 On November 1, 2018, the Company entered into a $400.0 million unsecured revolving credit facility that matures in November 2023 . The interest rates under the facility are variable based on LIBOR or an alternate base rate plus a margin. A commitment fee accrues on the average daily unused portion of the revolving facility. The margin for borrowing and commitment fee rate are determined based on Arcosa’s leverage as measured by a consolidated total indebtedness to consolidated EBITDA ratio. The margin for borrowing ranges from 1.25% to 2.00% and was set at LIBOR plus 1.25% as of December 31, 2019 . The commitment fee rate ranges from 0.20% to 0.35% and was set at 0.20% at December 31, 2019 . As of December 31, 2019 , we had $100.0 million of outstanding loans borrowed under the facility and there were approximately $42.5 million in letters of credit issued, leaving $257.5 million available for borrowing. All of the outstanding letters of credit as of December 31, 2019 are expected to expire in 2020 . The majority of our letters of credit obligations support the Company’s various insurance programs and warranty claims and generally renew by their terms each year. The Company's revolving credit facility requires the maintenance of certain ratios related to leverage and interest coverage. As of December 31, 2019 , we were in compliance with all such financial covenants. Borrowings under the credit facility are guaranteed by certain wholly-owned subsidiaries of the Company. The carrying value of borrowings under our revolving credit facility approximates fair value because the interest rate adjusts to the market interest rate (Level 3 input). See Note 3 Fair Value Accounting. As of December 31, 2019 , the Company had $1.2 million of unamortized debt issuance cost related to the revolving credit facility, which is included in other assets on the Consolidated Balance Sheet. The remaining principal payments under existing debt agreements as of December 31, 2019 are as follows: 2020 2021 2022 2023 2024 Thereafter (in millions) Revolving credit facility $ — $ — $ — $ 100.0 $ — $ — On January 2, 2020 , the Company entered into an Amended and Restated Credit Agreement to increase the revolving credit facility from $400.0 million to $500.0 million and added a term loan facility of $150.0 million , in each case with a maturity date of January 2, 2025 . The mechanism for determining and the applicable ranges for the interest rate margin and commitment fee rate are unchanged. The interest rate on the revolving credit facility was initially set at one-month LIBOR plus 1.50% and the interest rate on the term loan facility was initially set at three-month LIBOR plus 1.50% . The commitment fee rate on both facilities was initially set at set at 0.25% . The entire term loan was advanced on January 2, 2020 in connection with the closing of the acquisition of Cherry. See Note 2 Acquisitions and Divestitures. Interest rate hedges In December 2018, the Company entered into an interest rate swap instrument, effective as of January 2, 2019 and expiring in 2023, to reduce the effect of changes in the variable interest rates associated with borrowings under the revolving credit facility. The instrument carried an initial notional amount of $100 million , thereby hedging the first $100 million of borrowings under the credit facility. The instrument effectively fixes the LIBOR component of the credit facility borrowings at a monthly rate of 2.71% . As of December 31, 2019 , the Company has recorded a liability of $4.3 million

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Leases We have various leases primarily for office space and certain equipment. At inception, we determine if an arrangement contains a lease and whether that lease meets the classification criteria of a finance or operating lease. For leases that contain options to purchase, terminate, or extend, such options are included in the lease term when it is reasonably certain that the option will be exercised. Some of the Company's lease arrangements contain lease components and non-lease components which are accounted for as a single lease component as we have elected the practical expedient to group lease and non-lease components for all leases. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on information available at commencement date in determining the present value of lease payments. Operating Leases The following table presents information about the amount, timing, and uncertainty of cash flows arising from the Company's operating leases as of December 31, 2019 . December 31, 2019 (in millions) Maturity of Lease Liabilities 2020 $ 6.4 2021 4.0 2022 2.6 2023 2.0 2024 1.7 Thereafter 6.0 Total undiscounted operating lease payments 22.7 Less imputed interest (3.7 ) Present value of operating lease liabilities $ 19.0 Balance Sheet Classification Other assets $ 15.6 Accrued liabilities $ 5.5 Other liabilities 13.5 Total operating lease liabilities $ 19.0 Other Information Weighted average remaining lease term 5.8 years Weighted average discount rate 4.8 % Operating lease costs were $8.2 million during the year ended December 31, 2019 . Costs related to variable lease rates or leases with terms less than twelve months were not significant. Cash paid for amounts included in the measurement of operating lease liabilities was $7.8 million during the year ended December 31, 2019 and is included in operating cash flows. The additional right-of-use assets recognized as non-cash asset additions that resulted from new operating lease liabilities during the year ended December 31, 2019 were not significant. Finance Leases Finance leases are included in property, plant, and equipment, net and debt on the consolidated balance sheets. The associated amortization expense and interest expense are included in depreciation and interest expense, respectively, on the consolidated income statements. These leases are not material to the consolidated financial statements as of December 31, 2019 . Disclosures related to periods prior to adoption of ASU 2016-02 December 31, 2018 (in millions) Future Minimum Rent Expense 2019 $ 7.7 2020 5.7 2021 3.5 2022 2.3 2023 1.8 Thereafter 7.6 Total undiscounted operating lease payments $ 28.6

Other, Net

Other, Net	12 Months Ended
	Dec. 31, 2019
Other Income and Expenses [Abstract]
Other, Net	Other, Net Other, net (income) expense consists of the following items: Year Ended December 31, 2019 2018 2017 (in millions) Interest income $ (1.4 ) $ (0.4 ) $ (0.1 ) Foreign currency exchange transactions 1.5 (0.2 ) 2.2 Other (0.8 ) (0.4 ) (0.5 ) Other, net (income) expense $ (0.7 ) $ (1.0 ) $ 1.6

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of the provision for income taxes are as follows: Year Ended December 31, 2019 2018 2017 (in millions) Current: Federal $ 7.6 $ (5.4 ) $ 29.3 State 3.0 0.8 0.5 Foreign 5.6 1.5 0.3 Total current 16.2 (3.1 ) 30.1 Deferred: Federal: Effect of Tax Cuts and Jobs Act — (1.5 ) (6.2 ) Other 22.6 24.8 16.6 22.6 23.3 10.4 State (0.6 ) 5.4 0.9 Foreign (4.7 ) (6.3 ) (1.0 ) Total deferred 17.3 22.4 10.3 Provision $ 33.5 $ 19.3 $ 40.4 The provision for income taxes results in effective tax rates that differ from the statutory rates. The following is a reconciliation between the statutory U.S. federal income tax rate and the Company’s effective income tax rate on income before income taxes: Year Ended December 31, 2019 2018 2017 Statutory rate 21.0 % 21.0 % 35.0 % State taxes 3.1 3.1 2.5 Domestic production activities deduction — — (2.1 ) Changes in valuation allowances and reserves (1.3 ) (1.2 ) 1.3 Changes in tax reserves (0.3 ) (1.4 ) 0.8 Effect of Tax Cuts and Jobs Act — (1.6 ) (5.0 ) Prior year true-ups (0.5 ) (0.4 ) (2.2 ) Foreign adjustments 0.6 2.4 1.8 Other, net 0.2 (1.6 ) (1.0 ) Effective rate 22.8 % 20.3 % 31.1 % The Tax Cuts and Jobs Act ("the Act") was enacted on December 22, 2017. The Act reduced the U.S. federal corporate income tax rate from 35% to 21% , required companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and created new taxes on certain foreign-sourced earnings. For the year ended December 31, 2017 , we recognized a provisional benefit of $6.2 million , primarily related to the impact of the Act on our deferred taxes. During the year ended December 31, 2018 , we finalized the accounting for the enactment of the Act and recorded an additional $1.5 million benefit, primarily as a result of the true-up of our deferred taxes. There was no additional impact to the year-ended December 31, 2019 . Income (loss) before income taxes for the December 31, 2019 , 2018 , and 2017 was $143.6 million , $106.6 million , and $139.9 million , respectively, for U.S. operations, and $3.2 million , $(11.6) million , and $(9.8) million , respectively, for foreign operations, principally Mexico and Canada. The Company provides deferred income taxes on the unrepatriated earnings of its foreign operations where it results in a deferred tax liability. Deferred income taxes represent the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The components of deferred tax liabilities and assets are as follows: December 31, 2019 2018 (in millions) Deferred tax liabilities: Depreciation, depletion, and amortization $ 109.1 $ 103.2 Total deferred tax liabilities 109.1 103.2 Deferred tax assets: Workers compensation, pensions, and other benefits 21.6 16.2 Warranties and reserves 1.7 2.2 Tax loss carryforwards and credits 14.8 31.0 Inventory 22.7 10.8 Accrued liabilities and other 1.0 (2.7 ) Total deferred tax assets 61.8 57.5 Net deferred tax assets (liabilities) before valuation allowances (47.3 ) (45.7 ) Valuation allowances 4.8 5.7 Adjusted net deferred tax assets (liabilities) $ (52.1 ) $ (51.4 ) At December 31, 2019 , the Company had $22.0 million of federal consolidated net operating loss carryforwards, primarily from businesses acquired, and $0.6 million of tax-effected state loss carryforwards remaining. In addition, the Company had $36.9 million of foreign net operating loss carryforwards that will begin to expire in the year 2022 . We have established a valuation allowance for state and foreign tax operating losses and credits that we have estimated may not be realizable. Income tax has not been recognized on the excess of the amount for financial reporting over the tax basis of investments in foreign subsidiaries that is indefinitely reinvested outside the United States. This amount becomes taxable upon a repatriation of assets from the subsidiary or a sale or liquidation of the subsidiary. The amount of such temporary differences totaled approximately $79.4 million as of December 31, 2019 . Determination of the amount of any unrecognized deferred income tax liability on this temporary difference is not practicable because of the complexities of the hypothetical calculation. Taxing authority examinations We have multiple federal tax return filings that are subject to examination by the Internal Revenue Service. We filed the initial Arcosa, Inc. federal return for 2018 and it will remain open for three years. The 2015-2018 tax years are open for the ACG federal returns. We have various subsidiaries that file separate state tax returns and are subject to examination by taxing authorities at different times. The entities are generally open for their 2015 tax years and forward. We have various subsidiaries in Mexico that file separate tax returns and are subject to examination by taxing authorities at different times. The entities are generally open for their 2014 tax years and forward. Unrecognized tax benefits The change in unrecognized tax benefits for the years ended December 31, 2019 , 2018 , and 2017 was as follows: December 31, 2019 2018 2017 (in millions) Beginning balance $ 0.5 $ 1.3 $ 7.4 Additions for tax positions related to the current year — — — Additions for tax positions of prior years — 0.1 0.2 Reductions for tax positions of prior years — — — Settlements — — (6.0 ) Expiration of statute of limitations (0.5 ) (0.9 ) (0.3 ) Ending balance $ — $ 0.5 $ 1.3 The additions for tax positions of prior years of $0.1 million and $0.2 million for the years ended December 31, 2018 and 2017 , respectively, are due to foreign tax positions. Settlements for the year ended December 31, 2017 were due to the resolution of our 2006-2009 tax years. Expiration of statutes of limitations during the years ended December 31, 2019 and 2017 relate to foreign tax returns. Expiration of statutes of limitations during the year ended December 31, 2018 relate to state and foreign tax returns. The total amount of unrecognized tax benefits including interest and penalties at December 31, 2018 and 2017 , that would affect the Company’s effective tax rate if recognized was $0.5 million and $1.9 million , respectively. The total amount of tax benefit including interest and penalties recognized in 2019 due to lapses in statutes of limitations was $0.5 million . Arcosa accounts for interest expense and penalties related to income tax issues as income tax expense. Accordingly, interest expense and penalties associated with an uncertain tax position are included in the income tax provision. The total amount of accrued interest and penalties as of December 31, 2019 , 2018 , and 2017 was $0.0 million , $0.0 million , and $0.9 million , respectively. Income tax expense for the years ended December 31, 2019 , 2018 , and 2017 included decreases of $0.0 million , $0.9 million , and $1.5 million , respectively, with regard to interest expense and penalties related to uncertain tax positions.

