Summary of Business and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation - The accompanying consolidated financial statements include the accounts of subsidiaries and construction joint ventures in which the Company has 50% or greater than ownership interest or otherwise exercises control over such entities. For investments in construction joint ventures that are not wholly-owned, but where the Company exercises control, the equity held by the remaining owners and their portions of net income (loss) are reflected in the balance sheet line item “Noncontrolling interests” in “Equity” and the statement of operations line item “Noncontrolling interests in earnings,” respectively. For investments in subsidiaries that are not wholly-owned, but where the Company exercises control and where the Company has a mandatorily redeemable interest, the equity held by the remaining owners and their portion of net income (loss) is reflected in the balance sheet line item “Members' interest subject to mandatory redemption and undistributed earnings” and the statement of operations line item “Other operating expense, net” respectively. All significant intercompany accounts and transactions have been eliminated in consolidation. Refer to Note 5 for further information regarding the Company’s Consolidated 50% Owned Subsidiaries, including Variable Interest Entities. Where the Company is a noncontrolling joint venture partner, and is otherwise not required to consolidate the joint venture entity, its share of the earnings of such construction joint venture is accounted for on a pro rata basis in the consolidated statements of operations and as a single line item (“Receivables from and equity in construction joint ventures”) in the consolidated balance sheets. This method is a permissible modification of the equity method of accounting which is a common practice in the construction industry. Refer to Note 6 for further information regarding the Company’s Construction Joint Ventures. Under accounting principles generally accepted in the United States (“GAAP”), the Company must determine whether each entity, including joint ventures in which it participates, is a variable interest entity (“VIE”). This determination focuses on identifying which owner or joint venture partner, if any, has the power to direct the activities of the entity and the obligation to absorb losses of the entity or the right to receive benefits from the entity disproportionate to its interest in the entity, which could have the effect of requiring the Company to consolidate the entity in which it has a noncontrolling variable interest. Refer to Note 5 for further information regarding the Company’s Consolidated 50% Owned Subsidiaries, including VIEs.
Use of Estimates	Use of Estimates - The preparation of the accompanying
Reclassification	Reclassification - Reclassifications have been made to historical financial data in our consolidated financial statements to conform to our current year presentation.
Revenue Recognition	Revenue Recognition Heavy Civil Construction - The Company engages in various types of heavy civil construction projects principally for public (government) owners. Revenues are recognized as performance obligations are satisfied over time (formerly known as percentage-of-completion method), using the ratio of costs incurred to estimated total costs for each contract. This cost to cost measure is used because management considers it to be the best available measure of progress on these contracts. Contract costs include all direct material, labor, subcontract and other costs and those indirect costs determined to relate to contract performance, such as indirect salaries and wages, equipment repairs and depreciation, insurance and payroll taxes. Administrative and general expenses are charged to expense as incurred. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Changes in job performance, job conditions, estimated profitability and associated change orders and claims, including those changes arising from contract penalty provisions and final contract settlements, may result in revisions to costs and income and are recognized in the period in which the revisions are determined. Our contracts generally take 12 to 36 months to complete. The Company generally provides a one- to two-year warranty for workmanship under its contracts when completed. Warranty claims historically have been insignificant. Change orders are modifications of an original contract that effectively change the existing provisions of the contract without adding new provisions or terms. Change orders may include changes in specifications or designs, manner of performance, facilities, equipment, materials, sites and period of completion of the work. Either we or our customers may initiate change orders. The Company considers unapproved change orders to be contract variations for which we have customer approval for a change of scope but a price change associated with the scope change has not yet been agreed upon. Costs associated with unapproved change orders are included in the estimated costs to complete the contracts and are treated as project costs as incurred. The Company recognizes revenue equal to costs incurred on unapproved change orders when management determines approval to be probable. Unapproved change orders involve the use of estimates, and it is reasonably possible that revisions to the estimated costs and recoverable amounts may be required in future reporting periods to reflect changes in estimates or final agreements with customers. Change orders that are unapproved as to both price and scope are evaluated as claims. The Company considers claims to be amounts in excess of approved contract prices that we seek to collect from our customers or others for customer-caused delays, errors in specifications and designs, contract terminations, change orders that are either in dispute or are unapproved as to both scope and price, or other causes of unanticipated additional contract costs. Claims are included in the calculation of revenue when realization is probable and amounts can be reliably determined to the extent costs are incurred. To support these requirements, the existence of the following items must be satisfied: (i) the contract or other evidence provides a legal basis for the claim; or a legal opinion has been obtained, stating that under the