Sterling Infrastructure (STRL) 10-Q 5 May 20 2020 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 01, 2020
Document And Entity Information [Abstract]
Entity Registrant Name	STERLING CONSTRUCTION CO INC
Entity Central Index Key	0000874238
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		27,977,131
Document Type	10-Q
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Current Reporting Status	Yes
Amendment Flag	false
Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues	$ 296,688	$ 223,949
Cost of revenues	(261,443)	(204,446)
Gross profit	35,245	19,503
General and administrative expense	(17,604)	(11,889)
Intangible asset amortization	(2,837)	(600)
Acquisition related costs	(473)	0
Other operating expense, net	(2,228)	(2,294)
Operating income	12,103	4,720
Interest income	99	364
Interest expense	(7,803)	(3,060)
Income before income taxes	4,399	2,024
Income tax expense	(1,184)	(163)
Net income	3,215	1,861
Less: Net income attributable to noncontrolling interests	(100)	(46)
Net income attributable to Sterling common stockholders	$ 3,115	$ 1,815
Net income per share attributable to Sterling common stockholders:
Basic (in dollars per share)	$ 0.11	$ 0.07
Diluted (in dollars per share)	$ 0.11	$ 0.07
Weighted average common shares outstanding:
Basic (in shares)	27,736	26,377
Diluted (in shares)	27,992	26,723

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 3,215	$ 1,861
Loss on interest rate swap, net of tax	(7,061)	0
Total comprehensive (loss) income	(3,846)	1,861
Less: Comprehensive income attributable to noncontrolling interests	(100)	(46)
Comprehensive (loss) income attributable to Sterling common stockholders	$ (3,946)	$ 1,815

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Current assets:
Cash and cash equivalents ($7,126 and $7,538 related to variable interest entities (“VIEs”))	$ 73,905	$ 45,733
Accounts receivable, including retainage ($30,550 and $24,642 related to VIEs)	221,268	248,247
Costs and estimated earnings in excess of billings ($9,078 and $8,328 related to VIEs)	54,791	42,555
Receivables from and equity in construction joint ventures ($7,729 and $7,406 related to VIEs)	10,789	9,196
Other current assets ($1,047 and $503 related to VIEs)	10,335	11,790
Total current assets	371,088	357,521
Property and equipment, net ($5,627 and $5,619 related to VIEs)	117,818	116,030
Operating lease right-of-use assets ($3,938 and $3,817 related to VIEs)	14,790	13,979
Goodwill ($1,501 and $1,501 related to VIEs)	191,892	191,892
Other intangibles, net	253,486	256,323
Deferred tax asset, net	27,149	26,012
Other non-current assets, net	172	183
Total assets	976,395	961,940
Current liabilities:
Accounts payable ($26,664 and $18,213 related to VIEs)	123,172	137,593
Billings in excess of costs and estimated earnings ($7,443 and $9,649 related to VIEs)	79,293	85,011
Current maturities of long-term debt ($13 and $39 related to VIEs)	50,211	42,473
Current portion of long-term lease obligations ($1,742 and $1,838 related to VIEs)	7,410	7,095
Income taxes payable	1,656	1,212
Accrued compensation ($2,298 and $1,521 related to VIEs)	14,187	13,727
Other current liabilities ($1,097 and $1,429 related to VIEs)	10,403	6,393
Total current liabilities	286,332	293,504
Long-term debt ($2 and $2 related to VIEs)	408,828	390,627
Long-term lease obligations ($2,196 and $1,979 related to VIEs)	7,465	6,976
Members’ interest subject to mandatory redemption and undistributed earnings	49,186	49,003
Other long-term liabilities	5,654	619
Total liabilities	757,465	740,729
Commitments and contingencies (Note 12)
Stockholders’ equity:
Common stock, par value $0.01 per share; 38,000 shares authorized, 28,282 and 28,290 shares issued, 27,966 and 27,772 shares outstanding	283	283
Additional paid in capital	250,689	251,019
Treasury Stock, at cost: 316 and 518 shares	(4,247)	(6,142)
Retained deficit	(21,918)	(25,033)
Accumulated other comprehensive loss	(7,270)	(209)
Total Sterling stockholders’ equity	217,537	219,918
Noncontrolling interests	1,393	1,293
Total stockholders’ equity	218,930	221,211
Total liabilities and stockholders’ equity	$ 976,395	$ 961,940

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	38,000,000	38,000,000
Common stock, shares issued (in shares)	28,282,000	28,290,000
Common stock, shares outstanding (in shares)	27,966,000	27,772,000
Treasury stock (in shares)	316,000	518,000
Cash and cash equivalents ($7,126 and $7,538 related to variable interest entities (“VIEs”))	$ 73,905	$ 45,733
Accounts receivable, including retainage ($30,550 and $24,642 related to VIEs)	221,268	248,247
Costs and estimated earnings in excess of billings ($9,078 and $8,328 related to VIEs)	54,791	42,555
Receivables from and equity in construction joint ventures ($7,729 and $7,406 related to VIEs)	10,789	9,196
Other current assets ($1,047 and $503 related to VIEs)	10,335	11,790
Property and equipment, net ($5,627 and $5,619 related to VIEs)	117,818	116,030
Operating lease right-of-use assets ($3,938 and $3,817 related to VIEs)	14,790	13,979
Goodwill ($1,501 and $1,501 related to VIEs)	191,892	191,892
Accounts payable ($26,664 and $18,213 related to VIEs)	123,172	137,593
Billings in excess of costs and estimated earnings ($7,443 and $9,649 related to VIEs)	79,293	85,011
Current maturities of long-term debt ($13 and $39 related to VIEs)	50,211	42,473
Current portion of long-term lease obligations ($1,742 and $1,838 related to VIEs)	7,410	7,095
Accrued compensation ($2,298 and $1,521 related to VIEs)	14,187	13,727
Other current liabilities ($1,097 and $1,429 related to VIEs)	10,403	6,393
Long-term debt ($2 and $2 related to VIEs)	408,828	390,627
Long-term lease obligations ($2,196 and $1,979 related to VIEs)	7,465	6,976
Variable Interest Entity, Primary Beneficiary
Cash and cash equivalents ($7,126 and $7,538 related to variable interest entities (“VIEs”))	7,126	7,538
Accounts receivable, including retainage ($30,550 and $24,642 related to VIEs)	30,550	24,642
Costs and estimated earnings in excess of billings ($9,078 and $8,328 related to VIEs)	9,078	8,328
Receivables from and equity in construction joint ventures ($7,729 and $7,406 related to VIEs)	7,729	7,406
Other current assets ($1,047 and $503 related to VIEs)	1,047	503
Property and equipment, net ($5,627 and $5,619 related to VIEs)	5,627	5,619
Operating lease right-of-use assets ($3,938 and $3,817 related to VIEs)	3,938	3,817
Goodwill ($1,501 and $1,501 related to VIEs)	1,501	1,501
Accounts payable ($26,664 and $18,213 related to VIEs)	26,664	18,213
Billings in excess of costs and estimated earnings ($7,443 and $9,649 related to VIEs)	7,443	9,649
Current maturities of long-term debt ($13 and $39 related to VIEs)	13	39
Current portion of long-term lease obligations ($1,742 and $1,838 related to VIEs)	1,742	1,838
Accrued compensation ($2,298 and $1,521 related to VIEs)	2,298	1,521
Other current liabilities ($1,097 and $1,429 related to VIEs)	1,097	1,429
Long-term debt ($2 and $2 related to VIEs)	2	2
Long-term lease obligations ($2,196 and $1,979 related to VIEs)	$ 2,196	$ 1,979

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 3,215	$ 1,861
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	8,285	4,302
Amortization of debt issuance costs	1,022	833
Gain on disposal of property and equipment	(393)	(38)
Deferred taxes	913	141
Stock-based compensation expense	2,234	1,021
Unrealized loss on hedge	171	0
Changes in operating assets and liabilities (Note 17)	(4,676)	(27,362)
Net cash provided by (used in) operating activities	10,771	(19,242)
Cash flows from investing activities:
Capital expenditures	(7,354)	(3,814)
Proceeds from sale of property and equipment	512	137
Net cash used in investing activities	(6,842)	(3,677)
Cash flows from financing activities:
Borrowings on revolving credit facility	30,000	0
Repayments of long-term debt	(5,082)	(5,610)
Distributions to noncontrolling interest owners	0	(5,100)
Purchase of treasury stock	0	(3,201)
Other	(675)	(501)
Net cash provided by (used in) financing activities	24,243	(14,412)
Net change in cash and cash equivalents	28,172	(37,331)
Cash and cash equivalents at beginning of period	45,733	94,095
Cash and cash equivalents at end of period	$ 73,905	$ 56,764

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid in Capital	Treasury Stock	Retained Deficit	Accumulated Other Comprehensive Loss	Total Sterling Stockholders’ Equity	Non-controlling Interests
Beginning balance at Dec. 31, 2018	$ 172,260	$ 271	$ 233,795	$ (4,731)	$ (64,934)	$ 0	$ 164,401	$ 7,859
Beginning balance (in shares) at Dec. 31, 2018		26,597		467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,861				1,815		1,815	46
Loss on interest rate swap, net of tax	0
Stock-based compensation (in shares)		(1)
Stock-based compensation	1,021		1,021				1,021
Distributions to owners	(5,100)							(5,100)
Purchase of treasury stock (in shares)		250		250
Purchase of treasury stock	(3,201)			$ (3,201)			(3,201)
Issuance of stock (in shares)		130		(130)
Issuance of stock	0		(1,314)	$ 1,314			0
Shares withheld for taxes (in shares)		52		45
Shares withheld for taxes	(564)			$ (564)			(564)
Ending balance at Mar. 31, 2019	166,277	$ 271	233,502	$ (7,182)	(63,119)	0	163,472	2,805
Ending balance (in shares) at Mar. 31, 2019		26,424		632
Beginning balance at Dec. 31, 2019	221,211	$ 283	251,019	$ (6,142)	(25,033)	(209)	219,918	1,293
Beginning balance (in shares) at Dec. 31, 2019		27,772		518
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,215				3,115		3,115	100
Loss on interest rate swap, net of tax	$ (7,061)					(7,061)	(7,061)
Stock-based compensation (in shares)	138	0
Stock-based compensation	$ 2,234		2,234				2,234
Distributions to owners	0
Issuance of stock (in shares)		248		(248)
Issuance of stock	$ 103		(2,460)	$ 2,563			103
Shares withheld for taxes (in shares)	46	54		46
Shares withheld for taxes	$ (772)		(104)	$ (668)			(772)
Ending balance at Mar. 31, 2020	$ 218,930	$ 283	$ 250,689	$ (4,247)	$ (21,918)	$ (7,270)	$ 217,537	$ 1,393
Ending balance (in shares) at Mar. 31, 2020		27,966		316