Employee Retirement Plans

Employee Retirement Plans	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Employee Retirement Plans	Employee Retirement Plans The Company sponsors defined benefit plans and defined contribution profit sharing plans that provide retirement income and death benefits for eligible employees and retirees of the Company. For periods prior to the Separation, the participation of employees of the Company in defined benefit plans sponsored by Trinity is reflected in the combined financial statements as though the Company participated in a multiemployer plan with Trinity. The assets and liabilities of the defined benefit plans were retained by Trinity. Prior to the Separation, the expenses of these benefit plans were allocated to Arcosa based on a review of personnel and personnel costs by business unit and funded through intercompany transactions with Trinity. A proportionate share of the cost is reflected in the combined financial statements. In connection with the Separation, certain defined contribution profit sharing plans were separated into standalone plans for Arcosa and Trinity. Total employee retirement plan expense, which includes related administrative expenses, is as follows: Year Ended December 31, 2019 2018 2017 (in millions) Defined contribution plans $ 8.5 $ 8.3 $ 6.9 Multiemployer plan 1.8 2.1 2.1 $ 10.3 $ 10.4 $ 9.0 Defined Contribution Plans Established under Internal Revenue Code Section 401(k), the Arcosa, Inc. Profit Sharing Plan ("401(k) Plan") is a defined contribution plan available to all eligible employees. Participants in the 401(k) Plan are eligible to receive future retirement benefits through a company-funded annual retirement contribution and company match, both of which are discretionary, requiring board approval, and are made annually, in the year following service, with the investment of the funds directed by the participants. The Company also sponsors a fully‑funded, non-qualified deferred compensation plan. The invested assets and related liabilities of these participants were approximately $3.9 million and $2.8 million at December 31, 2019 and 2018 , respectively, which are included in “Other assets” and “Other liabilities” on the Consolidated Balance Sheets. There were no distributions from the Company’s non-qualified deferred compensation plan to participants for the years ended December 31, 2019 and 2018 . Multiemployer Plan The Company contributes to a multiemployer defined benefit pension plan under the terms of a collective-bargaining agreement that covers certain union-represented employees at one of the facilities of Meyer Utility Structures, a subsidiary of Arcosa. The risks of participating in a multiemployer plan are different from a single-employer plan in the following aspects: • Assets contributed to a multiemployer plan by one employer may be used to provide benefits to employees of other participating employers. • If a participating employer stops contributing to a multiemployer plan, the unfunded obligations of the plan may be borne by the remaining participating employers. • If the Company chooses to stop participating in the multiemployer plan, the Company may be required to pay the plan an amount based on the underfunded status of the plan, referred to as a withdrawal liability. Our participation in the multiemployer plan for the year ended December 31, 2019 is outlined in the table below. The Pension Protection Act ("PPA") zone status at December 31, 2019 and 2018 is as of the plan years beginning January 1, 2019 and 2018 , respectively, and is obtained from the multiemployer plan's regulatory filings available in the public domain and certified by the plan's actuary. Among other factors, plans in the yellow zone are less than 80% funded while plans in the red zone are less than 65% funded. Federal law requires that plans classified in the yellow or red zones adopt a funding improvement plan or a rehabilitation plan in order to improve the financial health of the plan. The Company's contributions to the multiemployer plan were less than 5% of total contributions to the plan. The last column in the table lists the expiration date of the collective bargaining agreement to which the plan is subject. PPA Zone Status Contributions for Year Ended December 31, Pension Fund Employer Identification Number 2019 2018 Rehabilitation plan status 2019 2018 2017 Surcharge imposed Expiration date of collective bargaining agreement (in millions) Boilermaker-Blacksmith National Pension Trust 48-6168020 Red Yellow Implemented $ 1.8 $ 2.1 $ 1.9 Yes June 30, 2022 Employer contributions to the multiemployer plan for the year ending December 31, 2020 are expected to be $1.8 million . ACG Pension Plan In connection with the acquisition of ACG in December 2018, the Company assumed the assets and liabilities related to a defined benefit pension plan. As of December 31, 2019 , the plan assets totaled $3.2 million and the projected benefit obligation totaled $3.1 million , for a net over funded status of $0.1 million , which is included in other assets on the Consolidated Balance Sheet. The net pension expense for the year ended December 31, 2019 was not significant. Employer contributions for the ACG pension plan for the year ending December 31, 2020 are not expected to be significant.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Changes in accumulated other comprehensive loss for the twelve months ended December 31, 2019 , December 31, 2018 , and December 31, 2017 are as follows: Currency translation adjustments Unrealized loss on derivative financial instruments Accumulated Other Comprehensive Loss (in millions) Balances at December 31, 2016 $ (18.4 ) $ — $ (18.4 ) Other comprehensive loss, net of tax, before reclassifications (1.4 ) — (1.4 ) Other comprehensive loss (1.4 ) — (1.4 ) Balances at December 31, 2017 (19.8 ) — (19.8 ) Other comprehensive loss, net of tax, before reclassifications — (0.9 ) (0.9 ) Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $0.0, $0.0, and $0.0 3.0 — 3.0 Other comprehensive income (loss) 3.0 (0.9 ) 2.1 Balances at December 31, 2018 (16.8 ) (0.9 ) (17.7 ) Other comprehensive income (loss), net of tax, before reclassifications 0.5 (2.8 ) (2.3 ) Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $0.0, $0.1, and $0.1 — 0.3 0.3 Other comprehensive income (loss) 0.5 (2.5 ) (2.0 ) Balances at December 31, 2019 $ (16.3 ) $ (3.4 ) $ (19.7 ) Reclassifications of unrealized before-tax losses on derivative financial instruments are included in interest expense in the Consolidated and Combined Statements of Operations. The reclassifications of unrealized before-tax losses on currency translation adjustments for the year ended December 31, 2018

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Prior to the Separation, Arcosa employees participated in Trinity's equity incentive plans, including equity awards of restricted stock, restricted stock units, and performance-based restricted stock units in respect of Trinity common shares. For periods prior to the Separation, Arcosa's Consolidated and Combined Financial Statements reflect compensation expense for these stock-based plans associated with the portion of Trinity's equity incentive plans in which Arcosa employees participated. Following the Separation, outstanding awards granted to Arcosa employees under Trinity's equity incentive plans were converted based on either the shareholder method or the concentration method. The shares or units converted using the shareholder method resulted in employees retaining their restricted shares or units in Trinity common stock and receiving one restricted Arcosa share or unit for every three restricted Trinity shares or units. The units converted using the concentration method were fully converted into Arcosa units using a conversion ratio based on the Volume Weighted Average Prices ("VWAP") of Trinity common stock for the 5 days prior to the Separation divided by the VWAP of Arcosa common stock for the 5 days following the Separation. The Arcosa units continue to vest in accordance with their original vesting schedules. There was no significant incremental stock-based compensation expense recorded as a result of the equity award conversions. In connection with the Separation, effective November 1, 2018, the Board adopted and Trinity, in its capacity as sole shareholder of Arcosa prior to the Separation, approved, the Arcosa Inc. 2018 Stock Option and Incentive Plan (the "Plan"). The Plan provides for the grant of equity awards, including stock options, restricted stock, restricted stock units, performance shares, and other performance-based awards, to our directors, officers, and employees. The maximum number of shares of Arcosa common stock that may be issued under the Plan is 4.8 million shares, which includes the shares granted under the Trinity equity incentive plans that were converted and assumed by Arcosa as a result of the Separation. At December 31, 2019 , we had 2.4 million shares available for grant. Any equity awards that have been granted under the Plan that are subsequently forfeited, canceled, or tendered to satisfy tax withholding obligations are added back to the shares available for grant. The cost of employee services received in exchange for awards of equity instruments is referred to as share-based payments and is based on the grant date fair-value of those awards. Stock-based compensation includes compensation expense, recognized over the applicable vesting periods, for share-based awards. The Company recognizes compensation expense for both the Arcosa awards and Trinity awards held by our employees. Stock-based compensation totaled $14.6 million , $9.9 million , and $9.0 million for the years ended December 31, 2019 , 2018 , and 2017 , respectively. The income tax benefit related to stock-based compensation expense was $2.7 million , $2.6 million , and $4.6 million for the years ended December 31, 2019 , 2018 , and 2017 , respectively. Equity Awards Equity awards outstanding as of December 31, 2019 consist of restricted stock, restricted stock units, and performance units and generally vest for periods ranging from 1 to 15 years from the date of grant. Certain equity awards vest in their entirety upon the employee's retirement from the Company and may take into consideration the employee's age and years of service to the Company, as defined more specifically in the Company's award agreements. Equity awards granted to non-employee directors under the Plan generally vest one year from the grant date and are released at that time, in the case of restricted stock, or upon completion of the directors' service to the Company, in the case of restricted stock units. Expense related to equity awards issued to eligible employees and directors under the Plan is recognized ratably over the vesting period or to the date on which retirement eligibility is achieved, if shorter. Performance units vest and settle in shares of our common stock following the end of a three-year performance period contingent upon the achievement of specific performance goals during the performance period and certification by the Human Resources Committee of the Board of the achievement of the performance goals. Performance units are granted to employees based upon a target level of performance; however, depending upon the achievement of the performance goals during the performance period, performance units may be issued at an amount between 0% and 200% of the target level. Expense related to performance units is recognized ratably over the vesting period. Forfeitures are recognized as reduction to expense in the period in which they occur. The activity for equity awards held by Arcosa employees for the year ended December 31, 2019 was as follows: Trinity Equity Awards Held by Arcosa Employees Arcosa Equity Awards Held by Arcosa Employees Weighted Average Grant-Date Equity awards outstanding at December 31, 2018 1,156,959 1,066,165 $ 21.12 Granted — 417,008 36.21 Vested (293,239 ) (198,762 ) 20.17 Forfeited (39,735 ) (59,743 ) 25.60 Equity awards outstanding at December 31, 2019 823,985 1,224,668 $ 24.20 At December 31, 2019 , unrecognized compensation expense related to equity awards totaled $24.6 million which will be recognized over a weighted average period of 2.9 years . The total vesting-date fair value of shares vested and released during the year ended December 31, 2019 was $13.3 million .

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share Basic earnings per common share is computed by dividing net income remaining after allocation to unvested restricted shares, which includes unvested restricted shares of Arcosa stock held by employees of the Former Parent, by the weighted average number of basic common shares outstanding for the period. Except when the effect would be antidilutive, the calculation of diluted earnings per common share includes the weighted average net impact of nonparticipating unvested restricted shares. For periods prior to the Separation, the denominator for basic and diluted net income per share was calculated using the 48.8 million shares of common stock outstanding immediately following the Separation. Total weighted average restricted shares were 1.6 million shares, 0.3 million shares, and 0.0 million shares, for the years ended December 31, 2019 , 2018 , and 2017 , respectively. There were no weighted average restricted shares prior to the Separation. The computation of basic and diluted earnings per share follows. Year Ended December 31, 2019 (in millions, except per share amounts) Income (Loss) Average Shares EPS Net income $ 113.3 Unvested restricted share participation (1.1 ) Net income per common share – basic 112.2 47.9 $ 2.34 Effect of dilutive securities: Nonparticipating unvested restricted shares — 0.5 Net income per common share – diluted $ 112.2 48.4 $ 2.32 Year Ended December 31, 2018 (in millions, except per share amounts) Income (Loss) Average Shares EPS Net income $ 75.7 Unvested restricted share participation (0.2 ) Net income per common share – basic 75.5 48.8 $ 1.55 Effect of dilutive securities: Nonparticipating unvested restricted shares — 0.1 Net income per common share – diluted $ 75.5 48.9 $ 1.54 Year Ended December 31, 2017 (in millions, except per share amounts) Income (Loss) Average Shares EPS Net income $ 89.7 Unvested restricted share participation — Net income per common share – basic 89.7 48.8 $ 1.84 Effect of dilutive securities: Nonparticipating unvested restricted shares — — Net income per common share – diluted $ 89.7 48.8 $ 1.84