circumstances there is a reasonable basis to support the claim; (ii) additional costs are caused by circumstances that were unforeseen at the contract date and are not the result of deficiencies in the contractor’s performance; (iii) costs associated with the claim are identifiable or otherwise determinable and are reasonable in view of the work performed; and (iv) the evidence supporting the claim is objective and verifiable, not based on management’s feel for the situation or on unsupported representations. Revenue in excess of contract costs incurred on claims is recognized when an agreement is reached with customers as to the value of the claims, which in some instances may not occur until after completion of work under the contract. Costs associated with claims are included in the estimated costs to complete the contracts and are treated as project costs when incurred. The Company has projects where we are in the process of negotiating, or awaiting final approval of, unapproved change orders and claims with our customers. The Company is proceeding with its contractual rights to recoup additional costs incurred from its customers based on completing work associated with change orders, including change orders with pending change order pricing, or claims related to significant changes in scope which resulted in substantial delays and additional costs in completing the work. Unapproved change order and claim information has been provided to our customers and negotiations with the customers are ongoing. If additional progress with an acceptable resolution is not reached, legal action will be taken. Based upon our review of the provisions of our contracts, specific costs incurred and other related evidence supporting the unapproved change orders, claims and our entitled unpaid project price, together with the views of the Company’s outside claim consultants, Sterling concluded that it was appropriate to include in project price amounts of $9.3 million and $10.0 million at December 31, 2018 and 2017, respectively, in “Costs and estimated earnings in excess of billings on uncompleted contracts” on our consolidated balance sheets. We expect these matters will be resolved without a material adverse effect on our financial statements. However, unapproved change order and claim amounts are subject to negotiations which may cause actual results to differ materially from estimated and recorded amounts. The asset, “Costs and estimated earnings in excess of billings on uncompleted contracts” represents revenues recognized in excess of amounts billed on these contracts and will be billed at a later date, usually due to contract terms. In addition, revenue associated with unapproved change orders and claims is also included when realization is probable and amounts can be reliably determined. The liability, “Billings in excess of costs and estimated earnings on uncompleted contracts” represents billings in excess of revenues recognized on these contracts. Residential Construction - Residential construction revenue and related profit are recognized when construction on the concrete foundation unit is completed (i.e., at a point in time). The time from starting construction to finishing is typically less than one month.
Fair Value of Financial Assets and Liabilities	Fair Value of Financial Assets and Liabilities - The fair value of financial instruments is the amount at which the instrument could be exchanged in a current transaction between willing parties. The Company’s financial instruments are cash and cash equivalents, restricted cash used as collateral for a letter of credit, restricted cash maintained in an escrow account, contracts receivable, accounts payable, notes payable, and term loan and associated warrants within the Oaktree Facility. The recorded values of cash and cash equivalents, restricted cash, contracts receivable and accounts payable approximate their fair values based on their liquidity and/or short-term nature. The Company provides credit in the normal course of business, principally to public (government) owners, and performs ongoing credit evaluations, as deemed necessary, but generally does not require collateral to support such receivables. The Company’s debt is recorded at its carrying amount, which approximates the fair values, in the consolidated balance sheets. Refer to Note 9 for further information regarding the Company's debt. Refer to Note 14 for further information regarding the warrants associated with the Oaktree Facility. The Company does not have any off-balance sheet financial instruments other than operating leases.
Receivables, including Retainage	Receivables, including Retainage - Receivables are generally based on amounts billed to the customer in accordance with the provisions of the agreement. At December 31, 2018 and 2017, receivables included $47.4 million and $43.5 million of retainage, respectively, discussed below, which is being withheld by customers until completion of the contracts. At December 31, 2018 and 2017, there were no unbilled receivables on contracts completed. Many of the contracts under which the Company performs work contain retainage provisions. Retainage refers to that portion of billings made by the Company but held for payment by the customer pending satisfactory completion of the project. Unless reserved, the Company assumes that all amounts retained by customers under such provisions are fully collectible. Retainage on active contracts is classified as a current asset regardless of the term of the contract and is generally collected within one year of the completion of a contract. We anticipate to collect approximately 75% of the retainage in 2019. Receivables are written off based on individual credit evaluation and specific circumstances of the customer, when such treatment is warranted. The Company performs a review of outstanding receivables, historical collection information and existing economic conditions to determine if there are potential uncollectible receivables. At December 31, 2018 and 2017, our allowance for doubtful accounts against contracts receivable was minimal. As is customary, we have agreed to indemnify our bonding company for all losses incurred by it in connection with bonds that are issued, and we have granted our bonding company a security interest in certain assets, including accounts receivable, as collateral for such obligation.