Nature of Operations

Nature of Operations	3 Months Ended
	Mar. 31, 2020
Nature of Operations [Abstract]
Nature of Operations	1. NATURE OF OPERATIONS Business Summary Sterling Construction Company, Inc., (“Sterling,” “the Company,” “we,” “our” or “us”), a Delaware corporation, is a construction company that has been involved in the construction industry since its founding in 1955. The Company operates through a variety of subsidiaries within three operating groups specializing in heavy civil, specialty services, and residential projects in the United States (the “U.S.”), primarily across the southern U.S., the Rocky Mountain states, California and Hawaii, as well as other areas with strategic construction opportunities. Heavy civil includes infrastructure and rehabilitation projects for highways, roads, bridges, airfields, ports, light rail, water, wastewater and storm drainage systems. Specialty services projects include construction site excavation and drainage, drilling and blasting for excavation, foundations for multi-family homes, parking structures and other commercial concrete projects. Residential projects include concrete foundations for single-family homes.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	2. BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation Presentation Basis— The accompanying Condensed Financial Statements are presented in accordance with accounting policies generally accepted in the United States (“GAAP”) and reflect all wholly owned subsidiaries and those entities the Company is required to consolidate. See the “Consolidated 50% Owned Subsidiaries” and “Construction Joint Ventures” section of this Note for further discussion of the Company’s consolidation policy for those entities that are not wholly owned. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, considered necessary for a fair presentation have been included. All significant intercompany accounts and transactions have been eliminated in consolidation. Values presented within tables (excluding per share data) are in thousands. Reclassifications have been made to historical financial data in the Condensed Consolidated Financial Statements to conform to the current year presentation. Estimates and Judgments— The preparation of the accompanying Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Certain accounting estimates of the Company require a higher degree of judgment than others in their application. These include the recognition of revenue and earnings from construction contracts over time, the valuation of long-lived assets, goodwill, income taxes, and purchase accounting estimates, including goodwill and other intangible assets. Management continually evaluates all of its estimates and judgments based on available information and experience; however, actual results could differ from these estimates. Significant Accounting Policies Revenue Recognition— Our revenue is derived from long-term contracts for customers in our heavy civil and specialty services business segments, as well as short-term projects for customers in our residential business segment. Accounting treatment for these contracts in accordance with Accounting Standards Update (“ASU”) 2014-09 (Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers ) , is as follows: • Performance Obligations Satisfied Over Time (Heavy Civil and Specialty Services) Recognition of Performance Obligations— A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account in the new revenue standard. The contract transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. Heavy civil projects typically span between 12 to 36 months , and specialty services projects are between 6 to 24 months . The majority of our contracts have a single performance obligation as the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts and, therefore, not distinct. Some contracts have multiple performance obligations, most commonly due to the contract covering multiple phases of the project life cycle (design and construction). Revenues are recognized as our obligations are satisfied over time, using the ratio of project costs incurred to estimated total costs for each contract because of the continuous transfer of control to the customer as all of the work is performed at the customer’s site and, therefore, the customer controls the asset as it is being constructed. This continuous transfer of control to the customer is further supported by clauses in the contract that allow the customer to unilaterally terminate the contract for convenience, pay the Company for costs incurred plus a reasonable profit and take control of any work in process. 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. Items excluded from cost-to-cost— Pre-contract costs are generally not material and are charged to expense as incurred, but in certain cases pre-contract recognition may be deferred if specific probability criteria are met. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Remaining Performance Obligations (“RPOs”)— RPOs represent the amount of revenues we expect to recognize in the future from our contract commitments on projects and are hereafter referred to as “Backlog”. Backlog includes the entire expected revenue values for joint ventures we consolidate and our proportionate value for those we proportionately consolidate. Backlog may not be indicative of future operating results, and projects included in Backlog may be canceled, modified or otherwise altered by customers. See Note 4 - Revenue from Customers , for further discussion. Variable Consideration— Contract modifications through change orders, claims and incentives are routine in the performance of the Company’s contracts to account for changes in the contract specifications or requirements. In most instances, contract modifications are not distinct from the existing contract due to the significant integration of services provided in the contract and are accounted for as a modification of the existing contract and performance obligation. Either the Company or its customers may initiate change orders, which may include changes in specifications or designs, manner of performance, facilities, equipment, materials, sites and period of completion of the work. 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 the Company seeks to collect from its 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. The Company estimates variable consideration for a performance obligation at the most likely amount to which the Company expects to be entitled (or the most likely amount the Company expects to incur in the case of liquidated damages), utilizing estimation methods that best predict the amount of consideration to which the Company will be entitled (or will be incurred in the case of liquidated damages). The Company includes variable consideration in the estimated transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur or when the uncertainty associated with the variable consideration is resolved. The Company’s estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of its anticipated performance and all information (historical, current and forecasted) that is reasonably available to the Company. The effect of variable consideration on the transaction price of a performance obligation is recognized as an adjustment to revenue on a cumulative catch-up basis. To the extent unapproved change orders and claims reflected in the transaction price (or excluded from the transaction price in the case of liquidated damages) are not resolved in the Company’s favor, or to the extent incentives reflected in the transaction price are not earned, there could be reductions in, or reversals of, previously recognized revenue. • Performance Obligations Satisfied at a Point-in-Time (Residential) Revenue for our residential contracts is recognized at a point in time and utilizes an output measure for performance based on the completion of a unit of work (e.g. completion of concrete foundation). The time from starting construction to completion is typically two weeks or less. Upon fulfillment of the performance obligation, the customer is provided an invoice (or equivalent) demonstrating transfer of control to the customer. Receivables, including Retainage— Receivables are generally based on amounts billed to the customer in accordance with contractual provisions. Many of the contracts under which the Company performs work also contain retainage provisions. Retainage refers to that portion of our billings 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. At March 31, 2020 and December 31, 2019 , receivables included $73,400 and $79,400 of retainage. 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 March 31, 2020 and December 31, 2019 , our allowance for doubtful accounts against contracts receivable was zero . 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. Contracts in Progress— The timing of revenue recognition, billings and costs incurred results in billed accounts receivable and costs and estimated earnings in excess of billings on uncompleted contracts (contract assets) on the Condensed Consolidated Balance Sheet. For performance obligations satisfied over time, amounts are billed as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals (e.g., biweekly or monthly) or upon achievement of contractual milestones. Typically, Sterling bills for advances or deposits from its customers, before revenue is recognized, resulting in billings in excess of costs and estimated earnings on uncompleted contracts (contract liabilities). However, the Company occasionally bills subsequent to revenue recognition, resulting in contract assets. These assets and liabilities are reported on the Condensed Consolidated Balance Sheet on a contract-by-contract basis at the end of each reporting period. Consolidated 50% Owned Subsidiaries— The Company has 50% ownership interests in two subsidiaries that it fully consolidates as a result of its exercise of control of the entities. The results attributable to the 50% portions that the Company does not own are eliminated within “Other operating expense, net” within the Condensed Consolidated Statements of Operations and an associated liability is established within “Members’ interest subject to mandatory redemption and undistributed earnings” within the Condensed Consolidated Balance Sheets. These subsidiaries also have individual mandatory redemption provisions which, under circumstances that are certain to occur, obligate the Company to purchase the remaining 50% interests. These purchase obligations are also recorded in “Members’ interest subject to mandatory redemption and undistributed earnings” on the Condensed Consolidated Balance Sheets. Construction Joint Ventures— In the ordinary course of business, the Company executes specific projects and conducts certain operations through joint venture arrangements (referred to as “joint ventures”). The Company has various ownership interests in these joint ventures, with such ownership typically proportionate to the Company’s decision making and distribution rights. Each joint venture is assessed at inception and on an ongoing basis as to whether it qualifies as a Variable Interest Entity (“VIE”) under the consolidations guidance in ASC Topic 810. If at any time a joint venture qualifies as a VIE, the Company performs a qualitative assessment to determine whether the Company is the primary beneficiary of the VIE and therefore needs to consolidate the VIE. If the Company determines it is not the primary beneficiary of the VIE or only has the ability to significantly influence, rather than control the joint venture, it is not consolidated. The Company accounts for unconsolidated joint ventures using a pro-rata basis in the Condensed Consolidated Statements of Operations and as a single line item (“Receivables from and equity in construction joint ventures”) in the Condensed Consolidated Balance Sheets. This method is a permissible modification of the equity method of accounting which is a common practice in the construction industry. Cash and Restricted cash— Our cash is comprised of highly liquid investments with maturities of three months or less. Restricted cash of approximately $4,700 and $4,800 is included in “Other current assets” on the Condensed Consolidated Balance Sheets at March 31, 2020 and December 31, 2019 . This primarily represents cash deposited by the Company into separate accounts and designated as collateral for standby letters of credit in the same amount in accordance with contractual agreements. 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 20 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. See Note 7 - Property and Equipment for disclosure of the components of property and equipment. Lease Arrangements— In the ordinary course of business, the Company enters into a variety of lease arrangements, including operating and finance leases. • Operating & Finance Leases— The Company determines if an arrangement is a lease at inception. The operating lease right-of-use (“ROU”) assets are included within the Company’s non-current assets and lease liabilities are included in current or non-current liabilities on the Company’s Condensed Consolidated Balance Sheets. Finance leases are included in “Property and equipment”, “Current maturities of long-term debt”, and “Long-term debt” on the Company’s Condensed Consolidated Balance Sheets. ROU assets represent the Company’s right to use, or control the use of, a specified asset for the lease term. Lease liabilities are the Company’s obligation to make lease payments arising from a lease, and are measured on a discounted basis. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term on the commencement date. As most of the Company’s leases do not provide an implicit rate, the Company’s incremental borrowing rate was used based on the information available on the commencement date in determining the present value of lease payments. For future leases, the implied rate in the lease will be used to determine the present value. The operating lease ROU asset includes any lease payments made and initial direct costs incurred and excludes lease incentives. 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 continues to be recognized on a straight-line basis over the lease term. Goodwill— Goodwill represents the excess of the cost of companies acquired over the fair value of their net assets at the dates of acquisition. Goodwill is not amortized, but instead is reviewed for impairment at least annually at a reporting unit level, absent any interim indicators of impairment. Interim testing for impairment is performed if indicators of potential impairment exist. We perform our annual impairment assessment during the fourth quarter of each year. We identify a potential impairment by comparing the fair value of the applicable reporting unit to its net book value, including goodwill. To determine the fair value of our reporting units and test for impairment, we utilize an income approach (discounted cash flow method) as we believe this is the most direct approach to incorporate the specific economic attributes and risk profiles of our reporting units into our valuation model. We generally do not utilize a market approach, given the lack of relevant information generated by market transactions involving comparable businesses. However, to the extent market indicators of fair value become available, we consider such market indicators in our discounted cash flow analysis and determination of fair value. Evaluating Impairment of Other Intangible Assets and Other Long-Lived Assets— Our finite-lived intangible assets are amortized over their estimated remaining useful economic lives. Our project-related intangible assets are amortized as the applicable projects progress, customer relationships are amortized utilizing an accelerated method based on the pattern of cash flows expected to be realized, taking into consideration expected revenues and customer attrition, and our other intangibles are amortized utilizing a straight-line method. When events or changes in circumstances indicate that finite-lived intangible and other long-lived assets may be impaired, an evaluation is performed. If the asset or asset group fails the recoverability test, we will perform a fair value measurement to determine and record an impairment charge. See Note 8 - Other Intangible Assets for further discussion. 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 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 13 - Income Taxes for further information regarding our federal and state income taxes. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13 to add the guidance in ASC 326 on the impairment of financial instruments. The ASU introduces an impairment model (known as the current expected credit loss (CECL) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The ASU is also intended to reduce the complexity of U.S. GAAP by decreasing the number of credit impairment models that entities use to account for debt instruments. The amendments in the ASU are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2020 as required and noted no material impact to the Company’s Condensed Consolidated Financial Statements.