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company is involved in claims and lawsuits incidental to our business arising from various matters including commercial disputes, alleged product defect and/or warranty claims, intellectual property matters, personal injury claims, environmental issues, employment and/or workplace-related matters, and various governmental regulations. At December 31, 2019 , the range of reasonably possible losses for such matters, taking into consideration our rights in indemnity and recourse to third parties, is $1.1 million to $4.6 million . The Company evaluates its exposure to such claims and suits periodically and establishes accruals for these contingencies when probable losses can be reasonably estimated. At December 31, 2019 , total accruals of $3.6 million , including environmental matters described below, are included in accrued liabilities in the accompanying Consolidated Balance Sheet. The Company believes any additional liability from such claims and suits would not be material to its financial position or results of operations. Arcosa is subject to remedial orders and federal, state, local, and foreign laws and regulations relating to the environment. The Company has reserved $1.4 million as of December 31, 2019 , included in our total accruals of $3.6 million discussed above, to cover our probable and estimable liabilities with respect to the investigations, assessments, and remedial responses to such matters, taking into account currently available information and our contractual rights to indemnification and recourse to third parties. On July 22, 2019, the Company was served with a breach of contract lawsuit filed by Thomas & Betts Corporation (“T&B”) against the Company and its wholly-owned subsidiary, Trinity Meyer Utility Structures, LLC, now known as Meyer Utility Structures, LLC (“Meyer”), in the Supreme Court of the State of New York, New York County. T&B’s claims relate to responsibility for alleged product warranty claims pursuant to the terms of the Asset Purchase Agreement, dated June 24, 2014, entered into by and between T&B and Meyer (the “APA”) with respect to Meyer’s purchase of certain assets of T&B’s utility structure business. The Company and Meyer subsequently removed the litigation to federal court. The case is currently pending under Case No. 1:19-cv-07829-PAE; Thomas & Betts Corporation, now known as, ABB Installation Products, Inc., Plaintiff, v. Trinity Meyer Utility Structures, LLC, formerly known as McKinley 2014 Acquisition, LLC, and Arcosa, Inc., Defendants; In the United States District Court for the Southern District of New York. The Company and Meyer have filed a motion to dismiss T&B’s claims, and an Answer and Counterclaims against T&B. We intend to vigorously defend ourselves in this matter. Based on the facts and circumstances currently known to the Company, (i) we cannot determine that a loss is probable at this time, and therefore no accrual has been included in the accompanying consolidated financial statements; and (ii) a possible loss is not reasonably estimable. Estimates of liability arising from future proceedings, assessments, or remediation are inherently imprecise. Accordingly, there can be no assurance that we will not become involved in future litigation or other proceedings involving the environment or, if we are found to be responsible or liable in any such litigation or proceeding, that such costs would not be material to the Company. Other commitments Non-cancelable purchase obligations amounted to $168.9 million as of December 31, 2019 , of which $110.1 million is for the purchase of raw materials and components, primarily by the Energy Equipment and Transportation Products Groups.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) Three Months Ended March 31, 2019 June 30, 2019 September 30, 2019 December 31, 2019 (in millions except per share data) Revenues $ 410.9 $ 434.1 $ 445.0 $ 446.9 Operating costs: Cost of revenues 332.8 345.7 356.7 369.3 Selling, general, and administrative expenses 40.8 46.1 45.5 47.1 Operating profit 37.3 42.3 42.8 30.5 Income before income taxes 35.6 40.8 41.9 28.5 Provision for income taxes 7.9 9.0 9.2 7.4 Net income $ 27.7 $ 31.8 $ 32.7 $ 21.1 Net income per common share: Basic $ 0.57 $ 0.66 $ 0.68 $ 0.44 Diluted $ 0.56 $ 0.65 $ 0.67 $ 0.43 Three Months Ended March 31, 2018 June 30, 2018 September 30, 2018 December 31, 2018 (in millions except per share data) Revenues $ 354.4 $ 353.0 $ 378.6 $ 374.4 Operating costs: Cost of revenues 285.6 283.0 308.9 310.9 Selling, general, and administrative expenses 37.6 39.4 40.1 36.8 Impairment charge — — 23.2 — Operating profit 31.2 30.6 6.4 26.7 Income before income taxes 30.2 29.4 6.6 28.8 Provision for income taxes 8.0 6.8 3.4 1.1 Net income $ 22.2 $ 22.6 $ 3.2 $ 27.7 Net income per common share (1) : Basic $ 0.45 $ 0.46 $ 0.07 $ 0.56 Diluted $ 0.45 $ 0.46 $ 0.07 $ 0.56 (1) For periods prior to the Separation, the denominator for basic and diluted net income per common share was calculated using the 48.8 million shares of common stock outstanding immediately following the Separation.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation On November 1, 2018, Arcosa, Inc. and its consolidated subsidiaries (“Arcosa,” the “Company,” “we,” or “our”) became an independent publicly-traded company as a result of the distribution by Trinity Industries, Inc. (“Trinity” or "Former Parent") of 100% of the outstanding shares of Arcosa, Inc. to Trinity’s stockholders (the “Separation”). Trinity stockholders received one share of Arcosa, Inc. common stock for every three shares of Trinity common stock held as of 5:00 p.m. local New York City time on October 17, 2018, the record date for the distribution. The transaction was structured to be tax-free to both Trinity and Arcosa stockholders for U.S. federal income tax purposes. The accompanying Consolidated and Combined Financial Statements present our historical financial position, results of operations, comprehensive income/loss, and cash flows in accordance with accounting principles generally accepted in the U.S. (“GAAP”). The combined financial statements for periods prior to the Separation were derived from Trinity’s consolidated financial statements and accounting records and prepared in accordance with GAAP for the preparation of carved-out combined financial statements. Through the date of the Separation, all revenues and costs as well as assets and liabilities directly associated with Arcosa have been included in the combined financial statements. Prior to the Separation, the combined financial statements also included allocations of certain selling, general, and administrative expenses provided by Trinity to Arcosa and allocations of related assets, liabilities, and the Former Parent’s net investment, as applicable. The allocations were determined on a reasonable basis; however, the amounts are not necessarily representative of the amounts that would have been reflected in the financial statements had the Company been an entity that operated independently of Trinity during the applicable periods. Following the Separation, the consolidated financial statements include the accounts of the Company and its subsidiaries and no longer include any allocations from Trinity.
Relationship with Former Parent and Related Entities	Relationship with Former Parent and Related Entities Prior to the Separation, Arcosa was managed and operated in the normal course of business with other business units of Trinity. The accompanying combined financial results for periods prior to the Separation include sales and purchase transactions with Trinity and its subsidiaries in addition to certain shared costs which have been allocated to Arcosa and reflected as expenses in the Combined Statements of Operations. Transactions and allocations between Trinity and Arcosa are reflected in equity in the Combined Balance Sheets as Former Parent's net investment and in the Combined Statements of Cash Flows as a financing activity in Net transfers from/(to) Former Parent and affiliates. All transactions and allocations between Trinity and Arcosa prior to the Separation have been deemed paid between the parties, in cash, in the period in which the transaction or allocation was recorded in the Combined Financial Statements. Disbursements and cash receipts were made through centralized accounts payable and cash collection systems, respectively, which were operated by Trinity. As cash was disbursed and received by Trinity, it was accounted for by Arcosa through the Former Parent's net investment account. Allocations of current income taxes receivable or payable prior to the Separation were deemed to have been remitted to Arcosa or Trinity, respectively, in cash, in the period to which the receivable or payable applies. Corporate Costs/Allocations The combined financial results include an allocation of costs related to certain corporate functions incurred by Trinity for services that are provided to or on behalf of Arcosa. Corporate costs have been allocated to Arcosa using methods management believes are consistent and reasonable. Such cost allocations to Arcosa consist of (1) shared service charges and (2) corporate overhead costs. Shared service charges consist of monthly charges to each Trinity business unit for certain corporate functions such as information technology, human resources, and legal based on usage rates and activity units. Corporate overhead costs consist of costs not previously allocated to Trinity's business units and were allocated to Arcosa based on an analysis of each cost function and the relative benefits received by Arcosa for each of the periods. Corporate overhead costs allocated to Arcosa prior to the Separation totaled $26.0 million and $39.3 million for the ten months ended October 31, 2018 and the year ended December 31, 2017 , respectively. Corporate overhead costs are included in selling, general, and administrative expenses in the accompanying Consolidated and Combined Statements of Operations. Also see Note 4 Segment Information. The Consolidated and Combined Financial Statements of Arcosa for the years ended December 31, 2018 and 2017 may not include all of the actual expenses that would have been incurred had we operated as a standalone company during the periods presented and may not reflect our combined results of operations, financial position, and cash flows had we operated as a standalone company during the periods presented. Actual costs that would have been incurred if we had operated as a standalone company would depend on multiple factors, including organizational structure and strategic decisions made in various areas, including information technology and infrastructure. We also may incur additional costs associated with being a standalone, independent, publicly-traded company that were not included in the expense allocations and, therefore, would result in additional costs that are not reflected in our historical results of operations, financial position, and cash flows. Other Transactions with Trinity Businesses For the years ended December 31, 2018 and 2017 , the Company had sales to Trinity businesses of $160.3 million and $148.3 million , respectively, and purchases from Trinity businesses of $44.5 million and $53.2 million , respectively. Subsequent to the Separation, Trinity is no longer considered a related entity.
Stockholders' Equity	Stockholders' Equity In December 2018 , the Company’s Board of Directors (the "Board") authorized a $50 million share repurchase program effective December 5, 2018 through December 31, 2020 . For the year ended December 31, 2019 , Company repurchased 361,442 shares at a cost of $11.0 million . As of December 31, 2019 , the Company had a remaining authorization of $36.0 million under the program. Prior to the Separation, the Company filed its Restated Certificate of Incorporation which authorizes the issuance of 200 million shares of common stock at a par value of $0.01 per share.
Revenue Recognition	Revenue Recognition Revenue is measured based on the allocation of the transaction price in a contract to satisfied performance obligations. The transaction price does not include any amounts collected on behalf of third parties. The Company recognizes revenue when it satisfies a performance obligation by transferring control over a product or service to a customer. The following is a description of principal activities from which the Company generates its revenue, separated by reportable segments. Payments for our products and services are generally due within normal commercial terms. For a further discussion regarding the Company’s reportable segments, see Note 4 Segment Information. Construction Products Group The Construction Products Group recognizes revenue when the customer has accepted the product and legal title of the product has passed to the customer. Energy Equipment Group Within the Energy Equipment Group, revenue is recognized for our wind tower, certain utility structure, and certain storage tank product lines over time as the products are manufactured using an input approach based on the costs incurred relative to the total estimated costs of production. We recognize revenue over time for these products as they are highly customized to the needs of an individual customer resulting in no alternative use to the Company if not purchased by the customer after the contract is executed, and we have the right to bill the customer for our work performed to date plus at least a reasonable profit margin for work performed. As of December 31, 2019 and 2018 , we had a contract asset of $50.8 million and $44.0 million , respectively, which is included in receivables, net of allowance, within the Consolidated Balance Sheets. For all other products, revenue is recognized when the customer has accepted the product and legal title of the product has passed to the customer. Transportation Products Group The Transportation Products Group recognizes revenue when the customer has accepted the product and legal title of the product has passed to the customer. Unsatisfied Performance Obligations The following table includes estimated revenue expected to be recognized in future periods related to performance obligations that are unsatisfied or partially satisfied as of December 31, 2019 and the percentage of the outstanding performance obligations as of December 31, 2019 expected to be delivered during 2020 : Unsatisfied performance obligations at December 31, 2019 Total Percent expected to be delivered in 2020 (in millions) Energy Equipment Group: Wind towers and utility structures $ 596.8 86.0 % Other $ 36.2 100.0 % Transportation Products Group: Inland barges $ 346.9 100.0 % The remainder of the unsatisfied performance obligations for wind towers and utility structures are expected to be delivered during 2021 .
Income Taxes	Income Taxes The liability method is used to account for income taxes. Deferred income taxes represent the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Valuation allowances reduce deferred tax assets to an amount that will more likely than not be realized. The Company regularly evaluates the likelihood of realization of tax benefits derived from positions it has taken in various federal and state filings after consideration of all relevant facts, circumstances, and available information. For those tax positions that are deemed more likely than not to be sustained, the Company recognizes the benefit it believes is cumulatively greater than 50% likely to be realized. To the extent the Company were to prevail in matters for which accruals have been established or be required to pay amounts in excess of recorded reserves, the effective tax rate in a given financial statement period could be materially impacted. Prior to the Separation, the Company’s operating results were included in the Former Parent’s various consolidated U.S. federal and state income tax returns, as well as non-U.S. tax filings. In the Company’s Combined Financial Statements for the periods prior to the Separation, income tax expense and deferred tax balances have been recorded as if the Company filed tax returns on a standalone basis separate from the Former Parent. The separate return method applies the accounting guidance for income taxes to the standalone financial statements as if the Company was a separate taxpayer and a standalone enterprise for the periods presented.
Financial Instruments, Cash and Cash Equivalents	Financial Instruments The Company considers all highly liquid debt instruments to be cash and cash equivalents if purchased with a maturity of three months
Financial Instruments, Concentration of Credit Risk	Financial instruments that potentially subject the Company to a concentration of credit risk are primarily cash investments and receivables. The Company places its cash investments in bank deposits and highly-rated money market funds, and its investment policy limits the amount of credit exposure to any one commercial issuer. We seek to limit concentrations of credit risk with respect to receivables with control procedures that monitor the credit worthiness of customers, together with the large number of customers in the Company's customer base and their dispersion across different industries and geographic areas. As receivables are generally unsecured, the Company maintains an allowance for doubtful accounts based upon the expected collectibility of all receivables. Receivable balances determined to be uncollectible are charged against the allowance. To accelerate the conversion to cash, the Company may sell a portion of its trade receivables to a third party. The Company has no continuing involvement or recourse related to these receivables once they are sold, and the impact of these transactions in the Company's Consolidated Statements of Operations for the year ended December 31, 2019 was not significant. The carrying values of cash, receivables, and accounts payable are considered to be representative of their respective fair values.
Inventories	Inventories Inventories are valued at the lower of cost or net realizable value. Cost is determined principally on the first in first out method. The value of inventory is adjusted for damaged, obsolete, excess, or slow-moving inventory. Work in process and finished goods include material, labor, and overhead. During the year ended December 31, 2018, the Company recorded a $6.1 million write-off on finished goods inventory related to an order for a single customer in our utility structures business.
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment are stated at cost and depreciated or depleted over their estimated useful lives, primarily using the straight-line method. The estimated useful lives are: buildings and improvements - 3 to 30 years ; leasehold improvements - the lesser of the term of the lease or 11 years ; machinery and equipment - 2 to 10 years ; and information systems hardware and software - 2 to 5 years . Depletion of mineral reserves is calculated based on estimated proven and probable reserves using the units-of-production method on a quarry-by-quarry basis. The costs of ordinary maintenance and repair are charged to operating costs as incurred.
Long-lived Assets	Long-lived Assets The Company periodically evaluates the carrying value of long-lived assets to be held and used for potential impairment. The carrying value of long-lived assets to be held and used is considered impaired only when the carrying value is not recoverable through undiscounted future cash flows and the fair value of the assets is less than their carrying value. Fair value is determined primarily using the anticipated cash flows discounted at a rate commensurate with the risks involved or market quotes as available. Impairment losses on long-lived assets held for sale are determined in a similar manner, except that fair values are reduced by the estimated cost to dispose of the assets. See Note 2 Acquisitions and Divestitures for discussion of the impairment charge recorded during the year ended December 31, 2018 on businesses that were subsequently divested. Based on the Company's evaluations, no additional impairment charges were determined to be necessary as of December 31, 2019 and December 31, 2017
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill is required to be tested for impairment annually, or on an interim basis whenever events or circumstances change indicating that the carrying amount of the goodwill might be impaired. The quantitative goodwill impairment test is a two-step process with step one requiring the comparison of the reporting unit's estimated fair value with the carrying amount of its net assets. If necessary, step two of the impairment test determines the amount of goodwill impairment to be recorded when the reporting unit's recorded net assets exceed its fair value. Impairment is assessed at the “reporting unit” level by applying a fair value-based test for each unit with recorded goodwill. The estimates and judgments that most significantly affect the fair value calculations are assumptions, consisting of level three inputs, related to revenue and operating profit growth, discount rates, and exit multiples. As of December 31, 2019 and 2018 , the Company's annual impairment test of goodwill was completed at the reporting unit level and no impairment charges were determined to be necessary. The net book value of intangible assets totaled $51.7 million and $55.2 million as of December 31, 2019 and 2018 , respectively, and included $34.1 million not subject to amortization related to an acquired trademark. The remaining intangible assets with a gross cost of $44.6 million as of December 31, 2019 and 2018 , are amortized over their estimated useful lives ranging from 1 to 12 years , and primarily relate to acquired customer relationships. Total amortization expense from intangible assets was $3.4 million , $4.7 million , and $5.0 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. Intangible assets were evaluated for potential impairment as of December 31, 2019 and 2018
Insurance	Workers ’ Compensation The Company is effectively self-insured for workers ’ compensation claims. A third party administrator is used to process claims. We accrue our workers' compensation liability based upon independent actuarial studies.
Warranties	Warranties The Company provides various express, limited product warranties that generally range from 1 to 5 years depending on the product. The warranty costs are estimated using a two-step approach. First, an engineering estimate is made for the cost of all claims that have been asserted by customers. Second, based on historical, accepted claims experience, a cost is accrued for all products still within a warranty period for which no claims have been filed. The Company provides for the estimated cost of product warranties at the time revenue is recognized related to products covered by warranties and assesses the adequacy of the resulting reserves on a quarterly basis. As of December 31, 2019 and 2018 , the Company's accrual for warranty costs was $2.6 million and $2.9 million , respectively, which is included in accrued liabilities within the Consolidated Balance Sheets.
Derivatives Instruments	Derivative Instruments
Foreign Currency Translation	Foreign Currency Translation Certain operations outside the U.S. prepare financial statements in currencies other than the U.S. dollar. The income statement amounts are translated at average exchange rates for the year, while the assets and liabilities are translated at year-end exchange rates. Translation adjustments are accumulated as a separate component of stockholders' equity and other comprehensive income. The functional currency of our Mexico operations is considered to be the U.S. dollar. The functional currency of our Canadian operations is considered to be the Canadian dollar.
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) Other comprehensive income (loss) consists of foreign currency translation adjustments and the effective unrealized gains and losses on the Company's derivative financial instruments, the sum of which, along with net income, constitutes comprehensive net income (loss). See Note 12 Accumulated Other Comprehensive Loss. All components are shown net of tax.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently adopted accounting pronouncements Effective as of January 1, 2018, the Company adopted Accounting Standards Update No. 2014-09, “Revenue from Contracts with Customers,” (“ASU 2014-09”), which provides common revenue recognition guidance for GAAP. Under ASU 2014-09, an entity recognizes revenue when it transfers promised goods or services to customers in an amount that reflects what it expects to receive in exchange for the goods or services. It also requires additional detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenues and cash flows arising from contracts with customers. The Company applied ASU 2014-09 to all contracts that were not complete as of January 1, 2018 using the modified retrospective method of adoption, resulting in a reduction to Former Parent's Net Investment of $4.0 million , net of tax, as of January 1, 2018 related to the cumulative effect of applying this standard. Therefore, the comparative information for the year ended December 31, 2017 has not been adjusted and continue to be reported under ASC Topic 605. The primary impact of adopting the standard is a change in the timing of revenue recognition for our wind towers, certain utility structures, and certain storage tank product lines within our Energy Equipment Group. Previously, the Company recognized revenue when the product was delivered. Under ASU 2014-09, revenue is recognized over time as the products are manufactured. Revenue recognition policies in our other business segments remain substantially unchanged. Effective as of January 1, 2019, the Company adopted Accounting Standards Update No. 2016-02, “Leases”, (“ASU 2016-02”), which amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets and making targeted changes to lessor accounting. The Company elected to use the optional transition method that allows the Company to apply the provisions of the standard at the effective date without adjusting the comparative prior periods. In addition, we elected the package of practical expedients permitted under the transition guidance within the new standard which allowed us to carry forward the historical lease classification. The cumulative effect of adopting the standard on the opening balance of retained earnings was not significant. The primary impact of adopting the standard was the recognition of a right-of-use asset of $23.7 million and corresponding lease liability of $27.5 million for our operating leases included in other assets and other liabilities, respectively, on the Consolidated Balance Sheet. See Note 8 Leases for further discussion. The Company has implemented processes and a lease accounting system to ensure adequate internal controls were in place to assess our contracts and enable proper accounting and reporting of financial information upon adoption. Recently issued accounting pronouncements not adopted as of December 31, 2019 In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2016-13, “Financial Instruments - Credit Losses”, (“ASU 2016-13”), which amends the existing accounting guidance for recognizing credit losses on financial assets and certain other instruments not measured at fair value through net income, including financial assets measured at amortized cost, such as trade receivables and contract assets. ASU 2016-13 replaces the existing incurred loss impairment model with an expected credit loss model that requires consideration of a broader range of information to estimate expected credit losses over the lifetime of the asset. The new guidance is expected to result in earlier recognition of credit losses. ASU 2016-13 will become effective for public companies during interim and annual reporting periods beginning after December 15, 2019, with early adoption permitted. The Company will adopt the new standard on January 1, 2020 and does not expect the adoption of the guidance to have a material impact on our consolidated financial statements. In December 2019, the FASB issued Accounting Standards Updated No. 2019-12, “Simplifying the Accounting for Income Taxes”, (“ASU 2019-12”), which simplifies the accounting for income taxes by removing certain exceptions to the general principles for income taxes. ASU 2019-12 will become effective for public companies during interim and annual reporting periods beginning after December 15, 2020, with early adoption permitted. We are currently evaluating the impact of adoption on our consolidated financial statements.
Management's Estimates	Management's Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Reclassifications	Reclassifications Certain prior year balances have been reclassified in the Consolidated and Combined Financial Statements to conform with the 2019 presentation.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Unsatisfied Performance Obligations	Unsatisfied Performance Obligations The following table includes estimated revenue expected to be recognized in future periods related to performance obligations that are unsatisfied or partially satisfied as of December 31, 2019 and the percentage of the outstanding performance obligations as of December 31, 2019 expected to be delivered during 2020 : Unsatisfied performance obligations at December 31, 2019 Total Percent expected to be delivered in 2020 (in millions) Energy Equipment Group: Wind towers and utility structures $ 596.8 86.0 % Other $ 36.2 100.0 % Transportation Products Group: Inland barges $ 346.9 100.0 %