Inventories	Inventories - The Company’s inventories are stated at the lower of cost or market as determined by the average cost method. Inventories at December 31, 2018 and 2017 were $3.2 million and $4.6 million, respectively. Inventories consist primarily of residential slabs in process, concrete, aggregate, steel and millings which are primarily expected to be utilized on construction projects in the future. A small portion is sold to third parties. The cost of inventory can also include material, labor, trucking and other equipment costs.
Property and equipment	Property and equipment - Property and equipment are recorded at cost and depreciated on a straight-line basis over their estimated useful lives, including buildings and improvements (5 to 39 years) and plant and field equipment (5 to 15 years). Renewals and betterments that substantially extend the useful life of an asset are capitalized and depreciated. Leasehold improvements are depreciated over the lesser of the useful life of the asset or the applicable lease term.
Leases and Equipment under Capital Leases	Leases - We lease property and equipment in the ordinary course of our business. Our leases have varying terms. Some may include renewal options, escalation clauses, restrictions, penalties or other obligations that we consider in determining minimum lease payments. The leases are classified as either operating leases or capital leases, as appropriate. Through December 31, 2018, the Company recognized rent expense related to operating leases on a straight-line basis over the terms of the leases. Equipment under Capital Leases - The Company accounts for capital leases, which transfer substantially all the benefits and risks incident to the ownership of the leased property to the Company, as the acquisition of an asset and the incurrence of an obligation. Under this method of accounting, the recorded value of the leased asset is amortized principally using the straight-line method over its estimated useful life and the obligation, including interest thereon, is reduced through payments over the life of the lease. Depreciation expense on equipment subject to capital leases and the related accumulated depreciation is included with that of owned equipment. The Company had capital leases totaling $0.2 million and $0.3 million at December 31, 2018 and 2017, respectively. Capital leases are recorded in “Long-term debt, net of current maturities” and “Current maturities of long-term debt,” as applicable, in our consolidated balance sheets.
Deferred Loan Costs	Deferred Loan Costs - Deferred loan costs represent loan origination fees paid to the lender, related professional fees such as legal fees related to drafting of loan agreements and the fair valued warrants. See Note 9 for further information regarding the Company's debt.
Goodwill and Intangibles	Goodwill and Intangibles - Goodwill represents the excess of the cost of companies acquired over the fair value of their net assets at the dates of acquisition. GAAP requires that: (1) goodwill and indefinite lived intangible assets not be amortized, (2) goodwill is to be tested for impairment at least annually at the reporting unit level and (3) intangible assets deemed to have an indefinite life are to be tested for impairment at least annually by comparing the fair value of these assets with their recorded amounts. Refer to Note 8 for our disclosure regarding goodwill impairment testing.
Evaluating Impairment of Long-Lived Assets	Evaluating Impairment of Long-Lived Assets - When events or changes in circumstances indicate that long-lived assets may be impaired, an evaluation is performed. The evaluation would be based on estimated undiscounted cash flows associated with the assets as compared to the asset’s carrying amount to determine if a write-down to fair value is required. There was no impairment in 2018, 2017 and 2016. Management believes that there are no additional events or changes in circumstances which have indicated that other long-lived assets may be impaired.