Plateau Acquisition

Plateau Acquisition	3 Months Ended
	Mar. 31, 2020
Business Combinations [Abstract]
Plateau Acquisition	3. PLATEAU ACQUISITION General— On October 2, 2019, pursuant to the Equity Purchase Agreement with Greg K. Rogers, Philip T. Travis, as trustee of the Lorin L. Rogers 2018 Trust, Kimberlin Rogers 2018 Trust, Gregory K. Rogers 2018 Trust and Mary A. Rogers 2018 Trust, as well as LK Gregory Construction, Inc., Plateau Excavation, Inc. and DeWitt Excavation, LLC (collectively “Plateau”), Sterling consummated the acquisition (the “Plateau Acquisition”) of all of the issued and outstanding shares of capital stock of LK Gregory Construction, Inc. and Plateau Excavation, Inc., and all of the issued and outstanding equity interests in DeWitt Excavation, LLC. Plateau is engaged in the business of surveying, clearing and grubbing, erosion control, grading, grassing, site excavation, storm drainage, sanitary sewer and water main installation, drilling and blasting, curb and gutter, paving, concrete work and landfill services, in each case to general contractors and developers engaged in construction services, and engineering services relating thereto. Acquisition Accounting— The Plateau Acquisition is accounted for using the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations . Purchase Consideration— Sterling completed the Plateau Acquisition for a purchase price of $427,659 , net of cash acquired, detailed as follows: Cash consideration transferred, net of $2,425 of cash acquired $ 375,000 Target working capital adjustment 21,323 Equity consideration transferred (1,245 shares at $13.01 per share (1) ) 16,195 Note payable to seller (See Note 9 - Debt) 10,000 Estimated tax basis election 5,141 Total consideration $ 427,659 (1) Sterling’s closing stock price on October 1, 2019 Preliminary Purchase Price Allocation— The aggregate purchase price noted above was allocated to the assets and liabilities acquired based upon their estimated fair values at the acquisition closing date, which were based, in part, upon external preliminary appraisal and valuation of certain assets, including specifically identified intangible assets. The excess of the purchase price over the preliminary estimated fair value of the net tangible and identifiable intangible assets acquired totaling $106,661 , was recorded as goodwill. The following table summarizes our purchase price allocation at the acquisition closing date, net of cash acquired: Net tangible assets: Accounts receivable, including retainage $ 81,921 Costs and estimated earnings in excess of billings 974 Other current assets 249 Property and equipment, net 65,492 Other non-current assets, net 10 Accounts payable (22,039 ) Billings in excess of costs and estimated earnings (16,540 ) Other current liabilities (7,669 ) Total net tangible assets 102,398 Identifiable intangible assets 218,600 Goodwill 106,661 Total consideration transferred $ 427,659 The purchase price allocation above is subject to further change when additional information is obtained. We have not finalized our assessment of the fair values primarily for intangible assets and property and equipment. We intend to finalize the purchase price allocation as soon as practicable within the measurement period, but in no event later than one year following the closing date of the Plateau Acquisition. Our final purchase price allocation may result in additional adjustments to various other assets and liabilities, including the residual amount allocated to goodwill during the measurement period. Identifiable Intangible Assets — Intangible assets identified as part of the Plateau Acquisition are reflected in the table below and are recorded at their estimated fair value, as determined by the Company’s management, based on available information which includes a preliminary valuation from external experts. The estimated useful lives for intangible assets were determined based upon the remaining useful economic lives of the intangible assets that are expected to contribute directly or indirectly to future cash flows. Weighted Average Life (Years) October 2, 2019 Fair Value Customer relationships 25 $ 191,800 Trade name 25 24,800 Non-compete agreements 5 2,000 Total $ 218,600 Supplemental Pro Forma Information (Unaudited) — The following unaudited pro forma combined financial information (“the pro forma financial information”) gives effect to the Plateau Acquisition, accounted for as a business combination using the purchase method of accounting. The pro forma financial information reflects the Plateau Acquisition and related events as if they occurred at the beginning of the period, and gives effect to pro forma events that are: directly attributable to the acquisition, factually supportable and expected to have a continuing impact on the combined results of Sterling and Plateau following the Plateau Acquisition. The pro forma financial information includes adjustments to: (1) exclude transaction costs that were included in historical results and are expected to be non-recurring, (2) include additional intangibles amortization and net interest expense associated with the Plateau Acquisition and (3) include the pro forma results of Plateau for the period ended March 31, 2019 . This pro forma financial information has been presented for illustrative purposes only and is not necessarily indicative of the operating results that would have been achieved had the pro forma events taken place on the dates indicated. Further, the pro forma financial information does not purport to project the future operating results of the combined company following the Plateau Acquisition. Three Months Ended March 31, 2019 Pro forma revenue $ 282,609 Pro forma net income attributable to Sterling $ 7,331

Revenue From Contracts With Cus

Revenue From Contracts With Customers	3 Months Ended
	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue From Customers	4. REVENUE FROM CUSTOMERS Backlog The Company had the following backlog, by segment: March 31, December 31, Heavy Civil Backlog $ 886,575 $ 834,049 Specialty Services Backlog 303,545 233,976 Total Heavy Civil and Specialty Services Backlog $ 1,190,120 $ 1,068,025 The Company expects to recognize approximately 65% of its backlog as revenue during the next twelve months , and the balance thereafter. Revenue Disaggregation The following tables present the Company’s revenue disaggregated by major end market and contract type: Three Months Ended March 31, Revenue by major end market 2020 2019 Heavy Highway $ 96,374 $ 93,610 Aviation 28,457 29,937 Water Containment and Treatment 21,809 15,234 Other 8,975 11,724 Heavy Civil Revenue $ 155,615 $ 150,505 Land Development $ 76,245 $ — Commercial 28,478 30,679 Specialty Services Revenue $ 104,723 $ 30,679 Residential Revenue $ 36,350 $ 42,765 Revenues $ 296,688 $ 223,949 Revenue by contract type Fixed-Unit Price $ 141,739 $ 141,219 Lump Sum 114,252 39,132 Residential and Other 40,697 43,598 Revenues $ 296,688 $ 223,949 Each of these contract types presents advantages and disadvantages. Typically, the Company assumes more risk with lump-sum contracts. However, these types of contracts offer additional profits if the work is completed for less than originally estimated. Under fixed-unit price contracts, the Company’s profit may vary if actual labor-hour costs vary significantly from the negotiated rates. Also, because some contracts can provide little or no fee for managing material costs, the components of contract cost can impact profitability. Variable Consideration The Company has projects that it is in the process of negotiating, or awaiting final approval of, unapproved change orders and claims with its 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 the Company’s 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 the Company’s review of the provisions of its contracts, specific costs incurred and other related evidence supporting the unapproved change orders and claims, together in some cases as necessary with the views of the Company’s outside claim consultants, the Company concluded it was appropriate to include in project price amounts of $7,100 and $3,000 , at March 31, 2020 and December 31, 2019 , respectively. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Contract Estimates Accounting for long-term contracts and programs involves the use of various techniques to estimate total contract revenue and costs. For long-term contracts, the Company estimates the profit on a contract as the difference between the total estimated revenue and expected costs to complete a contract and recognizes such profit over the life of the contract. Contract estimates are based on various assumptions to project the outcome of future events that often span several years. These assumptions include labor productivity and availability, the complexity of the work to be performed, the cost and availability of materials and the performance of subcontractors. Changes in job performance, job conditions and estimated profitability, 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. Changes in estimated revenues and gross margin resulted in a net increase of $95 for the three months ended March 31, 2020 , and net decrease of $200 for the three months ended March 31, 2019 , included in “Operating income” on the Condensed Consolidated Statements of Operations.

Consolidated 50% Owned Subsidia

Consolidated 50% Owned Subsidiaries	3 Months Ended
	Mar. 31, 2020
Noncontrolling Interest [Abstract]
Consolidated 50% Owned Subsidiaries	5. CONSOLIDATED 50% OWNED SUBSIDIARIES The Company has 50% ownership interests in two subsidiaries (“Myers” and “RHB”) that it fully consolidates as a result of its exercise of control over the entities. The earnings attributable to the 50% portions the Company does not own were $1,700 and $1,300 for the three months ended March 31, 2020 and 2019 , respectively, and are eliminated within “Other operating expense, net” in the Condensed Consolidated Statements of Operations. Any undistributed earnings for partners are included in “Members’ interest subject to mandatory redemption and undistributed earnings” within the Condensed Consolidated Balance Sheets and are mandatorily payable at the time of the noncontrolling owners’ death or permanent disability. These two subsidiaries have individual mandatory redemption provisions which, under circumstances outlined in the partner agreements, are certain to occur and obligate the Company to purchase each partner’s remaining 50% interests for $20,000 ( $40,000 in the aggregate). The Company has purchased two separate $20,000 death and permanent total disability insurance policies to mitigate the Company’s cash draw if such events were to occur. These purchase obligations are recorded in “Members’ interest subject to mandatory redemption and undistributed earnings” on the Condensed Consolidated Balance Sheets. The liability consists of the following: March 31, December 31, Members’ interest subject to mandatory redemption $ 40,000 $ 40,000 Net accumulated earnings 9,186 9,003 Total liability $ 49,186 $ 49,003 The Company must determine whether any of its entities, including these two 50% owned subsidiaries, in which it participates, is a variable interest entity (“VIE”). The Company determined Myers is a VIE, as the Company is the primary beneficiary, as pursuant to the terms of the Myers Operating Agreement the Company is exposed to the majority of potential losses of the partnership. Summary financial information for Myers is as follows: Three Months Ended March 31, 2020 2019 Revenues $ 44,362 $ 42,414 Operating income $ 155 $ 277 Net income $ 158 $ 282

Construction Joint Ventures

Construction Joint Ventures	3 Months Ended
	Mar. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Construction Joint Ventures	6. CONSTRUCTION JOINT VENTURES The Company participates in joint ventures with other major construction companies and other partners, typically for large, technically complex projects, including design-build projects, when it is desirable to share risk and resources in order to seek a competitive advantage. Joint venture partners typically provide independently prepared estimates, furnish employees and equipment, enhance bonding capacity and often also bring local knowledge and expertise. These projects generally have joint and several liability. The Company selects its joint venture partners based on its analysis of their construction and financial capabilities, expertise in the type of work to be performed and past working relationships with the Company, among other criteria. Joint ventures with a controlling interest —For these joint ventures, the equity held by the remaining owners and their portions of net income (loss) are reflected in the Condensed Consolidated Balance Sheets line item “Noncontrolling interests” in “Stockholders’ equity” and the Condensed Consolidated Statements of Operations line item “Net income attributable to noncontrolling interests,” respectively. The following table summarizes the changes in the noncontrolling owners’ interests in subsidiaries and consolidated joint ventures: Three Months Ended March 31, 2020 2019 Balance, beginning of period $ 1,293 $ 7,859 Net income attributable to noncontrolling interest 100 46 Distributions to noncontrolling interest owners — (5,100 ) Balance, end of period $ 1,393 $ 2,805 Joint ventures with a noncontrolling interest —Where the Company has a noncontrolling joint interest in a venture, the Company accounts for its share of the operations of such construction joint ventures on a pro-rata basis using proportionate consolidation on its Condensed Consolidated Statements of Operations and as a single line item in “ Receivables from and equity in construction joint ventures ” in the Condensed Consolidated Balance Sheets. This method is an acceptable modification of the equity method of accounting which is a common practice in the construction industry. Condensed combined financial amounts of joint ventures in which the Company has a noncontrolling interest and the Company’s share of such amounts which are included in the Company’s Condensed Consolidated Financial Statements are shown below: March 31, December 31, Current assets $ 60,517 $ 92,710 Current liabilities $ (77,164 ) $ (86,705 ) Sterling’s receivables from and equity in construction joint ventures $ 10,789 $ 9,196 Three Months Ended March 31, 2020 2019 Revenues $ 26,846 $ 31,384 Income before tax $ 2,157 $ 1,969 Sterling’s noncontrolling interest: Revenues $ 13,082 $ 15,684 Income before tax $ 1,049 $ 984 The caption “ Receivables from and equity in construction joint ventures ,” includes undistributed earnings and receivables owed to the Company. Undistributed earnings are typically released to the joint venture partners after the customer accepts the project as completed and the warranty period, if any, has passed. The Company must determine whether each joint venture in which it participates is a variable interest entity. This determination focuses on identifying which joint venture partner, if any, has the power to direct the activities of a joint venture and the obligation to absorb losses of the joint venture or the right to receive benefits from the joint venture in excess of their ownership interests and could have the effect of requiring us to consolidate joint ventures in which we have a noncontrolling variable interest. The Company determined that the joint venture between RLW ( 51% owner) and SEMA Construction Inc (“SEMA”) ( 49% owner) is a VIE as the Company is the primary beneficiary, as pursuant to the terms of the SEMA Operating Agreement the Company is exposed to 51% of potential losses of the partnership. Summary financial information for SEMA is as follows: Three Months Ended March 31, 2020 2019 Revenues $ 4,064 $ 602 Operating income $ 296 $ 38 Net income $ 299 $ 38

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	7. PROPERTY AND EQUIPMENT Property and equipment are summarized as follows: March 31, December 31, Construction and transportation equipment $ 221,336 $ 217,945 Buildings and improvements 15,711 14,641 Land 3,891 3,891 Office equipment 2,607 2,767 Total property and equipment 243,545 239,244 Less accumulated depreciation (125,727 ) (123,214 ) Total property and equipment, net $ 117,818 $ 116,030 Depreciation Expense— Depreciation expense is primarily included within cost of revenues and was $5,448 and $3,702 for the three months ended March 31, 2020 and 2019 , respectively.