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	12 Months Ended
	Dec. 31, 2019
Business Acquisition [Line Items]
Acquisition and divestiture activity	The Company's acquisition and divestiture activities are summarized below: Year Ended December 31, 2019 2018 2017 (in millions) Acquisitions: Purchase price $ 39.2 $ 334.1 $ 63.0 Net cash paid $ 32.9 $ 333.2 $ 47.5 Goodwill recorded $ 12.6 $ 120.9 $ 25.0
ACG Materials
Business Acquisition [Line Items]
Final purchase price allocation	The following table represents our final purchase price allocation (in millions): Accounts receivable $ 23.8 Inventories 12.5 Property, plant, and equipment 77.8 Mineral reserves 137.3 Goodwill 105.5 Other assets 6.3 Accounts payable (10.2 ) Accrued and other liabilities (14.5 ) Capital lease obligations (8.3 ) Deferred income taxes (21.1 ) Total net assets acquired $ 309.1
Pro-forma consolidated and combined operating results	The following table represents the unaudited pro-forma consolidated operating results of the Company as if the ACG acquisition had been completed on January 1, 2017. The unaudited pro-forma information makes certain adjustments to depreciation, depletion, and amortization expense to reflect the fair value recognized in the purchase price allocation, as well as to align ACG's capital structure and debt financing with that of the Company at the acquisition date. As a measure of unaudited pro-forma earnings, we have presented income before income taxes because our effective tax rates for 2018 and 2017 were impacted by one-time effects of the Act that would be impracticable to calculate for ACG. The unaudited pro-forma information should not be considered indicative of the results that would have occurred if the acquisition had been completed on January 1, 2017, nor is such unaudited pro-forma information necessarily indicative of future results. Year Ended December 31, 2018 Year Ended December 31, 2017 (in millions) Revenues $ 1,604.1 $ 1,594.4 Income before income taxes $ 97.6 $ 133.6