Segment reporting	Segment reporting - Due to the April 3, 2017 acquisition of Tealstone, the Company has reviewed its reportable segments, operating segments and reporting units. Based on our review, we have concluded that our operations consist of two reportable segments and two reporting unit components: heavy civil construction and residential construction. In making this determination, the Company considered the discrete financial information used by our Chief Operating Decision Maker (“CODM”). Based on this approach, the Company noted that the CODM organizes, evaluates and manages the financial information of our aggregated heavy civil construction projects and the entire residential construction division separately when making operating decisions and assessing the Company’s overall performance. Furthermore, we considered the differences between the types of work performed in each reporting unit. Each heavy civil construction project has similar characteristics, includes similar services, has similar types of customers and is subject to similar economic and regulatory environments. Projects in our heavy civil construction segment typically last for several years, involve several subtasks and are accounted for using the over time recognition method (formerly known as percentage-of-completion method). Conversely, our residential construction projects typically consist of a high volume of independent units performed for customers that are billed, paid and accounted for as the individual units are completed. Each foundation unit completed in our residential construction segment typically takes less than one month from start to finish. Segment reporting is aligned based upon the services offered by our two operating groups, which represent our reportable segments: heavy civil construction and residential construction, as mentioned above. Our CODM evaluates the performance of the aforementioned operating groups based upon revenue and income from operations. Each operating group’s income from operations reflects corporate costs, allocated based primarily upon revenu
Federal and State Income Taxes	Federal and State Income Taxes - We determine deferred income tax assets and liabilities using the balance sheet method. Under this method, the net deferred tax asset or liability is determined based on the tax effects of the temporary differences between the book and tax bases of the various balance sheet assets and liabilities and gives current recognition to changes in tax rates and laws. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized. We recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the more-likely-than-not threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority. Refer to Note 12 for further information regarding our federal and state income taxes.
Share-Based Compensation	Stock-Based Compensation - The Company’s stock-based incentive plan is administered by the Company with oversight by the Compensation and Talent Development Committee of the Board of Directors. Awards under this plan give the recipients the right to receive shares of common stock once specified service or performance related vesting conditions are met. The Company recognizes expense based on the grant-date fair value of the service award and amortizes the award based on straight line methods. Awards based on performance vesting are subsequently remeasured at each reporting date through the settlement date. Awards that vest based on market criteria are valued using a valuation model that incorporates the probability of the Company meeting the stated criteria, such as the Monte-Carlo simulation, and the expense is amortized on a straight line basis over the term of the agreement. Upon the vesting of unvested common stock the Company may withhold shares, based on the employee’s election, in order to satisfy federal tax withholdings. The shares held by the Company are considered constructively retired and are retired shortly after withholding. The Company then remits the withholding taxes required. Refer to Note 14 for further information regarding the stock-based incentive plans.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-9, “Revenue from Contracts with Customers”. We adopted the requirements of the new standard effective January 1, 2018. See Note 3 for further information regarding the Company's revenue from contracts with customers. Recently Issued Accounting Pronouncements In February 2016, the FASB issued its new lease accounting guidance in ASU No. 2016-2, “Leases” (Topic 842). Under the new guidance, lessees will be required to recognize for all leases (with the exception of short-term leases) on the balance sheet a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis and a right-of-use asset (ROU), which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The new standard is effective for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. The company will adopt this standard during the first quarter of 2019 using the modified retrospective method, recognizing a cumulative-effect change to the opening balance of retained earnings in the period of adoption. The new guidance will be applied to leases that exist or are entered into on or after January 1, 2019 without adjusting comparative periods in the financial statements. The company expects to utilize the package of practical expedients that allows entities to 1) retain the classification of leases existing at the date of adoption; 2) not reassess initial costs for any existing leases; 3) not reassess whether any expired or existing contracts are or contain leases; and 4) short-term lease recognition exemption. Effective January 1, 2019, the Company expects to record an ROU asset and associated liability in the range of $14.0 million to $16.0 million on its consolidated balance sheet, related to its existing operating leases. The adoption of this standard is not expected to have a material impact on the Company’s consolidated statements of operations. The Company determines if an arrangement is a lease at inception. The operating lease ROU asset will be included within the Company’s other non-current assets, and lease liabilities will be included in current or noncurrent liabilities on the Company’s consolidated balance sheets. Operating lease ROU asset and operating lease liabilities will be recognized based on the present value of the future minimum lease payments over the lease term at commencement date. The operating lease ROU asset will also include any lease payments made and exclude lease incentives and initial direct costs incurred. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for minimum lease payments will continue to be recognized on a straight-line basis over the lease term. As of December 31, 2018, the remaining lease terms for the Company’s various operating leases extended out over the next 4 years. The discount rate used to determine the present value of the Company’s operating leases’ future payments was between 5.0% and 8.0%. For future leases, the implied rate in the lease will be used to determine the present value. In August 2016, the FASB issued guidance in ASU No. 2016-15 (Topic 230): “Classification of Certain Cash Receipts and Cash Payments.” This update addresses specific cash flow issues with the objective of reducing existing diversity in practice. Early adoption is permitted for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company expects to adopt this guidance as required and does not expect a material impact to the Company’s consolidated financial statements.