Other Intangible Assets

Other Intangible Assets	3 Months Ended
	Mar. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	8. OTHER INTANGIBLE ASSETS The following table presents the Company’s acquired finite-lived intangible assets at March 31, 2020 and December 31, 2019 : March 31, 2020 December 31, 2019 Weighted Gross Gross Customer relationships 25 years $ 232,623 $ (9,251 ) $ 232,623 $ (6,911 ) Trade name 23 years 30,107 (2,071 ) 30,107 (1,692 ) Non-competition agreements 5 years 2,487 (409 ) 2,487 (291 ) Total 24 years $ 265,217 $ (11,731 ) $ 265,217 $ (8,894 ) The Company's intangible amortization expense was $2,837 and $600 for the three months ended March 31, 2020 and 2019 , respectively.

Debt

Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Debt	9. DEBT The Company’s outstanding debt was as follows: March 31, December 31, Term Loan Facility $ 395,000 $ 400,000 Revolving Credit Facility 50,000 20,000 Credit Facility 445,000 420,000 Note payable to seller, Plateau Acquisition 10,000 10,000 Notes and deferred payments to sellers, Tealstone Acquisition 12,500 12,230 Notes payable for transportation and construction equipment and other 723 805 Total debt 468,223 443,035 Less - Current maturities of long-term debt (50,211 ) (42,473 ) Less - Unamortized debt issuance costs (9,184 ) (9,935 ) Total long-term debt $ 408,828 $ 390,627 Credit Facility —On October 2, 2019, the Company, as borrower, and certain of its subsidiaries, as guarantors, entered into a Credit Agreement (the “Credit Agreement”) with BMO Harris Bank N.A., as administrative agent (the “Agent”), Bank of America, N.A., as syndication agent, and BMO Capital Markets Corp. and BofA Securities, Inc., as joint lead arrangers and joint book runners. The Credit Agreement provides the Company with senior secured debt financing in an amount up to $475,000 in the aggregate, consisting of (i) a senior secured first lien revolving credit facility (the “Revolving Credit Facility”) in an aggregate principal amount of $75,000 (with a $75,000 limit for the issuance of letters of credit and a $15,000 sublimit for swing line loans) and (ii) a senior secured first lien term loan facility (the “ Term Loan Facility ”) in the amount of $400,000 (collectively, the “Credit Facility”). The obligations under the Credit Facility are secured by substantially all assets of the Company and the subsidiary guarantors, subject to certain permitted liens and interests of other parties. The Credit Facility will mature on October 2, 2024. The Revolving Credit Facility bears interest at either the Base Rate plus a margin ( 4.25% and 3.50% per annum, respectively at March 31, 2020 ), or one-, two-, three-, six- or, if available, twelve-month LIBOR plus an applicable margin ( 0.93% and 4.50% per annum, respectively at March 31, 2020 , using a one-month LIBOR rate), at the Company’s election. In addition to interest on debt borrowings, we are assessed quarterly commitment fees on the unutilized portion of the facility as well as letter of credit fees on outstanding instruments. Interest under the Revolving Credit Facility is payable (i) with respect to LIBOR borrowings, on the last day of each applicable interest period (one, two, three, six or twelve months), unless the applicable interest period is longer than three months, then on each day occurring every three months after the commencement of such interest period, and on the maturity date, and (ii) with respect to Base Rate borrowings, on the last day of every calendar quarter and on the maturity date. At March 31, 2020 , we had $50,000 of outstanding borrowings under the facility, providing $25,000 of available capacity. During the three months ended March 31, 2020 , our weighted average interest rate on borrowings under the facility was approximately 6.17% . The Revolving Credit Facility may be repaid in whole or in part at any time, with final payment of all principal and interest then outstanding due on October 2, 2024. Interest under the Term Loan Facility is payable at the same frequencies and bears interest at the same rate options as the Revolving Credit Facility. In connection with entering into the Credit Facility, on December 5, 2019 we entered into an interest rate swap to hedge against $350,000 of the outstanding Term Loan Facility, which resulted in a weighted average interest rate of approximately 6.05% per annum during the three months ended March 31, 2020 . At March 31, 2020 , we had $395,000 of outstanding borrowings under the facility. Principal payments on the Term Loan Facility total $30,000 , $50,000 , $50,000 , $50,000 and $220,000 for each of the years ending 2020, 2021, 2022, 2023, and 2024, respectively. A final payment of all principal and interest then outstanding on the Term Loan Facility is due on October 2, 2024. The Credit Agreement contains various affirmative and negative covenants that may, subject to certain exceptions, restrict the ability of us and our subsidiaries to, among other things, grant liens, incur additional indebtedness, make loans, advances or other investments, make non-ordinary course asset sales, declare or pay dividends or make other distributions with respect to equity interests, purchase, redeem or otherwise acquire or retire capital stock or other equity interests, or merge or consolidate with any other person, among various other things. In addition, the Company is required to maintain the following financial covenants: • a Total Leverage Ratio (as defined in the Credit Agreement) at the last day of each fiscal quarter not to be greater than 4.00 to 1.00 ending on December 31, 2019 through and including June 30, 2020, 3.75 to 1.00 ending on September 30, 2020, 3.50 to 1.00 ending on December 31, 2020 through and including March 31, 2021, 3.25 to 1.00 ending on June 30, 2021 through and including September 30, 2021, and 3.00 to 1.00 ending on December 31, 2021 and thereafter; and • a Fixed Charge Coverage Ratio (as defined in the Credit Agreement) of not less than 1.20 to 1.00 as of the last day of each fiscal quarter of the Company, commencing with the fiscal quarter ending December 31, 2019. Debt issuance costs —The Company incurred $10,688 of fees relating to the establishment of the Credit Facility in 2019 . The costs associated with the Term Loan Facility and Revolving Credit Facility are reflected on the Balance Sheets as a direct reduction from the related debt liability and amortized over the terms of the respective facilities. Amortization of debt issuance costs was $752 and $833 for the three months ended March 31, 2020 and 2019 , respectively, and was recorded as interest expense. Note Payable to Seller, Plateau Acquisition —As part of the Plateau Acquisition, the Company issued a $10,000 subordinated promissory note to one of the Plateau sellers that bears interest at 8% with interest payments due quarterly beginning January 1, 2020. The subordinated promissory note has no scheduled payments, however, it may be repaid in whole or in part at any time, subject to certain payment restrictions under a subordination agreement with the Agent under our Credit Agreement, without premium or penalty, with final payment of all principal and interest then outstanding due on April 2, 2025. Notes and deferred Payments to Sellers, Tealstone Acquisition— At March 31, 2020 the Company had $12,500 outstanding, net of debt discounts, of the combined promissory notes and deferred cash payments issued as part of the Tealstone Acquisition. During the three months ended March 31, 2020 , the Company did not make any deferred cash payments. The remaining principal amounts of $5,000 of promissory notes and $7,500 of deferred cash payments are due on April 3, 2020. Notes Payable for Transportation and Construction Equipment and Other —The Company has purchased and financed various construction and transportation equipment to enhance the Company’s fleet of equipment. The total long-term notes payable related to the purchase of financed equipment was $723 and $805 at March 31, 2020 and December 31, 2019 , respectively. The purchases have payment terms ranging from 3 to 5 years and the associated interest rates range from 2.99% to 6.92% . Compliance and other —As of March 31, 2020 , we were in compliance with all of our restrictive and financial covenants. The Company’s debt is recorded at its carrying amount in the Condensed Consolidated Balance Sheets. As of March 31, 2020 and December 31, 2019 , the carrying values of our debt outstanding approximated the fair values.

Lease Obligations

Lease Obligations	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Lease Obligations	10. LEASE OBLIGATIONS The Company has operating and finance leases primarily for construction and transportation equipment, as well as office space. The Company’s leases have remaining lease terms of 1 month to 5 years , some of which include options to extend the leases for up to 10 years . The components of lease expense were as follows: Three Months Ended March 31, 2020 2019 Operating lease cost $ 2,159 $ 2,211 Short-term lease cost $ 3,281 $ 4,743 Finance lease cost: Amortization of right-of-use assets $ 56 $ 32 Interest on lease liabilities 8 2 Total finance lease cost $ 64 $ 34 Supplemental cash flow information related to leases was as follows: Three Months Ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,105 $ 2,383 Operating cash flows from finance leases $ 8 $ 2 Financing cash flows from finance leases $ 56 $ 32 Right-of-use assets obtained in exchange for lease obligations (noncash): Operating leases $ 3,540 $ 3,101 Finance leases $ — $ 76 Supplemental balance sheet information related to leases was as follows: March 31, December 31, Operating Leases Operating lease right-of-use assets $ 14,790 $ 13,979 Current portion of long-term lease obligations $ 7,410 $ 7,095 Long-term lease obligations 7,465 6,976 Total operating lease liabilities $ 14,875 $ 14,071 Finance Leases Property and equipment, at cost $ 1,479 $ 1,479 Accumulated depreciation (537 ) (482 ) Property and equipment, net $ 942 $ 997 Current maturities of long-term debt $ 198 $ 204 Long-term debt 509 560 Total finance lease liabilities $ 707 $ 764 Weighted Average Remaining Lease Term Operating leases 2.6 2.5 Finance leases 3.9 4.0 Weighted Average Discount Rate Operating leases 6.0 % 6.0 % Finance leases 4.2 % 4.2 % Maturities of lease liabilities are as follows: Operating Leases Finance Leases Year Ending December 31, 2020 (excluding the three months ended March 31, 2020) $ 5,159 $ 168 2021 5,720 208 2022 3,768 161 2023 1,624 154 2024 198 77 Thereafter 11 — Total lease payments $ 16,480 $ 768 Less imputed interest (1,605 ) (61 ) Total $ 14,875 $ 707
Lease Obligations	10. LEASE OBLIGATIONS The Company has operating and finance leases primarily for construction and transportation equipment, as well as office space. The Company’s leases have remaining lease terms of 1 month to 5 years , some of which include options to extend the leases for up to 10 years . The components of lease expense were as follows: Three Months Ended March 31, 2020 2019 Operating lease cost $ 2,159 $ 2,211 Short-term lease cost $ 3,281 $ 4,743 Finance lease cost: Amortization of right-of-use assets $ 56 $ 32 Interest on lease liabilities 8 2 Total finance lease cost $ 64 $ 34 Supplemental cash flow information related to leases was as follows: Three Months Ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,105 $ 2,383 Operating cash flows from finance leases $ 8 $ 2 Financing cash flows from finance leases $ 56 $ 32 Right-of-use assets obtained in exchange for lease obligations (noncash): Operating leases $ 3,540 $ 3,101 Finance leases $ — $ 76 Supplemental balance sheet information related to leases was as follows: March 31, December 31, Operating Leases Operating lease right-of-use assets $ 14,790 $ 13,979 Current portion of long-term lease obligations $ 7,410 $ 7,095 Long-term lease obligations 7,465 6,976 Total operating lease liabilities $ 14,875 $ 14,071 Finance Leases Property and equipment, at cost $ 1,479 $ 1,479 Accumulated depreciation (537 ) (482 ) Property and equipment, net $ 942 $ 997 Current maturities of long-term debt $ 198 $ 204 Long-term debt 509 560 Total finance lease liabilities $ 707 $ 764 Weighted Average Remaining Lease Term Operating leases 2.6 2.5 Finance leases 3.9 4.0 Weighted Average Discount Rate Operating leases 6.0 % 6.0 % Finance leases 4.2 % 4.2 % Maturities of lease liabilities are as follows: Operating Leases Finance Leases Year Ending December 31, 2020 (excluding the three months ended March 31, 2020) $ 5,159 $ 168 2021 5,720 208 2022 3,768 161 2023 1,624 154 2024 198 77 Thereafter 11 — Total lease payments $ 16,480 $ 768 Less imputed interest (1,605 ) (61 ) Total $ 14,875 $ 707