Fair Value Accounting (Tables)

Fair Value Accounting (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value on recurring basis	Assets and liabilities measured at fair value on a recurring basis are summarized below: Fair Value Measurement as of December 31, 2019 Level 1 Level 2 Level 3 Total (in millions) Assets: Cash equivalents $ 155.3 $ — $ — $ 155.3 Total assets $ 155.3 $ — $ — $ 155.3 Liabilities: Interest rate hedge (1) $ — $ 4.3 $ — $ 4.3 Contingent consideration (2) — — 6.4 6.4 Total liabilities $ — $ 4.3 $ 6.4 $ 10.7 Fair Value Measurement as of December 31, 2018 Level 1 Level 2 Level 3 Total (in millions) Assets: Cash equivalents $ 30.0 $ — $ — $ 30.0 Total assets $ 30.0 $ — $ — $ 30.0 Liabilities: Interest rate hedge (1) $ — $ 1.2 $ — $ 1.2 Total liabilities $ — $ 1.2 $ — $ 1.2 (1) Included in other liabilities on the Consolidated Balance Sheet. (2) Current portion included in accrued liabilities and non-current portion included in other liabilities on the Consolidated Balance Sheets.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Financial information for segments	Revenues Operating Profit (Loss) Assets Depreciation, Depletion, & Amortization Capital Expenditures Construction aggregates $ 364.7 Other 75.0 Construction Products Group 439.7 $ 52.7 $ 785.0 $ 38.0 $ 30.2 Wind towers and utility structures 625.4 Other 211.2 Energy Equipment Group 836.6 100.7 934.9 27.9 25.0 Inland barges 293.9 Steel components 171.8 Transportation Products Group 465.7 46.8 316.5 16.3 21.8 Segment Totals before Eliminations and Corporate 1,742.0 200.2 2,036.4 82.2 77.0 Corporate — (47.3 ) 266.1 3.6 8.4 Eliminations (5.1 ) — — — — Consolidated Total $ 1,736.9 $ 152.9 $ 2,302.5 $ 85.8 $ 85.4 Year Ended December 31, 2018 Revenues Operating Profit (Loss) Assets Depreciation, Depletion, & Amortization Capital Expenditures Construction aggregates $ 217.9 Other 74.4 Construction Products Group 292.3 $ 50.4 $ 769.8 $ 21.9 $ 17.2 Wind towers and utility structures 582.9 Other 197.2 Energy Equipment Group 780.1 28.6 976.2 29.7 16.0 Inland barges 170.2 Steel components 221.2 Transportation Products Group 391.4 48.4 305.0 15.5 10.3 All Other — (0.1 ) — — — Segment Totals before Eliminations and Corporate 1,463.8 127.3 2,051.0 67.1 43.5 Corporate — (32.1 ) 121.2 0.5 1.3 Eliminations (3.4 ) (0.3 ) — — — Consolidated and Combined Total $ 1,460.4 $ 94.9 $ 2,172.2 $ 67.6 $ 44.8 Year Ended December 31, 2017 Revenues Operating Profit (Loss) Assets Depreciation, Depletion, & Amortization Capital Expenditures Construction aggregates $ 204.9 Other 54.0 Construction Products Group 258.9 $ 53.7 $ 391.2 $ 18.4 $ 48.9 Wind towers and utility structures 652.1 Other 192.0 Energy Equipment Group 844.1 78.4 928.8 30.2 27.7 Inland barges 157.9 Steel components 205.4 Transportation Products Group 363.3 39.0 257.5 17.1 5.8 All Other — (0.1 ) — — — Segment Totals before Eliminations and Corporate 1,466.3 171.0 1,577.5 65.7 82.4 Corporate — (39.3 ) 25.0 — — Eliminations (3.9 ) — — — — Combined Total $ 1,462.4 $ 131.7 $ 1,602.5 $ 65.7 $ 82.4
Revenues, operating profit, total assets, and long-lived assets for Mexico operations	Revenues and operating profit for our Mexico operations for the years ended December 31, 2019 , 2018 , and 2017 are presented below. Our Canadian operations were not significant in relation to the consolidated financial statements. Year Ended December 31, 2019 2018 2017 (in millions) Mexico: Revenues: External $ 110.1 $ 108.2 $ 118.2 Intercompany 88.0 82.3 62.6 $ 198.1 $ 190.5 $ 180.8 Operating profit $ 4.8 $ (11.0 ) $ 1.4 Total assets and long-lived assets for our Mexico operations as of December 31, 2019 and 2018 are presented below: Total Assets Long-Lived Assets December 31, 2019 2018 2019 2018 (in millions) Mexico $ 202.2 $ 203.8 $ 85.5 $ 85.8

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Components of property, plant, and equipment	The following table summarizes the components of property, plant, and equipment as of December 31, 2019 and 2018 . December 31, December 31, (in millions) Land (1) $ 331.4 $ 316.5 Buildings and improvements 280.5 267.5 Machinery and other 755.7 715.9 Construction in progress 38.6 28.8 1,406.2 1,328.7 Less accumulated depreciation and depletion (590.0 ) (525.7 ) $ 816.2 $ 803.0 (1) Includes depletable land of $211.0 million as of December 31, 2019 and $201.9 million as of December 31, 2018 .

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill by segment	Goodwill by segment is as follows: December 31, December 31, (in millions) Construction Products Group $ 166.2 $ 171.7 Energy Equipment Group 416.9 416.9 Transportation Products Group 38.8 26.6 $ 621.9 $ 615.2

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Components of debt	The following table summarizes the components of debt as of December 31, 2019 and December 31, 2018 : December 31, December 31, (in millions) Revolving credit facility $ 100.0 $ 180.0 Finance leases 7.3 5.5 Total debt $ 107.3 $ 185.5
Remaining principal payments under existing debt agreements	The remaining principal payments under existing debt agreements as of December 31, 2019 are as follows: 2020 2021 2022 2023 2024 Thereafter (in millions) Revolving credit facility $ — $ — $ — $ 100.0 $ — $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Operating leases	The following table presents information about the amount, timing, and uncertainty of cash flows arising from the Company's operating leases as of December 31, 2019 . December 31, 2019 (in millions) Maturity of Lease Liabilities 2020 $ 6.4 2021 4.0 2022 2.6 2023 2.0 2024 1.7 Thereafter 6.0 Total undiscounted operating lease payments 22.7 Less imputed interest (3.7 ) Present value of operating lease liabilities $ 19.0 Balance Sheet Classification Other assets $ 15.6 Accrued liabilities $ 5.5 Other liabilities 13.5 Total operating lease liabilities $ 19.0 Other Information Weighted average remaining lease term 5.8 years Weighted average discount rate 4.8 %
Prior period adoption of ASU 2016-02	Disclosures related to periods prior to adoption of ASU 2016-02 December 31, 2018 (in millions) Future Minimum Rent Expense 2019 $ 7.7 2020 5.7 2021 3.5 2022 2.3 2023 1.8 Thereafter 7.6 Total undiscounted operating lease payments $ 28.6

Other, Net (Tables)

Other, Net (Tables)	12 Months Ended
	Dec. 31, 2019
Other Income and Expenses [Abstract]
Summary of other, net (income) expense	Other, net (income) expense consists of the following items: Year Ended December 31, 2019 2018 2017 (in millions) Interest income $ (1.4 ) $ (0.4 ) $ (0.1 ) Foreign currency exchange transactions 1.5 (0.2 ) 2.2 Other (0.8 ) (0.4 ) (0.5 ) Other, net (income) expense $ (0.7 ) $ (1.0 ) $ 1.6

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Components of the provision for income taxes	The components of the provision for income taxes are as follows: Year Ended December 31, 2019 2018 2017 (in millions) Current: Federal $ 7.6 $ (5.4 ) $ 29.3 State 3.0 0.8 0.5 Foreign 5.6 1.5 0.3 Total current 16.2 (3.1 ) 30.1 Deferred: Federal: Effect of Tax Cuts and Jobs Act — (1.5 ) (6.2 ) Other 22.6 24.8 16.6 22.6 23.3 10.4 State (0.6 ) 5.4 0.9 Foreign (4.7 ) (6.3 ) (1.0 ) Total deferred 17.3 22.4 10.3 Provision $ 33.5 $ 19.3 $ 40.4
Reconciliation between the statutory U.S. Federal income tax rate and the Company's effective income tax rate	The following is a reconciliation between the statutory U.S. federal income tax rate and the Company’s effective income tax rate on income before income taxes: Year Ended December 31, 2019 2018 2017 Statutory rate 21.0 % 21.0 % 35.0 % State taxes 3.1 3.1 2.5 Domestic production activities deduction — — (2.1 ) Changes in valuation allowances and reserves (1.3 ) (1.2 ) 1.3 Changes in tax reserves (0.3 ) (1.4 ) 0.8 Effect of Tax Cuts and Jobs Act — (1.6 ) (5.0 ) Prior year true-ups (0.5 ) (0.4 ) (2.2 ) Foreign adjustments 0.6 2.4 1.8 Other, net 0.2 (1.6 ) (1.0 ) Effective rate 22.8 % 20.3 % 31.1 %
Components of deferred tax liabilities and assets	The components of deferred tax liabilities and assets are as follows: December 31, 2019 2018 (in millions) Deferred tax liabilities: Depreciation, depletion, and amortization $ 109.1 $ 103.2 Total deferred tax liabilities 109.1 103.2 Deferred tax assets: Workers compensation, pensions, and other benefits 21.6 16.2 Warranties and reserves 1.7 2.2 Tax loss carryforwards and credits 14.8 31.0 Inventory 22.7 10.8 Accrued liabilities and other 1.0 (2.7 ) Total deferred tax assets 61.8 57.5 Net deferred tax assets (liabilities) before valuation allowances (47.3 ) (45.7 ) Valuation allowances 4.8 5.7 Adjusted net deferred tax assets (liabilities) $ (52.1 ) $ (51.4 )
Change in unrecognized tax benefits	The change in unrecognized tax benefits for the years ended December 31, 2019 , 2018 , and 2017 was as follows: December 31, 2019 2018 2017 (in millions) Beginning balance $ 0.5 $ 1.3 $ 7.4 Additions for tax positions related to the current year — — — Additions for tax positions of prior years — 0.1 0.2 Reductions for tax positions of prior years — — — Settlements — — (6.0 ) Expiration of statute of limitations (0.5 ) (0.9 ) (0.3 ) Ending balance $ — $ 0.5 $ 1.3

Employee Retirement Plans (Tabl

Employee Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Total employee retirement plan expense	Total employee retirement plan expense, which includes related administrative expenses, is as follows: Year Ended December 31, 2019 2018 2017 (in millions) Defined contribution plans $ 8.5 $ 8.3 $ 6.9 Multiemployer plan 1.8 2.1 2.1 $ 10.3 $ 10.4 $ 9.0
Details of multiemployer plan	Our participation in the multiemployer plan for the year ended December 31, 2019 is outlined in the table below. The Pension Protection Act ("PPA") zone status at December 31, 2019 and 2018 is as of the plan years beginning January 1, 2019 and 2018 , respectively, and is obtained from the multiemployer plan's regulatory filings available in the public domain and certified by the plan's actuary. Among other factors, plans in the yellow zone are less than 80% funded while plans in the red zone are less than 65% funded. Federal law requires that plans classified in the yellow or red zones adopt a funding improvement plan or a rehabilitation plan in order to improve the financial health of the plan. The Company's contributions to the multiemployer plan were less than 5% of total contributions to the plan. The last column in the table lists the expiration date of the collective bargaining agreement to which the plan is subject. PPA Zone Status Contributions for Year Ended December 31, Pension Fund Employer Identification Number 2019 2018 Rehabilitation plan status 2019 2018 2017 Surcharge imposed Expiration date of collective bargaining agreement (in millions) Boilermaker-Blacksmith National Pension Trust 48-6168020 Red Yellow Implemented $ 1.8 $ 2.1 $ 1.9 Yes June 30, 2022