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	11. FINANCIAL INSTRUMENTS Derivatives Interest Rate Derivative —On December 5, 2019 , the Company entered into a three year interest rate swap agreement with Bank of America in order to mitigate exposure to the market risk associated with the variable interest on the $400,000 term loan. The Company has designated its interest rate swap agreement as a cash flow hedging derivative. To the extent the derivative instrument is effective and the documentation requirements have been met, changes in fair value are recognized in other comprehensive income until the underlying hedged item is recognized in earnings. As of March 31, 2020 , the notional value of the swap contract was $350,000 and the fair value of the swap contract was a loss of $9,524 . We utilized Level 2 inputs in the fair value hierarchy of valuation techniques to determine the fair value of the swap contract. Financial Instruments Disclosures Fair Value —Financial instruments are required to be categorized within a valuation hierarchy based upon the lowest level of input that is significant to the fair value measurement. The three levels of the valuation hierarchy are as follows: • Level 1—Fair value is based on quoted prices in active markets. • Level 2—Fair value is based on internally developed models that use, as their basis, readily observable market parameters. Our derivative positions are classified within level 2 of the valuation hierarchy as they are valued using quoted market prices for similar assets and liabilities in active markets. These level 2 derivatives are valued utilizing an income approach, which discounts future cash flow based on current market expectations and adjusts for credit risk. • Level 3—Fair value is based on internally developed models that use, as their basis, significant unobservable market parameters. The Company did not have any level 3 classifications at March 31, 2020 or December 31, 2019 . The following table presents the fair value of the interest rate derivative by valuation hierarchy and balance sheet classification: March 31, 2020 December 31, 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Derivative Assets Other current assets $ — $ — $ — $ — $ — $ 216 $ — $ 216 Other non-current assets — — — — — — — — Total assets at fair value $ — $ — $ — $ — $ — $ 216 $ — $ 216 Derivative Liabilities Other current liabilities $ — $ (4,086 ) $ — $ (4,086 ) $ — $ (61 ) $ — $ (61 ) Other non-current liabilities — (5,438 ) — (5,438 ) — (398 ) — (398 ) Total liabilities at fair value $ — $ (9,524 ) $ — $ (9,524 ) $ — $ (459 ) $ — $ (459 ) The carrying values of the Company's cash and cash equivalents (primarily consisting of bank deposits), accounts receivable and accounts payable approximate their fair values because of the short-term nature of these instruments. At March 31, 2020 , the fair value of the term loan, based upon the current market rates for debt with similar credit risk and maturities, approximated its carrying value as interest is based on LIBOR plus an applicable margin. Derivatives Disclosures AOCI/Other —The following table presents the change in other comprehensive income (“OCI”) during the three months ended March 31, 2020 for derivatives designated as cash flow hedges: Before Tax Amount Tax Amount Net of Tax Amount Net gain (loss) recognized in OCI $ (9,174 ) $ 2,064 $ (7,110 ) Net amount reclassified from AOCI into earnings (1) 63 (14 ) 49 Change in OCI $ (9,111 ) $ 2,050 $ (7,061 ) (1) Net unrealized losses totaling $3,946 are anticipated to be reclassified from AOCI into interest expense during the next 12 months due to settlement of the associated underlying obligations.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. COMMITMENTS AND CONTINGENCIES The Company is required by its insurance providers to obtain and hold a standby letter of credit. These letters of credit serve as a guarantee by the banking institution to pay the Company’s insurance providers the incurred claim costs attributable to its general liability, workers compensation and automobile liability claims, up to the amount stated in the standby letters of credit, in the event that these claims were not paid by the Company. These letters of credit are cash collateralized, resulting in the cash being designated as restricted. The Company is the subject of certain other claims and lawsuits occurring in the normal course of business. Management, after consultation with legal counsel, does not believe that the outcome of these actions will have a material impact on the Condensed Consolidated Financial Statements of the Company.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	13. INCOME TAXES The Company and its subsidiaries are based in the U.S. and file federal and various state income tax returns. The components of the provision for income taxes were as follows: Three Months Ended March 31, 2020 2019 Current tax expense $ 271 $ 22 Deferred tax expense 913 141 Income tax expense $ 1,184 $ 163 Cash paid for income taxes $ 44 $ — The effective income tax rate varied from the 21% federal statutory rate primarily as a result of the change in tax valuation allowance, state income taxes, and net income attributable to noncontrolling interest owners which is taxable to those owners rather than to the Company and other permanent differences. In addition, 2019 included a reduction in the tax valuation allowance that reduced income tax expense by $203 and 2020 includes state taxes related to Plateau of $332 . Due to the net operating loss carryforwards, the Company expects no cash payments for federal income taxes for 2020 or 2019. The Company makes cash payments for state income taxes in states in which the Company does not have net operating loss carry forwards. At December 31, 2019 the Company had federal and state net operating loss (“NOL”) carryforwards of $83,270 and $44,857 , respectively, which expire at various dates in the next 18 years for U.S. federal income tax and in the next 8 to 18 years for the various state jurisdictions where we operate. Such NOL carryforwards expire beginning in 2028 through 2038. As a result of the Company’s analysis, management has determined that the Company does not have any material uncertain tax positions.

Stock Incentive Plan and Other

Stock Incentive Plan and Other Equity Activity	3 Months Ended
	Mar. 31, 2020
Stockholders' Equity Note [Abstract]
Stock Incentive Plan	14. STOCK INCENTIVE PLAN AND OTHER EQUITY ACTIVITY General —The Company has a stock incentive plan (the “Stock Incentive Plan”) that is administered by the Compensation and Talent Development Committee of the Board of Directors. Under the Stock Incentive Plan, the Company can issue shares to employees and directors in the form of restricted stock awards (“RSAs”), restricted stock units (“RSUs”), and performance based shares (“PSUs”). Changes in common stock, additional paid in capital, and treasury stock during the three months ended March 31, 2020 primarily relate to activity associated with the Stock Incentive Plan and share repurchases. Share Grants —During the three months ended March 31, 2020 , the Company had the following share grants associated with the Stock Incentive Plan: Shares Weighted Average Grant-Date Fair Value per Share RSUs 127 $ 14.08 PSUs 173 $ 14.08 Total shares granted 300 Share Issuances —During the three months ended March 31, 2020 , the Company had the following share issuances associated with the Stock Incentive Plan: Shares RSUs (issued upon vesting) 39 PSUs (issued upon vesting) 86 ESPP (issued upon sale) 13 Total shares issued 138 Stock-Based Compensation Expense —During the three months ended March 31, 2020 and 2019 the Company recognized $2,234 and $1,021 , respectively, of stock-based compensation expense, primarily within general and administrative expenses. The Company recognizes forfeitures as they occur, rather than estimating expected forfeitures. Included within total stock-based compensation expense for the three months ended March 31, 2020 and 2019 is $18 and zero , respectively, of expense related to the Employee Stock Purchase Plan (the “ESPP”). At March 31, 2020 , 774 authorized shares remained available for issuance under the ESPP. Share Withheld for Taxes —The Company withheld 46 shares for taxes on stock-based compensation vestings for $668 during the three months ended March 31, 2020 . Warrants —During the three months ended March 31, 2020 , certain holders of warrants elected the cashless exercise option and the Company issued 110 common shares on the exercise of 470 warrants with a market value of $1,477 . Accumulated Other Comprehensive Income (Loss) (“AOCI”) —The following table presents changes in AOCI, net of tax: Unrealized Fair Value of Swap (Cash Flow Hedge) (1) Balance at December 31, 2019 $ (209 ) Net gain (loss) recognized in OCI, net of tax effect of $2,064 (7,110 ) Amount reclassified from AOCI into earnings, net of tax effect of ($14) 49 Change in OCI, net of tax (7,061 ) Balance at March 31, 2020 $ (7,270 ) (1) See Note 11 - Financial Instruments for further discussion of our cash flow hedges.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share	15. EARNINGS PER SHARE Basic net income per share attributable to Sterling common stockholders is computed by dividing net income attributable to Sterling common stockholders by the weighted average number of common shares outstanding during the period. Diluted net income per common share attributable to Sterling common stockholders is the same as basic net income per share attributable to Sterling common stockholders but includes dilutive unvested stock awards and warrants using the treasury stock method. The following table reconciles the numerators and denominators of the basic and diluted per common share computations for net income attributable to Sterling common stockholders: Three Months Ended March 31, 2020 2019 Numerator: Net income attributable to Sterling common stockholders $ 3,115 $ 1,815 Denominator: Weighted average common shares outstanding — basic 27,736 26,377 Shares for dilutive unvested stock and warrants 256 346 Weighted average common shares outstanding — diluted 27,992 26,723 Basic net income per share attributable to Sterling common stockholders $ 0.11 $ 0.07 Diluted net income per share attributable to Sterling common stockholders $ 0.11 $ 0.07

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segment Information	16. SEGMENT INFORMATION The Company’s internal and public segment reporting are aligned based upon the services offered by its operating groups, which represent the reportable segments. The Company’s operations consist of three reportable segments: Heavy Civil, Specialty Services and Residential. The Company’s Chief Operating Decision Maker evaluates the performance of the operating groups based upon revenue and income from operations. Each operating group’s income from operations reflects corporate costs, allocated based primarily upon revenue. The following table presents total revenue and income from operations by reportable segment for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 2019 Revenue Heavy Civil $ 155,615 $ 150,505 Specialty Services 104,723 30,679 Residential 36,350 42,765 Total Revenue $ 296,688 $ 223,949 Operating Income (Loss) Heavy Civil $ (3,622 ) $ (2,147 ) Specialty Services 11,114 1,048 Residential 5,084 5,819 Subtotal 12,576 4,720 Acquisition related costs (473 ) — Total Operating Income $ 12,103 $ 4,720

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	3 Months Ended
	Mar. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	17. SUPPLEMENTAL CASH FLOW INFORMATION Operating assets and liabilities— The following table summarizes the changes in the components of operating assets and liabilities: Three Months Ended March 31, 2020 2019 Accounts receivable, including retainage $ 26,979 $ (1,976 ) Contracts in progress, net (17,954 ) (9,400 ) Receivables from and equity in construction joint ventures (1,593 ) (905 ) Other current and non-current assets 1,242 2,084 Accounts payable (14,421 ) (17,556 ) Accrued compensation and other liabilities 888 2,602 Members' interest subject to mandatory redemption and undistributed earnings 183 (2,211 ) Changes in operating assets and liabilities $ (4,676 ) $ (27,362 )