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Changes in accumulated other comprehensive loss	Changes in accumulated other comprehensive loss for the twelve months ended December 31, 2019 , December 31, 2018 , and December 31, 2017 are as follows: Currency translation adjustments Unrealized loss on derivative financial instruments Accumulated Other Comprehensive Loss (in millions) Balances at December 31, 2016 $ (18.4 ) $ — $ (18.4 ) Other comprehensive loss, net of tax, before reclassifications (1.4 ) — (1.4 ) Other comprehensive loss (1.4 ) — (1.4 ) Balances at December 31, 2017 (19.8 ) — (19.8 ) Other comprehensive loss, net of tax, before reclassifications — (0.9 ) (0.9 ) Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $0.0, $0.0, and $0.0 3.0 — 3.0 Other comprehensive income (loss) 3.0 (0.9 ) 2.1 Balances at December 31, 2018 (16.8 ) (0.9 ) (17.7 ) Other comprehensive income (loss), net of tax, before reclassifications 0.5 (2.8 ) (2.3 ) Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $0.0, $0.1, and $0.1 — 0.3 0.3 Other comprehensive income (loss) 0.5 (2.5 ) (2.0 ) Balances at December 31, 2019 $ (16.3 ) $ (3.4 ) $ (19.7 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of restricted stock activity	The activity for equity awards held by Arcosa employees for the year ended December 31, 2019 was as follows: Trinity Equity Awards Held by Arcosa Employees Arcosa Equity Awards Held by Arcosa Employees Weighted Average Grant-Date Equity awards outstanding at December 31, 2018 1,156,959 1,066,165 $ 21.12 Granted — 417,008 36.21 Vested (293,239 ) (198,762 ) 20.17 Forfeited (39,735 ) (59,743 ) 25.60 Equity awards outstanding at December 31, 2019 823,985 1,224,668 $ 24.20

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	The computation of basic and diluted earnings per share follows. Year Ended December 31, 2019 (in millions, except per share amounts) Income (Loss) Average Shares EPS Net income $ 113.3 Unvested restricted share participation (1.1 ) Net income per common share – basic 112.2 47.9 $ 2.34 Effect of dilutive securities: Nonparticipating unvested restricted shares — 0.5 Net income per common share – diluted $ 112.2 48.4 $ 2.32 Year Ended December 31, 2018 (in millions, except per share amounts) Income (Loss) Average Shares EPS Net income $ 75.7 Unvested restricted share participation (0.2 ) Net income per common share – basic 75.5 48.8 $ 1.55 Effect of dilutive securities: Nonparticipating unvested restricted shares — 0.1 Net income per common share – diluted $ 75.5 48.9 $ 1.54 Year Ended December 31, 2017 (in millions, except per share amounts) Income (Loss) Average Shares EPS Net income $ 89.7 Unvested restricted share participation — Net income per common share – basic 89.7 48.8 $ 1.84 Effect of dilutive securities: Nonparticipating unvested restricted shares — — Net income per common share – diluted $ 89.7 48.8 $ 1.84

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Data (unaudited)	Three Months Ended March 31, 2019 June 30, 2019 September 30, 2019 December 31, 2019 (in millions except per share data) Revenues $ 410.9 $ 434.1 $ 445.0 $ 446.9 Operating costs: Cost of revenues 332.8 345.7 356.7 369.3 Selling, general, and administrative expenses 40.8 46.1 45.5 47.1 Operating profit 37.3 42.3 42.8 30.5 Income before income taxes 35.6 40.8 41.9 28.5 Provision for income taxes 7.9 9.0 9.2 7.4 Net income $ 27.7 $ 31.8 $ 32.7 $ 21.1 Net income per common share: Basic $ 0.57 $ 0.66 $ 0.68 $ 0.44 Diluted $ 0.56 $ 0.65 $ 0.67 $ 0.43 Three Months Ended March 31, 2018 June 30, 2018 September 30, 2018 December 31, 2018 (in millions except per share data) Revenues $ 354.4 $ 353.0 $ 378.6 $ 374.4 Operating costs: Cost of revenues 285.6 283.0 308.9 310.9 Selling, general, and administrative expenses 37.6 39.4 40.1 36.8 Impairment charge — — 23.2 — Operating profit 31.2 30.6 6.4 26.7 Income before income taxes 30.2 29.4 6.6 28.8 Provision for income taxes 8.0 6.8 3.4 1.1 Net income $ 22.2 $ 22.6 $ 3.2 $ 27.7 Net income per common share (1) : Basic $ 0.45 $ 0.46 $ 0.07 $ 0.56 Diluted $ 0.45 $ 0.46 $ 0.07 $ 0.56 (1) For periods prior to the Separation, the denominator for basic and diluted net income per common share was calculated using the 48.8 million shares of common stock outstanding immediately following the Separation.

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Relationship with Former Parent and Related Entities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Trinity Industries, Inc. [Member]
Sales to Trinity businesses	$ 160.3	$ 148.3
Purchases from Trinity businesses	44.5	53.2
Corporate Segment
Corporate overhead costs	$ 26	$ 39.3

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Stockholder's Equity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Nov. 01, 2018
Accounting Policies [Abstract]
Authorized amount from Board of Directors for share repurchase		$ 50,000,000
Number of shares repurchased	361,442
Cost of shares repurchased	$ 11,000,000	$ 3,000,000
Remaining authorized repurchase amount	$ 36,000,000
Common stock, shares authorized	200,000,000	200,000,000	200,000,000
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Contract with customer	$ 50.8	$ 44

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Unsatisfied Performance Obligations (Details) $ in Millions	Dec. 31, 2019USD ($)
Wind towers and utility structures | Energy Equipment Group
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Unsatisfied performance obligations, Amount	$ 596.8
Unsatisfied performance obligations, Percent expected to be delivered in 2020	86.00%
Other | Energy Equipment Group
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Unsatisfied performance obligations, Amount	$ 36.2
Unsatisfied performance obligations, Percent expected to be delivered in 2020	100.00%
Inland barge | Transportation Products Group
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Unsatisfied performance obligations, Amount	$ 346.9
Unsatisfied performance obligations, Percent expected to be delivered in 2020	100.00%

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Inventories (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Accounting Policies [Abstract]
Inventory write down	$ 6.1

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Property, Plant, and Equipment (Details)	12 Months Ended
	Dec. 31, 2019
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	30 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	11 years
Machinery and other | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	2 years
Machinery and other | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Technology equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	2 years
Technology equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Long-lived Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
Accounting Policies [Abstract]
Indefinite-lived intangible assets (excluding goodwill)	$ 34,100,000		$ 34,100,000
Impairment of long-lived assets held-for-use	$ 0	$ 0

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment charges	$ 0	$ 0
Net book value of intangible assets	51.7	55.2
Indefinite-lived intangible assets (excluding goodwill)	34.1	34.1
Intangible assets, gross	44.6	44.6
Amortization expense from intangible assets	$ 3.4	$ 4.7	$ 5
Minimum
Finite-Lived Intangible Assets [Line Items]
Intangible assets with defined useful lives, amortization period	1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Intangible assets with defined useful lives, amortization period	12 years

Summary of Significant Accou_12

Summary of Significant Accounting Policies - Warranties (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Product Warranty Liability [Line Items]
Warranty accrual	$ 2.6	$ 2.9
Minimum
Product Warranty Liability [Line Items]
Product warranty period against materials and manufacturing defects	1 year
Maximum
Product Warranty Liability [Line Items]
Product warranty period against materials and manufacturing defects	5 years

Summary of Significant Accou_13

Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contractual lease liability	$ 19
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reduction in retained earnings due to adoption of ASU 2014-09			$ 4
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use asset		$ 23.7
Contractual lease liability		$ 27.5

Acquisitions and Divestitures -

Acquisitions and Divestitures - Acquisition and divestiture activites (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Acquisitions:
Purchase price	$ 39.2	$ 334.1	$ 63
Net cash paid	32.9	333.2	47.5
Goodwill recorded	$ 12.6	$ 120.9	$ 25

Acquisitions and Divestitures_2

Acquisitions and Divestitures - ACG preliminary purchase price allocation (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill	$ 621.9	$ 615.2
Construction Products Group
Business Acquisition [Line Items]
Goodwill	166.2	$ 171.7
Construction Products Group | ACG Materials
Business Acquisition [Line Items]
Accounts receivable	23.8
Inventories	12.5
Property, plant, and equipment	77.8
Mineral reserves	137.3
Goodwill	105.5
Other assets	6.3
Accounts payable	(10.2)
Accrued and other liabilities	(14.5)
Capital lease obligations	(8.3)
Deferred income taxes	(21.1)
Total net assets acquired	$ 309.1

Acquisitions and Divestitures_3

Acquisitions and Divestitures - ACG unaudited pro-forma information (Details) - ACG Materials - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Revenues	$ 1,604.1	$ 1,594.4
Income before income taxes	$ 97.6	$ 133.6

Acquisitions and Divestitures_4

Acquisitions and Divestitures - Narrative (Details) $ in Millions

Jan. 06, 2020USD ($)

Dec. 31, 2018USD ($)

Mar. 31, 2018USD ($)

Jul. 31, 2017USD ($)

May 31, 2017USD ($)

Dec. 31, 2018USD ($)

Sep. 30, 2018USD ($)

Jun. 30, 2018USD ($)

Mar. 31, 2018USD ($)

Dec. 31, 2019USD ($)businesses_divested

Dec. 31, 2018USD ($)businesses_divested

Dec. 31, 2017USD ($)businesses_divested

Business Acquisition [Line Items]

Purchase price

$ 39.2

$ 334.1

$ 63

Net cash paid

32.9

333.2

47.5

Goodwill recorded

12.6

120.9

25

Stock issued for acquisition (value)

14.7

Impairment charge

$ 0

$ 23.2

$ 0

$ 0

$ 0

23.2

$ 0

Number of divestitures | businesses_divested

0

0

Number of businesses acquired | businesses_divested

0

0

ACG Materials

Business Acquisition [Line Items]

Revenues from acquiree included in Statement of Operations

$ 11.7

Construction Products Group | ACG Materials

Business Acquisition [Line Items]

Purchase price

$ 309.1

Construction Products Group | Lightweight aggregates business

Business Acquisition [Line Items]

Purchase price

$ 6.2

Construction Products Group | Trench shoring products business

Business Acquisition [Line Items]

Purchase price

$ 42.1

Transportation Products Group | Inland barge components business

Business Acquisition [Line Items]

Goodwill recorded

$ 12.2

Transportation Products Group | Inland barge business

Business Acquisition [Line Items]

Purchase price

$ 25

Goodwill recorded

$ 9.5

Transportation Products Group and Construction Products Group | Inland barge components and construction aggregates business

Business Acquisition [Line Items]

Purchase price

39.2

Transportation Products Group and Construction Products Group | Construction aggregates business

Business Acquisition [Line Items]

Goodwill recorded

$ 0.4

Energy Equipment Group

Business Acquisition [Line Items]

Number of divestitures | businesses_divested

2

Number of businesses acquired | businesses_divested

0

Revolving credit facility | ACG Materials

Business Acquisition [Line Items]

Borrowing to fund acquisition purchase price

$ 180

Subsequent event | Construction Products Group | Cherry Industries, Inc.

Business Acquisition [Line Items]

Purchase price

$ 298

Subsequent event | Revolving credit facility | Cherry Industries, Inc.

Business Acquisition [Line Items]

Borrowing to fund acquisition purchase price

$ 150

Fair Value Accounting - Assets

Fair Value Accounting - Assets and liabilities measured at fair value on recurring basis (Details) - Fair value measurements, recurring - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Assets:
Cash equivalents		$ 155.3	$ 30
Total assets		155.3	30
Liabilities:
Contingent consideration liability	[1]	6.4
Total liabilities		10.7	1.2
Interest rate hedges
Liabilities:
Derivative liability	[2]	4.3	1.2
Level 1
Assets:
Cash equivalents		155.3	30
Total assets		155.3	30
Liabilities:
Contingent consideration liability	[1]	0
Total liabilities		0	0
Level 1 | Interest rate hedges
Liabilities:
Derivative liability	[2]	0	0
Level 2
Assets:
Cash equivalents		0	0
Total assets		0	0
Liabilities:
Contingent consideration liability	[1]	0
Total liabilities		4.3	1.2
Level 2 | Interest rate hedges
Liabilities:
Derivative liability	[2]	4.3	1.2
Level 3
Assets:
Cash equivalents		0	0
Total assets		0	0
Liabilities:
Contingent consideration liability	[1]	6.4
Total liabilities		6.4	0
Level 3 | Interest rate hedges
Liabilities:
Derivative liability	[2]	$ 0	$ 0
[1]	Current portion included in accrued liabilities and non-current portion included in other liabilities on the Consolidated Balance Sheets.
[2]	Included in other liabilities on the Consolidated Balance Sheet.

Segment Information - Financial

Segment Information - Financial information for segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 446.9	$ 445	$ 434.1	$ 410.9	$ 374.4	$ 378.6	$ 353	$ 354.4	$ 1,736.9	$ 1,460.4	$ 1,462.4
Operating Profit (Loss)	30.5	$ 42.8	$ 42.3	$ 37.3	26.7	$ 6.4	$ 30.6	$ 31.2	152.9	94.9	131.7
Assets	2,302.5				2,172.2				2,302.5	2,172.2	1,602.5
Depreciation, Depletion, & Amortization									85.8	67.6	65.7
Capital Expenditures									85.4	44.8	82.4
Total
Segment Reporting Information [Line Items]
Revenues									1,742	1,463.8	1,466.3
Operating Profit (Loss)									200.2	127.3	171
Assets	2,036.4				2,051				2,036.4	2,051	1,577.5
Depreciation, Depletion, & Amortization									82.2	67.1	65.7
Capital Expenditures									77	43.5	82.4
Corporate
Segment Reporting Information [Line Items]
Revenues									0	0	0
Operating Profit (Loss)									(47.3)	(32.1)	(39.3)
Assets	266.1				121.2				266.1	121.2	25
Depreciation, Depletion, & Amortization									3.6	0.5	0
Capital Expenditures									8.4	1.3	0
Construction Products Group
Segment Reporting Information [Line Items]
Assets	785				769.8				785	769.8	391.2
Depreciation, Depletion, & Amortization									38	21.9	18.4
Capital Expenditures									30.2	17.2	48.9
Construction Products Group | Total
Segment Reporting Information [Line Items]
Revenues									439.7	292.3	258.9
Operating Profit (Loss)									52.7	50.4	53.7
Energy Equipment Group
Segment Reporting Information [Line Items]
Assets	934.9				976.2				934.9	976.2	928.8
Depreciation, Depletion, & Amortization									27.9	29.7	30.2
Capital Expenditures									25	16	27.7
Energy Equipment Group | Total
Segment Reporting Information [Line Items]
Revenues									836.6	780.1	844.1
Operating Profit (Loss)									100.7	28.6	78.4
Transportation Products Group
Segment Reporting Information [Line Items]
Assets	316.5				305				316.5	305	257.5
Depreciation, Depletion, & Amortization									16.3	15.5	17.1
Capital Expenditures									21.8	10.3	5.8
Transportation Products Group | Total
Segment Reporting Information [Line Items]
Revenues									465.7	391.4	363.3
Operating Profit (Loss)									46.8	48.4	39
Other
Segment Reporting Information [Line Items]
Assets					0					0	0
Depreciation, Depletion, & Amortization										0	0
Capital Expenditures										0	0
Other | Total
Segment Reporting Information [Line Items]
Revenues										0	0
Operating Profit (Loss)										(0.1)	(0.1)
Construction aggregates | Construction Products Group
Segment Reporting Information [Line Items]
Revenues									364.7	217.9	204.9
Other | Construction Products Group
Segment Reporting Information [Line Items]
Revenues									75	74.4	54
Other | Energy Equipment Group
Segment Reporting Information [Line Items]
Revenues									211.2	197.2	192
Wind towers and utility structures | Energy Equipment Group
Segment Reporting Information [Line Items]
Revenues									625.4	582.9	652.1
Inland barge | Transportation Products Group
Segment Reporting Information [Line Items]
Revenues									293.9	170.2	157.9
Steel components | Transportation Products Group
Segment Reporting Information [Line Items]
Revenues									171.8	221.2	205.4
Eliminations
Segment Reporting Information [Line Items]
Assets	$ 0				$ 0				0	0	0
Depreciation, Depletion, & Amortization									0	0	0
Capital Expenditures									0	0	0
Eliminations | Intersegment
Segment Reporting Information [Line Items]
Revenues									(5.1)	(3.4)	(3.9)
Operating Profit (Loss)									$ 0	$ (0.3)	$ 0

Segment Information - Revenues,

Segment Information - Revenues, operating profit, total assets, and long-lived assets for Mexico operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 446.9	$ 445	$ 434.1	$ 410.9	$ 374.4	$ 378.6	$ 353	$ 354.4	$ 1,736.9	$ 1,460.4	$ 1,462.4
Operating profit	30.5	$ 42.8	$ 42.3	$ 37.3	26.7	$ 6.4	$ 30.6	$ 31.2	152.9	94.9	131.7
Total Assets	2,302.5				2,172.2				2,302.5	2,172.2	1,602.5
Mexico:
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									198.1	190.5	180.8
Operating profit									4.8	(11)	1.4
Total Assets	202.2				203.8				202.2	203.8
Long-Lived Assets	$ 85.5				$ 85.8				85.5	85.8
Mexico: | External
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									110.1	108.2	118.2
Mexico: | Intercompany
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 88	$ 82.3	$ 62.6

Segment Information - Narrative

Segment Information - Narrative (Details) - segment	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Product Information [Line Items]
Number of reportable segments	3
Revenue | Energy Equipment Group | Customer Concentration Risk
Product Information [Line Items]
Revenue concentration risk, percentage	18.20%	19.40%	22.90%

Property, Plant, and Equipmen_2

Property, Plant, and Equipment - Components of property, plant, and equipment (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost		$ 1,406.2	$ 1,328.7
Less: accumulated depreciation and depletion		(590)	(525.7)
Property, plant, and equipment, net		816.2	803
Productive Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost		211	201.9
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	[1]	331.4	316.5
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost		280.5	267.5
Machinery and other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost		755.7	715.9
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost		$ 38.6	$ 28.8
[1]	Includes depletable land of $211.0 million as of December 31, 2019 and $201.9 million as of December 31, 2018

Property, Plant, and Equipmen_3

Property, Plant, and Equipment - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, net	$ 816.2	$ 803
Manufacturing Facility, Nonoperating
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, net	$ 47.4

Goodwill - Goodwill (Details)

Goodwill - Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill	$ 621.9	$ 615.2
Goodwill impairment charges	0	0
Construction Products Group
Goodwill [Line Items]
Goodwill	166.2	171.7
Energy Equipment Group
Goodwill [Line Items]
Goodwill	416.9	416.9
Transportation Products Group
Goodwill [Line Items]
Goodwill	$ 38.8	$ 26.6

Debt - Components of debt (Deta

Debt - Components of debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Finance leases	$ 7.3	$ 5.5
Total debt	107.3	185.5
Line of credit | Revolving credit facility
Debt Instrument [Line Items]
Revolving credit facility	$ 100	$ 180

Debt - Remaining principal paym

Debt - Remaining principal payments under existing debt agreements (Details) - Line of credit - Revolving credit facility $ in Millions	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
2020	$ 0
2021	0
2022	0
2023	100
2024	0
Thereafter	$ 0

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($) $ in Millions	Jan. 02, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 01, 2018
Debt Instrument [Line Items]
Letters of credit outstanding expiring in current fiscal year		$ 42.5
Revolving credit facility | Line of credit
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity				$ 400
Line of credit commitment fee percentage		0.20%
Revolving credit facility		$ 100	$ 180
Credit facility, remaining borrowing capacity		257.5
Unamortized debt issuance costs		1.2
Letter of credit | Line of credit
Debt Instrument [Line Items]
Letters of credit outstanding		42.5
Interest rate hedges | Designated as hedging instrument
Debt Instrument [Line Items]
Derivative, notional amount			$ 100
Derivative fixed interest rate			2.71%
Derivative liability		$ 4.3
LIBOR | Revolving credit facility | Line of credit
Debt Instrument [Line Items]
Credit facility, margin on LIBOR interest rate		1.25%
Subsequent event | Revolving credit facility | Line of credit
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 500
Subsequent event | Revolving credit facility | Long-term debt
Debt Instrument [Line Items]
Line of credit commitment fee percentage	0.25%
Term-loan facility	$ 150
Subsequent event | LIBOR | Revolving credit facility | Long-term debt
Debt Instrument [Line Items]
Credit facility, margin on LIBOR interest rate	1.50%
Minimum | Revolving credit facility | Line of credit
Debt Instrument [Line Items]
Credit facility, margin on LIBOR interest rate		1.25%
Line of credit commitment fee percentage		0.20%
Maximum | Revolving credit facility | Line of credit
Debt Instrument [Line Items]
Credit facility, margin on LIBOR interest rate		2.00%
Line of credit commitment fee percentage		0.35%

Leases Operating leases (Detail

Leases Operating leases (Details) $ in Millions	Dec. 31, 2019USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	$ 6.4
2021	4
2022	2.6
2023	2
2024	1.7
Thereafter	6
Total undiscounted operating lease payments	22.7
Less imputed interest	3.7
Present value of operating lease liabilities	$ 19
Weighted average remaining lease term	5 years 9 months 18 days
Weighted average discount rate	4.80%
Other assets
Right of use asset	$ 15.6
Accrued liabilities
Operating lease, current liability	5.5
Other liabilities
Operating Lease, noncurrent liability	$ 13.5

Leases Prior to adoption of ASU

Leases Prior to adoption of ASU 2016-02 (Details) - Prior to adoption of ASU 2016-02 [Domain] $ in Millions	Dec. 31, 2018USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
2019	$ 7.7
2020	5.7
2021	3.5
2022	2.3
2023	1.8
Thereafter	7.6
Total undiscounted operating lease payments	$ 28.6

Leases (Details)

Leases (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 8.2
Operating lease payments	$ 7.8

Other, Net - Summary of other,

Other, Net - Summary of other, net (income) expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Income and Expenses [Abstract]
Interest income	$ (1.4)	$ (0.4)	$ (0.1)
Foreign currency exchange transactions	1.5	(0.2)	2.2
Other	(0.8)	(0.4)	(0.5)
Other, net (income) expense	$ (0.7)	$ (1)	$ 1.6

Income Taxes - Components of th

Income Taxes - Components of the provision for income taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal									$ 7.6	$ (5.4)	$ 29.3
State									3	0.8	0.5
Foreign									5.6	1.5	0.3
Total current									16.2	(3.1)	30.1
Deferred:
Effect of tax cuts and jobs act - Deferred federal									0	(1.5)	(6.2)
Other - Deferred federal									22.6	24.8	16.6
Federal									22.6	23.3	10.4
State									(0.6)	5.4	0.9
Foreign									(4.7)	(6.3)	(1)
Total deferred									17.3	22.4	10.3
Provision (benefit) for income taxes	$ 7.4	$ 9.2	$ 9	$ 7.9	$ 1.1	$ 3.4	$ 6.8	$ 8	$ 33.5	$ 19.3	$ 40.4