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Presentation Basis— The accompanying Condensed Financial Statements are presented in accordance with accounting policies generally accepted in the United States (“GAAP”) and reflect all wholly owned subsidiaries and those entities the Company is required to consolidate. See the “Consolidated 50% Owned Subsidiaries” and “Construction Joint Ventures” section of this Note for further discussion of the Company’s consolidation policy for those entities that are not wholly owned. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, considered necessary for a fair presentation have been included. All significant intercompany accounts and transactions have been eliminated in consolidation. Values presented within tables (excluding per share data) are in thousands. Reclassifications have been made to historical financial data in the Condensed Consolidated Financial Statements to conform to the current year presentation. Estimates and Judgments— The preparation of the accompanying Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Certain accounting estimates of the Company require a higher degree of judgment than others in their application. These include the recognition of revenue and earnings from construction contracts over time, the valuation of long-lived assets, goodwill, income taxes, and purchase accounting estimates, including goodwill and other intangible assets. Management continually evaluates all of its estimates and judgments based on available information and experience; however, actual results could differ from these estimates.
Estimates and Judgments	Estimates and Judgments— The preparation of the accompanying Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Certain accounting estimates of the Company require a higher degree of judgment than others in their application. These include the recognition of revenue and earnings from construction contracts over time, the valuation of long-lived assets, goodwill, income taxes, and purchase accounting estimates, including goodwill and other intangible assets. Management continually evaluates all of its estimates and judgments based on available information and experience; however, actual results could differ from these estimates.
Revenue Recognition	Contracts in Progress— The timing of revenue recognition, billings and costs incurred results in billed accounts receivable and costs and estimated earnings in excess of billings on uncompleted contracts (contract assets) on the Condensed Consolidated Balance Sheet. For performance obligations satisfied over time, amounts are billed as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals (e.g., biweekly or monthly) or upon achievement of contractual milestones. Typically, Sterling bills for advances or deposits from its customers, before revenue is recognized, resulting in billings in excess of costs and estimated earnings on uncompleted contracts (contract liabilities). However, the Company occasionally bills subsequent to revenue recognition, resulting in contract assets. These assets and liabilities are reported on the Condensed Consolidated Balance Sheet on a contract-by-contract basis at the end of each reporting period. Revenue Recognition— Our revenue is derived from long-term contracts for customers in our heavy civil and specialty services business segments, as well as short-term projects for customers in our residential business segment. Accounting treatment for these contracts in accordance with Accounting Standards Update (“ASU”) 2014-09 (Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers ) , is as follows: • Performance Obligations Satisfied Over Time (Heavy Civil and Specialty Services) Recognition of Performance Obligations— A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account in the new revenue standard. The contract transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. Heavy civil projects typically span between 12 to 36 months , and specialty services projects are between 6 to 24 months . The majority of our contracts have a single performance obligation as the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts and, therefore, not distinct. Some contracts have multiple performance obligations, most commonly due to the contract covering multiple phases of the project life cycle (design and construction). Revenues are recognized as our obligations are satisfied over time, using the ratio of project costs incurred to estimated total costs for each contract because of the continuous transfer of control to the customer as all of the work is performed at the customer’s site and, therefore, the customer controls the asset as it is being constructed. This continuous transfer of control to the customer is further supported by clauses in the contract that allow the customer to unilaterally terminate the contract for convenience, pay the Company for costs incurred plus a reasonable profit and take control of any work in process. 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. Items excluded from cost-to-cost— Pre-contract costs are generally not material and are charged to expense as incurred, but in certain cases pre-contract recognition may be deferred if specific probability criteria are met. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Remaining Performance Obligations (“RPOs”)— RPOs represent the amount of revenues we expect to recognize in the future from our contract commitments on projects and are hereafter referred to as “Backlog”. Backlog includes the entire expected revenue values for joint ventures we consolidate and our proportionate value for those we proportionately consolidate. Backlog may not be indicative of future operating results, and projects included in Backlog may be canceled, modified or otherwise altered by customers. See Note 4 - Revenue from Customers , for further discussion. Variable Consideration— Contract modifications through change orders, claims and incentives are routine in the performance of the Company’s contracts to account for changes in the contract specifications or requirements. In most instances, contract modifications are not distinct from the existing contract due to the significant integration of services provided in the contract and are accounted for as a modification of the existing contract and performance obligation. Either the Company or its customers may initiate change orders, which may include changes in specifications or designs, manner of performance, facilities, equipment, materials, sites and period of completion of the work. 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 the Company seeks to collect from its 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. The Company estimates variable consideration for a performance obligation at the most likely amount to which the Company expects to be entitled (or the most likely amount the Company expects to incur in the case of liquidated damages), utilizing estimation methods that best predict the amount of consideration to which the Company will be entitled (or will be incurred in the case of liquidated damages). The Company includes variable consideration in the estimated transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur or when the uncertainty associated with the variable consideration is resolved. The Company’s estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of its anticipated performance and all information (historical, current and forecasted) that is reasonably available to the Company. The effect of variable consideration on the transaction price of a performance obligation is recognized as an adjustment to revenue on a cumulative catch-up basis. To the extent unapproved change orders and claims reflected in the transaction price (or excluded from the transaction price in the case of liquidated damages) are not resolved in the Company’s favor, or to the extent incentives reflected in the transaction price are not earned, there could be reductions in, or reversals of, previously recognized revenue. • Performance Obligations Satisfied at a Point-in-Time (Residential) Revenue for our residential contracts is recognized at a point in time and utilizes an output measure for performance based on the completion of a unit of work (e.g. completion of concrete foundation). The time from starting construction to completion is typically two weeks or less. Upon fulfillment of the performance obligation, the customer is provided an invoice (or equivalent) demonstrating transfer of control to the customer.
Receivables, including Retainage	Receivables, including Retainage— Receivables are generally based on amounts billed to the customer in accordance with contractual provisions. Many of the contracts under which the Company performs work also contain retainage provisions. Retainage refers to that portion of our billings 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. At March 31, 2020 and December 31, 2019 , receivables included $73,400 and $79,400 of retainage. 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 March 31, 2020 and December 31, 2019 , our allowance for doubtful accounts against contracts receivable was zero . 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.
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 20 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. See Note 7 - Property and Equipment for disclosure of the components of property and equipment.
Lease Arrangements	Lease Arrangements— In the ordinary course of business, the Company enters into a variety of lease arrangements, including operating and finance leases. • Operating & Finance Leases— The Company determines if an arrangement is a lease at inception. The operating lease right-of-use (“ROU”) assets are included within the Company’s non-current assets and lease liabilities are included in current or non-current liabilities on the Company’s Condensed Consolidated Balance Sheets. Finance leases are included in “Property and equipment”, “Current maturities of long-term debt”, and “Long-term debt” on the Company’s Condensed Consolidated Balance Sheets. ROU assets represent the Company’s right to use, or control the use of, a specified asset for the lease term. Lease liabilities are the Company’s obligation to make lease payments arising from a lease, and are measured on a discounted basis. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term on the commencement date. As most of the Company’s leases do not provide an implicit rate, the Company’s incremental borrowing rate was used based on the information available on the commencement date in determining the present value of lease payments. For future leases, the implied rate in the lease will be used to determine the present value. The operating lease ROU asset includes any lease payments made and initial direct costs incurred and excludes lease incentives. 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 continues to be recognized on a straight-line basis over the lease term.
Goodwill	Goodwill— Goodwill represents the excess of the cost of companies acquired over the fair value of their net assets at the dates of acquisition. Goodwill is not amortized, but instead is reviewed for impairment at least annually at a reporting unit level, absent any interim indicators of impairment. Interim testing for impairment is performed if indicators of potential impairment exist. We perform our annual impairment assessment during the fourth quarter of each year. We identify a potential impairment by comparing the fair value of the applicable reporting unit to its net book value, including goodwill. To determine the fair value of our reporting units and test for impairment, we utilize an income approach (discounted cash flow method) as we believe this is the most direct approach to incorporate the specific economic attributes and risk profiles of our reporting units into our valuation model. We generally do not utilize a market approach, given the lack of relevant information generated by market transactions involving comparable businesses. However, to the extent market indicators of fair value become available, we consider such market indicators in our discounted cash flow analysis and determination of fair value.
Evaluating Impairment of Other Intangible Assets and Other Long-Lived Assets	Evaluating Impairment of Other Intangible Assets and Other Long-Lived Assets— Our finite-lived intangible assets are amortized over their estimated remaining useful economic lives. Our project-related intangible assets are amortized as the applicable projects progress, customer relationships are amortized utilizing an accelerated method based on the pattern of cash flows expected to be realized, taking into consideration expected revenues and customer attrition, and our other intangibles are amortized utilizing a straight-line method. When events or changes in circumstances indicate that finite-lived intangible and other long-lived assets may be impaired, an evaluation is performed. If the asset or asset group fails the recoverability test, we will perform a fair value measurement to determine and record an impairment charge.
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 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.
Recently Adopted Accounting Guidance	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13 to add the guidance in ASC 326 on the impairment of financial instruments. The ASU introduces an impairment model (known as the current expected credit loss (CECL) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The ASU is also intended to reduce the complexity of U.S. GAAP by decreasing the number of credit impairment models that entities use to account for debt instruments. The amendments in the ASU are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2020 as required and noted no material impact to the Company’s Condensed Consolidated Financial Statements.

Plateau Acquisition (Tables)

Plateau Acquisition (Tables)	3 Months Ended
	Mar. 31, 2020
Business Combinations [Abstract]
Summary of Fair Value Consideration Transferred	Sterling completed the Plateau Acquisition for a purchase price of $427,659 , net of cash acquired, detailed as follows: Cash consideration transferred, net of $2,425 of cash acquired $ 375,000 Target working capital adjustment 21,323 Equity consideration transferred (1,245 shares at $13.01 per share (1) ) 16,195 Note payable to seller (See Note 9 - Debt) 10,000 Estimated tax basis election 5,141 Total consideration $ 427,659 (1) Sterling’s closing stock price on October 1, 2019
Summary of Preliminary Purchase Price Allocation	The following table summarizes our purchase price allocation at the acquisition closing date, net of cash acquired: Net tangible assets: Accounts receivable, including retainage $ 81,921 Costs and estimated earnings in excess of billings 974 Other current assets 249 Property and equipment, net 65,492 Other non-current assets, net 10 Accounts payable (22,039 ) Billings in excess of costs and estimated earnings (16,540 ) Other current liabilities (7,669 ) Total net tangible assets 102,398 Identifiable intangible assets 218,600 Goodwill 106,661 Total consideration transferred $ 427,659
Schedule of Identifiable Intangible Assets Acquired	Weighted Average Life (Years) October 2, 2019 Fair Value Customer relationships 25 $ 191,800 Trade name 25 24,800 Non-compete agreements 5 2,000 Total $ 218,600
Summary of Proforma Information	Three Months Ended March 31, 2019 Pro forma revenue $ 282,609 Pro forma net income attributable to Sterling $ 7,331

Revenue From Contracts With C_2

Revenue From Contracts With Customers (Tables)	3 Months Ended
	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Schedule of Backlog By Segment	The Company had the following backlog, by segment: March 31, December 31, Heavy Civil Backlog $ 886,575 $ 834,049 Specialty Services Backlog 303,545 233,976 Total Heavy Civil and Specialty Services Backlog $ 1,190,120 $ 1,068,025
Disaggregation of Revenue	The following tables present the Company’s revenue disaggregated by major end market and contract type: Three Months Ended March 31, Revenue by major end market 2020 2019 Heavy Highway $ 96,374 $ 93,610 Aviation 28,457 29,937 Water Containment and Treatment 21,809 15,234 Other 8,975 11,724 Heavy Civil Revenue $ 155,615 $ 150,505 Land Development $ 76,245 $ — Commercial 28,478 30,679 Specialty Services Revenue $ 104,723 $ 30,679 Residential Revenue $ 36,350 $ 42,765 Revenues $ 296,688 $ 223,949 Revenue by contract type Fixed-Unit Price $ 141,739 $ 141,219 Lump Sum 114,252 39,132 Residential and Other 40,697 43,598 Revenues $ 296,688 $ 223,949

Consolidated 50% Owned Subsid_2

Consolidated 50% Owned Subsidiaries (Tables)	3 Months Ended
	Mar. 31, 2020
Noncontrolling Interest [Abstract]
Schedule of Components of Agreement Obligation	The liability consists of the following: March 31, December 31, Members’ interest subject to mandatory redemption $ 40,000 $ 40,000 Net accumulated earnings 9,186 9,003 Total liability $ 49,186 $ 49,003
Summary of Financial Information	Summary financial information for Myers is as follows: Three Months Ended March 31, 2020 2019 Revenues $ 44,362 $ 42,414 Operating income $ 155 $ 277 Net income $ 158 $ 282 Summary financial information for SEMA is as follows: Three Months Ended March 31, 2020 2019 Revenues $ 4,064 $ 602 Operating income $ 296 $ 38 Net income $ 299 $ 38 Three Months Ended March 31, 2020 2019 Revenues $ 26,846 $ 31,384 Income before tax $ 2,157 $ 1,969 Sterling’s noncontrolling interest: Revenues $ 13,082 $ 15,684 Income before tax $ 1,049 $ 984

Construction Joint Ventures (Ta

Construction Joint Ventures (Tables)	3 Months Ended
	Mar. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Change in Non-controlling Interest	The following table summarizes the changes in the noncontrolling owners’ interests in subsidiaries and consolidated joint ventures: Three Months Ended March 31, 2020 2019 Balance, beginning of period $ 1,293 $ 7,859 Net income attributable to noncontrolling interest 100 46 Distributions to noncontrolling interest owners — (5,100 ) Balance, end of period $ 1,393 $ 2,805
Condensed Balance Sheet	Condensed combined financial amounts of joint ventures in which the Company has a noncontrolling interest and the Company’s share of such amounts which are included in the Company’s Condensed Consolidated Financial Statements are shown below: March 31, December 31, Current assets $ 60,517 $ 92,710 Current liabilities $ (77,164 ) $ (86,705 ) Sterling’s receivables from and equity in construction joint ventures $ 10,789 $ 9,196
Condensed Income Statement	Summary financial information for Myers is as follows: Three Months Ended March 31, 2020 2019 Revenues $ 44,362 $ 42,414 Operating income $ 155 $ 277 Net income $ 158 $ 282 Summary financial information for SEMA is as follows: Three Months Ended March 31, 2020 2019 Revenues $ 4,064 $ 602 Operating income $ 296 $ 38 Net income $ 299 $ 38 Three Months Ended March 31, 2020 2019 Revenues $ 26,846 $ 31,384 Income before tax $ 2,157 $ 1,969 Sterling’s noncontrolling interest: Revenues $ 13,082 $ 15,684 Income before tax $ 1,049 $ 984

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2020
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment are summarized as follows: March 31, December 31, Construction and transportation equipment $ 221,336 $ 217,945 Buildings and improvements 15,711 14,641 Land 3,891 3,891 Office equipment 2,607 2,767 Total property and equipment 243,545 239,244 Less accumulated depreciation (125,727 ) (123,214 ) Total property and equipment, net $ 117,818 $ 116,030

Other Intangible Assets (Tables

Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	The following table presents the Company’s acquired finite-lived intangible assets at March 31, 2020 and December 31, 2019 : March 31, 2020 December 31, 2019 Weighted Gross Gross Customer relationships 25 years $ 232,623 $ (9,251 ) $ 232,623 $ (6,911 ) Trade name 23 years 30,107 (2,071 ) 30,107 (1,692 ) Non-competition agreements 5 years 2,487 (409 ) 2,487 (291 ) Total 24 years $ 265,217 $ (11,731 ) $ 265,217 $ (8,894 )

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The Company’s outstanding debt was as follows: March 31, December 31, Term Loan Facility $ 395,000 $ 400,000 Revolving Credit Facility 50,000 20,000 Credit Facility 445,000 420,000 Note payable to seller, Plateau Acquisition 10,000 10,000 Notes and deferred payments to sellers, Tealstone Acquisition 12,500 12,230 Notes payable for transportation and construction equipment and other 723 805 Total debt 468,223 443,035 Less - Current maturities of long-term debt (50,211 ) (42,473 ) Less - Unamortized debt issuance costs (9,184 ) (9,935 ) Total long-term debt $ 408,828 $ 390,627

Lease Obligations (Tables)

Lease Obligations (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Schedule of Lease Expenses	The components of lease expense were as follows: Three Months Ended March 31, 2020 2019 Operating lease cost $ 2,159 $ 2,211 Short-term lease cost $ 3,281 $ 4,743 Finance lease cost: Amortization of right-of-use assets $ 56 $ 32 Interest on lease liabilities 8 2 Total finance lease cost $ 64 $ 34 Supplemental cash flow information related to leases was as follows: Three Months Ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,105 $ 2,383 Operating cash flows from finance leases $ 8 $ 2 Financing cash flows from finance leases $ 56 $ 32 Right-of-use assets obtained in exchange for lease obligations (noncash): Operating leases $ 3,540 $ 3,101 Finance leases $ — $ 76 Supplemental balance sheet information related to leases was as follows: March 31, December 31, Operating Leases Operating lease right-of-use assets $ 14,790 $ 13,979 Current portion of long-term lease obligations $ 7,410 $ 7,095 Long-term lease obligations 7,465 6,976 Total operating lease liabilities $ 14,875 $ 14,071 Finance Leases Property and equipment, at cost $ 1,479 $ 1,479 Accumulated depreciation (537 ) (482 ) Property and equipment, net $ 942 $ 997 Current maturities of long-term debt $ 198 $ 204 Long-term debt 509 560 Total finance lease liabilities $ 707 $ 764 Weighted Average Remaining Lease Term Operating leases 2.6 2.5 Finance leases 3.9 4.0 Weighted Average Discount Rate Operating leases 6.0 % 6.0 % Finance leases 4.2 % 4.2 %
Maturities of Lease Liabilities, Operating Leases	Maturities of lease liabilities are as follows: Operating Leases Finance Leases Year Ending December 31, 2020 (excluding the three months ended March 31, 2020) $ 5,159 $ 168 2021 5,720 208 2022 3,768 161 2023 1,624 154 2024 198 77 Thereafter 11 — Total lease payments $ 16,480 $ 768 Less imputed interest (1,605 ) (61 ) Total $ 14,875 $ 707
Maturities of Lease Liabilities, Finance Leases	Maturities of lease liabilities are as follows: Operating Leases Finance Leases Year Ending December 31, 2020 (excluding the three months ended March 31, 2020) $ 5,159 $ 168 2021 5,720 208 2022 3,768 161 2023 1,624 154 2024 198 77 Thereafter 11 — Total lease payments $ 16,480 $ 768 Less imputed interest (1,605 ) (61 ) Total $ 14,875 $ 707

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Liabilities at Fair Value	The following table presents the fair value of the interest rate derivative by valuation hierarchy and balance sheet classification: March 31, 2020 December 31, 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Derivative Assets Other current assets $ — $ — $ — $ — $ — $ 216 $ — $ 216 Other non-current assets — — — — — — — — Total assets at fair value $ — $ — $ — $ — $ — $ 216 $ — $ 216 Derivative Liabilities Other current liabilities $ — $ (4,086 ) $ — $ (4,086 ) $ — $ (61 ) $ — $ (61 ) Other non-current liabilities — (5,438 ) — (5,438 ) — (398 ) — (398 ) Total liabilities at fair value $ — $ (9,524 ) $ — $ (9,524 ) $ — $ (459 ) $ — $ (459 )
Schedule of Derivative Assets at Fair Value	The following table presents the fair value of the interest rate derivative by valuation hierarchy and balance sheet classification: March 31, 2020 December 31, 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Derivative Assets Other current assets $ — $ — $ — $ — $ — $ 216 $ — $ 216 Other non-current assets — — — — — — — — Total assets at fair value $ — $ — $ — $ — $ — $ 216 $ — $ 216 Derivative Liabilities Other current liabilities $ — $ (4,086 ) $ — $ (4,086 ) $ — $ (61 ) $ — $ (61 ) Other non-current liabilities — (5,438 ) — (5,438 ) — (398 ) — (398 ) Total liabilities at fair value $ — $ (9,524 ) $ — $ (9,524 ) $ — $ (459 ) $ — $ (459 )
Schedule of Changes in AOCI	The following table presents the change in other comprehensive income (“OCI”) during the three months ended March 31, 2020 for derivatives designated as cash flow hedges: Before Tax Amount Tax Amount Net of Tax Amount Net gain (loss) recognized in OCI $ (9,174 ) $ 2,064 $ (7,110 ) Net amount reclassified from AOCI into earnings (1) 63 (14 ) 49 Change in OCI $ (9,111 ) $ 2,050 $ (7,061 ) (1) Net unrealized losses totaling $3,946 are anticipated to be reclassified from AOCI into interest expense during the next 12 months due to settlement of the associated underlying obligations. The following table presents changes in AOCI, net of tax: Unrealized Fair Value of Swap (Cash Flow Hedge) (1) Balance at December 31, 2019 $ (209 ) Net gain (loss) recognized in OCI, net of tax effect of $2,064 (7,110 ) Amount reclassified from AOCI into earnings, net of tax effect of ($14) 49 Change in OCI, net of tax (7,061 ) Balance at March 31, 2020 $ (7,270 ) (1) See Note 11 - Financial Instruments for further discussion of our cash flow hedges.

Income Taxes Income Taxes (Tabl

Income Taxes Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Components of Income Taxes	The components of the provision for income taxes were as follows: Three Months Ended March 31, 2020 2019 Current tax expense $ 271 $ 22 Deferred tax expense 913 141 Income tax expense $ 1,184 $ 163 Cash paid for income taxes $ 44 $ —

Stock Incentive Plan and Othe_2

Stock Incentive Plan and Other Equity Activity (Tables)	3 Months Ended
	Mar. 31, 2020
Stockholders' Equity Note [Abstract]
Schedule of Share Grants and Issuances	During the three months ended March 31, 2020 , the Company had the following share grants associated with the Stock Incentive Plan: Shares Weighted Average Grant-Date Fair Value per Share RSUs 127 $ 14.08 PSUs 173 $ 14.08 Total shares granted 300 During the three months ended March 31, 2020 , the Company had the following share issuances associated with the Stock Incentive Plan: Shares RSUs (issued upon vesting) 39 PSUs (issued upon vesting) 86 ESPP (issued upon sale) 13 Total shares issued 138
Schedule of Changes in AOCI	The following table presents the change in other comprehensive income (“OCI”) during the three months ended March 31, 2020 for derivatives designated as cash flow hedges: Before Tax Amount Tax Amount Net of Tax Amount Net gain (loss) recognized in OCI $ (9,174 ) $ 2,064 $ (7,110 ) Net amount reclassified from AOCI into earnings (1) 63 (14 ) 49 Change in OCI $ (9,111 ) $ 2,050 $ (7,061 ) (1) Net unrealized losses totaling $3,946 are anticipated to be reclassified from AOCI into interest expense during the next 12 months due to settlement of the associated underlying obligations. The following table presents changes in AOCI, net of tax: Unrealized Fair Value of Swap (Cash Flow Hedge) (1) Balance at December 31, 2019 $ (209 ) Net gain (loss) recognized in OCI, net of tax effect of $2,064 (7,110 ) Amount reclassified from AOCI into earnings, net of tax effect of ($14) 49 Change in OCI, net of tax (7,061 ) Balance at March 31, 2020 $ (7,270 ) (1) See Note 11 - Financial Instruments for further discussion of our cash flow hedges.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table reconciles the numerators and denominators of the basic and diluted per common share computations for net income attributable to Sterling common stockholders: Three Months Ended March 31, 2020 2019 Numerator: Net income attributable to Sterling common stockholders $ 3,115 $ 1,815 Denominator: Weighted average common shares outstanding — basic 27,736 26,377 Shares for dilutive unvested stock and warrants 256 346 Weighted average common shares outstanding — diluted 27,992 26,723 Basic net income per share attributable to Sterling common stockholders $ 0.11 $ 0.07 Diluted net income per share attributable to Sterling common stockholders $ 0.11 $ 0.07