Income Taxes - Reconciliation b

Income Taxes - Reconciliation between the statutory U.S. Federal income tax rate and the Company's effective income tax rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	21.00%	35.00%
State taxes	3.10%	3.10%	2.50%
Domestic production activities deduction	0.00%	0.00%	(2.10%)
Changes in valuation allowances and reserves	(1.30%)	(1.20%)	1.30%
Changes in tax reserves	(0.30%)	(1.40%)	0.80%
Effect of Tax Cuts and Jobs Act	0.00%	(1.60%)	(5.00%)
Prior year true ups	(0.50%)	(0.40%)	(2.20%)
Foreign adjustments	0.60%	2.40%	1.80%
Other, net	0.20%	(1.60%)	(1.00%)
Effective rate	22.80%	20.30%	31.10%

Income Taxes - Components of de

Income Taxes - Components of deferred tax liabilities and assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax liabilities:
Depreciation, depletion, and amortization	$ 109.1	$ 103.2
Total deferred tax liabilities	109.1	103.2
Deferred tax assets:
Workers compensation, pensions, and other benefits	21.6	16.2
Warranties and reserves	1.7	2.2
Tax loss carryforwards and credits	14.8	31
Inventory	22.7	10.8
Accrued liabilities and other	1	(2.7)
Total deferred tax assets	61.8	57.5
Net deferred tax assets (liabilities) before valuation allowances	(47.3)	(45.7)
Valuation allowances	4.8	5.7
Adjusted net deferred tax assets (liabilities)	$ 52.1	$ 51.4

Income Taxes - Change in unreco

Income Taxes - Change in unrecognized tax benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 0.5	$ 1.3	$ 7.4
Additions for tax positions related to the current year	0	0	0
Additions for tax positions of prior years	0	0.1	0.2
Reductions for tax positions of prior years	0	0	0
Settlements	0	0	(6)
Expiration of statute of limitations	(0.5)	(0.9)	(0.3)
Ending balance	$ 0	$ 0.5	$ 1.3

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Statutory rate	21.00%	21.00%	35.00%
Effect of tax cuts and jobs act - Deferred federal	$ 0	$ 1.5	$ 6.2
Income before income taxes for U.S. operations	143.6	106.6	139.9
Income before income taxes for foreign operations	3.2	(11.6)	(9.8)
Net operating loss carryforwards - domestic	22
Remaining state loss carryforwards	0.6
Net operating loss carryforwards - foreign	36.9
Additions for tax positions of prior years	0	0.1	0.2
Unrecognized tax benefits including interest and penalties that would affect the Company's effective tax rate if recognized		0.5	1.9
Unrecognized tax benefits, reduction resulting from statute of limitations	0.5	0.9	0.3
Total accrued interest and penalties related to uncertain tax positions	0	0	0.9
Increase (decrease) in income tax expense related to interest and penalties on unrecognized tax benefits	0	$ 0.9	$ 1.5
Undistributed earnings of foreign subsidiaries	$ 79.4

Employee Retirement Plans - Tot

Employee Retirement Plans - Total employee retirement plan expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Defined contribution plans	$ 8.5	$ 8.3	$ 6.9
Multiemployer plan	1.8	2.1	2.1
Total retirement plan expense	$ 10.3	$ 10.4	$ 9

Employee Retirement Plans - Det

Employee Retirement Plans - Details of the multiemployer plan (Details) - Boilermaker-Blacksmith National Pension Trust - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Multiemployer Plans [Line Items]
PPA Zone Status	Red	Yellow
Financial improvement plan status	Implemented
Multiemployer plan contributions	$ 1.8	$ 2.1	$ 1.9
Surcharge imposed	Yes
Expiration date of collective bargaining agreement	Jun. 30, 2022

Employee Retirement Plans - Nar

Employee Retirement Plans - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Schedule of Benefit Plans Disclosures [Line Items]
Plan assets	$ 3.2
Projected benefit obligation	3.1
Multiemployer plan, expected contributions in following year	$ 1.8
Maximum
Schedule of Benefit Plans Disclosures [Line Items]
Company's contributions to multiemployer plan as a percentage of total contributions (less than)	5.00%
Other assets
Schedule of Benefit Plans Disclosures [Line Items]
Deferred compensation plan assets	$ 3.9
Funded status of plan	0.1
Other liabilities
Schedule of Benefit Plans Disclosures [Line Items]
Deferred compensation liability	$ 2.8

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Changes in accumulated other comprehensive loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments for losses included in net income, net of tax expense (benefit)	$ 0	$ (3)	$ 0
AOCI Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(17.7)	(19.8)	(18.4)
Other comprehensive income (loss), net of tax, before reclassifications	(2.3)	(0.9)	(1.4)
Reclassification adjustments for losses included in net income, net of tax expense (benefit)	(0.3)	(3)
Other comprehensive income (loss)	(2)	2.1	(1.4)
Ending balance	(19.7)	(17.7)	(19.8)
Currency translation adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(16.8)	(19.8)	(18.4)
Other comprehensive income (loss), net of tax, before reclassifications	0.5	0	(1.4)
Reclassification adjustments for losses included in net income, net of tax expense (benefit)	0	(3)
Other comprehensive income (loss)	0.5	3	(1.4)
Ending balance	(16.3)	(16.8)	(19.8)
Unrealized loss on derivative financial instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(0.9)	0	0
Other comprehensive income (loss), net of tax, before reclassifications	(2.8)	(0.9)	0
Reclassification adjustments for losses included in net income, net of tax expense (benefit)	0.3	0
Other comprehensive income (loss)	(2.5)	(0.9)	0
Ending balance	$ (3.4)	$ (0.9)	$ 0

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss Amounts reclassified from accumulated other comprehensive income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, Current Period, Tax	$ 0	$ 0	$ 0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, Current Period, Tax	0.1	0	0
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, Current Period, Tax	$ 0.1	$ 0	$ 0

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of restricted stock activity (Details) - Restricted share awards	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted Average Grant-Date Fair Value per Award, Equity awards outstanding, Beginning balance (in dollars per share) | $ / shares	$ 21.12
Weighted Average Grant-Date Fair Value per Award, Granted (in dollars per share) | $ / shares	36.21
Weighted Average Grant-Date Fair Value per Award, Vested (in dollars per share) | $ / shares	20.17
Weighted Average Grant-Date Fair Value per Award, Forfeited (in dollars per share) | $ / shares	25.60
Weighted Average Grant-Date Fair Value per Award, Equity awards outstanding, Ending balance (in dollars per share) | $ / shares	$ 24.20
Trinity Equity Awards Held by Arcosa Employees
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Equity Awards, Restricted share awards outstanding, Beginning balance (in shares)	1,156,959
Number of Equity Awards, Granted (in shares)	0
Number of Equity Awards, Vested (in shares)	(293,239)
Number of Equity Awards, Forfeited (in shares)	(39,735)
Number of Equity Share Awards, Restricted share awards outstanding, Ending balance (in shares)	823,985
Arcosa Equity Awards Held by Arcosa Employees
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Equity Awards, Restricted share awards outstanding, Beginning balance (in shares)	1,066,165
Number of Equity Awards, Granted (in shares)	417,008
Number of Equity Awards, Vested (in shares)	(198,762)
Number of Equity Awards, Forfeited (in shares)	(59,743)
Number of Equity Share Awards, Restricted share awards outstanding, Ending balance (in shares)	1,224,668

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock provided for awarding by the Plan (in shares)	4,800,000
Number of shares available for issuance (in shares)	2,400,000
Stock-based compensation expense	$ 14.6	$ 9.9	$ 9
Income tax benefit related to stock-based compensation expense	2.7	$ 2.6	$ 4.6
Fair value of shares vested	$ 13.3
Restricted Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Restricted Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	15 years
Restricted share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to restricted share awards	$ 24.6
Weighted average recognition period	2 years 10 months 24 days
Performance units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target grant potentially issuable depending on achievement of certain specified goals	0.00%
Performance units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target grant potentially issuable depending on achievement of certain specified goals	200.00%

Earnings Per Common Share - Com

Earnings Per Common Share - Computation of basic and diluted earnings per share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended														12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018	Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share Reconciliation [Abstract]
Net income		$ 21.1	$ 32.7		$ 31.8		$ 27.7		$ 27.7	$ 3.2		$ 22.6		$ 22.2		$ 113.3	$ 75.7	$ 89.7
Unvested restricted share participation																(1.1)	(0.2)	0
Net income per common share – basic																$ 112.2	$ 75.5	$ 89.7
Net income - basic (shares)	[1]															47.9	48.8	48.8
Net income - basic (EPS)		$ 0.44	$ 0.68	[1]	$ 0.66	[1]	$ 0.57	[1]	$ 0.56	$ 0.07	[1]	$ 0.46	[1]	$ 0.45	[1]	$ 2.34	$ 1.55	$ 1.84
Effect of dilutive securities:
Nonparticipating unvested restricted shares																$ 0	$ 0	$ 0
Nonparticipating unvested restricted shares (shares)																0.5	0.1	0
Net income per common share – diluted																$ 112.2	$ 75.5	$ 89.7
Net income - diluted (shares)	[1]															48.4	48.9	48.8
Net income - diluted (EPS)		$ 0.43	$ 0.67	[1]	$ 0.65	[1]	$ 0.56	[1]	$ 0.56	$ 0.07	[1]	$ 0.46	[1]	$ 0.45	[1]	$ 2.32	$ 1.54	$ 1.84
[1]	For periods prior to the Separation, the denominator for basic and diluted net income per common share was calculated using the 48.8 million shares of common stock outstanding immediately following the Separation.

Earnings Per Common Share - Nar

Earnings Per Common Share - Narrative (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2018
Earnings Per Share [Abstract]
Common stock immediately after spin off				48.8
Weighted average restricted shares	1.6	0.3	0

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Millions	Dec. 31, 2019USD ($)
Loss Contingencies [Line Items]
Non-cancelable purchase obligations	$ 168.9
Accrued liabilities
Loss Contingencies [Line Items]
Total accrual	3.6
Environmental matters
Loss Contingencies [Line Items]
Total accrual	1.4
Minimum
Loss Contingencies [Line Items]
Range of reasonably possible losses	1.1
Maximum
Loss Contingencies [Line Items]
Range of reasonably possible losses	4.6
Energy Equipment and Transportation Products Group | Inventories
Loss Contingencies [Line Items]
Non-cancelable purchase obligations	$ 110.1

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) - Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended														12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018	Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 446.9	$ 445		$ 434.1		$ 410.9		$ 374.4	$ 378.6		$ 353		$ 354.4		$ 1,736.9	$ 1,460.4	$ 1,462.4
Operating costs:
Cost of revenues	369.3	356.7		345.7		332.8		310.9	308.9		283		285.6		1,404.5	1,188.4	1,167.7
Selling, general, and administrative expenses	47.1	45.5		46.1		40.8		36.8	40.1		39.4		37.6		179.5	153.9	163
Impairment charge								0	23.2		0		0		0	23.2	0
Operating profit	30.5	42.8		42.3		37.3		26.7	6.4		30.6		31.2		152.9	94.9	131.7
Income before income taxes	28.5	41.9		40.8		35.6		28.8	6.6		29.4		30.2		146.8	95	130.1
Provision (benefit) for income taxes	7.4	9.2		9		7.9		1.1	3.4		6.8		8		33.5	19.3	40.4
Net income	$ 21.1	$ 32.7		$ 31.8		$ 27.7		$ 27.7	$ 3.2		$ 22.6		$ 22.2		$ 113.3	$ 75.7	$ 89.7
Net income per common share:
Basic (in dollars per share)	$ 0.44	$ 0.68	[1]	$ 0.66	[1]	$ 0.57	[1]	$ 0.56	$ 0.07	[1]	$ 0.46	[1]	$ 0.45	[1]	$ 2.34	$ 1.55	$ 1.84
Diluted (in dollars per share)	$ 0.43	$ 0.67	[1]	$ 0.65	[1]	$ 0.56	[1]	$ 0.56	$ 0.07	[1]	$ 0.46	[1]	$ 0.45	[1]	$ 2.32	$ 1.54	$ 1.84
[1]	For periods prior to the Separation, the denominator for basic and diluted net income per common share was calculated using the 48.8 million shares of common stock outstanding immediately following the Separation.