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following table presents total revenue and income from operations by reportable segment for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 2019 Revenue Heavy Civil $ 155,615 $ 150,505 Specialty Services 104,723 30,679 Residential 36,350 42,765 Total Revenue $ 296,688 $ 223,949 Operating Income (Loss) Heavy Civil $ (3,622 ) $ (2,147 ) Specialty Services 11,114 1,048 Residential 5,084 5,819 Subtotal 12,576 4,720 Acquisition related costs (473 ) — Total Operating Income $ 12,103 $ 4,720

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	The following table summarizes the changes in the components of operating assets and liabilities: Three Months Ended March 31, 2020 2019 Accounts receivable, including retainage $ 26,979 $ (1,976 ) Contracts in progress, net (17,954 ) (9,400 ) Receivables from and equity in construction joint ventures (1,593 ) (905 ) Other current and non-current assets 1,242 2,084 Accounts payable (14,421 ) (17,556 ) Accrued compensation and other liabilities 888 2,602 Members' interest subject to mandatory redemption and undistributed earnings 183 (2,211 ) Changes in operating assets and liabilities $ (4,676 ) $ (27,362 )

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Contract receivables	$ 73,400,000	$ 79,400,000
Allowance for doubtful accounts against contracts receivable	$ 0	0
Ownership interest in subsidiaries	50.00%
Other current assets
Property, Plant and Equipment [Line Items]
Restricted cash, current	$ 4,700,000	$ 4,800,000
Heavy Civil | Minimum
Property, Plant and Equipment [Line Items]
Percentage of completion range	12 months
Heavy Civil | Maximum
Property, Plant and Equipment [Line Items]
Percentage of completion range	36 months
Specialty Services | Minimum
Property, Plant and Equipment [Line Items]
Percentage of completion range	6 months
Specialty Services | Maximum
Property, Plant and Equipment [Line Items]
Percentage of completion range	24 months
Building and Building Improvements | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	5 years
Building and Building Improvements | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	39 years
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	5 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	20 years

Plateau Acquisition - Narrative

Plateau Acquisition - Narrative (Details) - USD ($) $ in Thousands	Oct. 02, 2019	Mar. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill		$ 191,892	$ 191,892
Plateau Excavation
Business Acquisition [Line Items]
Total consideration	$ 427,659
Goodwill	$ 106,661

Plateau Acquisition - Considera

Plateau Acquisition - Consideration Transferred and Purchase Price Allocation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Oct. 02, 2019	Mar. 31, 2020	Dec. 31, 2019	Oct. 01, 2019
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Goodwill		$ 191,892	$ 191,892
Plateau Excavation
Business Acquisition [Line Items]
Cash consideration transferred, net of $2,425 of cash acquired	$ 375,000
Target working capital adjustment	21,323
Share consideration given for acquisitions	16,195
Note payable to seller	10,000
Estimated tax basis election	5,141
Total consideration	427,659
Cash acquired	$ 2,425
Equity consideration transferred (in shares)	1,245
Business acquisition, price per share				$ 13.01
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Accounts receivable, including retainage	$ 81,921
Costs and estimated earnings in excess of billings	974
Other current assets	249
Property and equipment, net	65,492
Other non-current assets, net	10
Accounts payable	22,039
Billings in excess of costs and estimated earnings	16,540
Other current liabilities	7,669
Total net tangible assets	102,398
Identifiable intangible assets	218,600
Goodwill	106,661
Total consideration transferred	$ 427,659

Plateau Acquisition - Schedule

Plateau Acquisition - Schedule of Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Oct. 02, 2019	Mar. 31, 2020
Business Acquisition [Line Items]
Weighted Average Life		24 years
Plateau Excavation
Business Acquisition [Line Items]
Fair Value	$ 218,600
Customer relationships
Business Acquisition [Line Items]
Weighted Average Life		25 years
Customer relationships | Plateau Excavation
Business Acquisition [Line Items]
Weighted Average Life	25 years
Fair Value	$ 191,800
Trade name
Business Acquisition [Line Items]
Weighted Average Life		23 years
Trade name | Plateau Excavation
Business Acquisition [Line Items]
Weighted Average Life	25 years
Fair Value	$ 24,800
Non-competition agreements
Business Acquisition [Line Items]
Weighted Average Life		5 years
Non-competition agreements | Plateau Excavation
Business Acquisition [Line Items]
Weighted Average Life	5 years
Fair Value	$ 2,000

Plateau Acquisition - Supplemen

Plateau Acquisition - Supplemental Pro Forma Information (Details) - Plateau Excavation $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Business Acquisition [Line Items]
Pro forma revenue	$ 282,609
Pro forma net income attributable to Sterling	$ 7,331

Revenue From Contracts With C_3

Revenue From Contracts With Customers - Backlog By Segment (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Backlog	$ 1,190,120	$ 1,068,025
Heavy Civil
Disaggregation of Revenue [Line Items]
Backlog	886,575	834,049
Specialty Services
Disaggregation of Revenue [Line Items]
Backlog	$ 303,545	$ 233,976

Revenue From Contracts With C_4

Revenue From Contracts With Customers - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Remaining performance obligation expected to be recognized over next twelve months	65.00%
Costs and Estimated Earnings in Excess of Billings
Disaggregation of Revenue [Line Items]
Contracts receivable unpaid project contract price	$ 7,100		$ 3,000
Operating income (Loss)
Disaggregation of Revenue [Line Items]
Estimated construction gain (loss) before tax	$ 95	$ (200)

Revenue From Contracts With C_5

Revenue From Contracts With Customers - Additional Information (Details)	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Remaining performance obligation expected to be recognized over next twelve months	65.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period	12 months

Revenue From Contracts With C_6

Revenue From Contracts With Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 296,688	$ 223,949
Fixed-Unit Price
Disaggregation of Revenue [Line Items]
Revenues	141,739	141,219
Lump Sum
Disaggregation of Revenue [Line Items]
Revenues	114,252	39,132
Residential and Other
Disaggregation of Revenue [Line Items]
Revenues	40,697	43,598
Heavy Civil
Disaggregation of Revenue [Line Items]
Revenues	155,615	150,505
Heavy Civil | Heavy Highway
Disaggregation of Revenue [Line Items]
Revenues	96,374	93,610
Heavy Civil | Aviation
Disaggregation of Revenue [Line Items]
Revenues	28,457	29,937
Heavy Civil | Water Containment and Treatment
Disaggregation of Revenue [Line Items]
Revenues	21,809	15,234
Heavy Civil | Other
Disaggregation of Revenue [Line Items]
Revenues	8,975	11,724
Specialty Services
Disaggregation of Revenue [Line Items]
Revenues	104,723	30,679
Specialty Services | Land Development
Disaggregation of Revenue [Line Items]
Revenues	76,245	0
Specialty Services | Commercial
Disaggregation of Revenue [Line Items]
Revenues	28,478	30,679
Specialty Services
Disaggregation of Revenue [Line Items]
Revenues	$ 36,350	$ 42,765

Consolidated 50% Owned Subsid_3

Consolidated 50% Owned Subsidiaries - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)entity	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)
Noncontrolling Interest [Line Items]
Ownership interest in subsidiaries	50.00%
Number of entities | entity	2
Total disability insurance policies, per policy amount	$ 20,000
Members’ interest subject to mandatory redemption	40,000		$ 40,000
Myers
Noncontrolling Interest [Line Items]
Net accumulated earnings	1,700	$ 1,300
Variable Interest Entity, Primary Beneficiary | Myers
Noncontrolling Interest [Line Items]
Members’ interest subject to mandatory redemption	$ 20,000

Consolidated 50% Owned Subsid_4

Consolidated 50% Owned Subsidiaries - Components of Noncontrolling Interest (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Noncontrolling Interest [Abstract]
Members’ interest subject to mandatory redemption	$ 40,000	$ 40,000
Net accumulated earnings	9,186	9,003
Total liability	$ 49,186	$ 49,003

Consolidated 50% Owned Subsid_5

Consolidated 50% Owned Subsidiaries Consolidated 50% Owned Subsidiaries - Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Variable Interest Entity [Line Items]
Operating income	$ 12,103	$ 4,720
Net income	3,115	1,815
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Revenues	44,362	42,414
Operating income	155	277
Net income	$ 158	$ 282

Construction Joint Ventures - C

Construction Joint Ventures - Change in Non-controlling Interest (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Balance, beginning of period	$ 1,293	$ 7,859
Net income attributable to noncontrolling interest	100	46
Distributions to noncontrolling interest owners	0	5,100
Balance, end of period	$ 1,393	$ 2,805

Construction Joint Ventures - S

Construction Joint Ventures - SEMA Financials (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Revenues	$ 296,688	$ 223,949
Operating income	12,103	4,720
Net income attributable to Sterling common stockholders	$ 3,115	1,815
RLW | Joint Ventures
Schedule of Equity Method Investments [Line Items]
Ownership percentage	51.00%
SEMA Construction Inc | Joint Ventures
Schedule of Equity Method Investments [Line Items]
Ownership percentage	49.00%
Revenues	$ 4,064	602
Operating income	296	38
Net income attributable to Sterling common stockholders	$ 299	$ 38

Construction Joint Ventures -_2

Construction Joint Ventures - Construction Joint Ventures, Partner Share (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Current assets	$ 371,088	$ 357,521
Current liabilities	286,332	293,504
Sterling’s receivables from and equity in noncontrolling construction joint ventures	10,789	9,196
Joint Ventures
Schedule of Equity Method Investments [Line Items]
Current assets	60,517	92,710
Current liabilities	77,164	86,705
Sterling’s receivables from and equity in noncontrolling construction joint ventures	$ 10,789	$ 9,196

Construction Joint Ventures - I

Construction Joint Ventures - Income Statement Information (Details) - Joint Ventures - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Revenues	$ 26,846	$ 31,384
Income before tax	2,157	1,969
Sterling’s noncontrolling interest:
Revenues	13,082	15,684
Income before tax	$ 1,049	$ 984

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 243,545		$ 239,244
Less accumulated depreciation	(125,727)		(123,214)
Total property and equipment, net	117,818		116,030
Depreciation	5,448	$ 3,702
Construction and transportation equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	221,336		217,945
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	15,711		14,641
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,891		3,891
Office equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,607		$ 2,767

Other Intangible Assets (Detail

Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	24 years
Gross Carrying Amount	$ 265,217		$ 265,217
Accumulated Amortization	(11,731)		(8,894)
Amortization of intangible assets	$ 2,837	$ 600
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	25 years
Gross Carrying Amount	$ 232,623		232,623
Accumulated Amortization	$ (9,251)		(6,911)
Trade name
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	23 years
Gross Carrying Amount	$ 30,107		30,107
Accumulated Amortization	$ (2,071)		(1,692)
Non-competition agreements
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	5 years
Gross Carrying Amount	$ 2,487		2,487
Accumulated Amortization	$ (409)		$ (291)

Debt - Long-term Debt (Details)

Debt - Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt	$ 468,223	$ 443,035
Less - Current maturities of long-term debt	(50,211)	(42,473)
Less - Unamortized debt issuance costs	(9,184)	(9,935)
Total long-term debt	408,828	390,627
Secured Debt | Term Loan Facility
Debt Instrument [Line Items]
Long-term debt	395,000	400,000
Secured Debt | Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt	50,000	20,000
Secured Debt | Credit Facility
Debt Instrument [Line Items]
Long-term debt	445,000	420,000
Notes Payable, Other Payables | Plateau Excavation
Debt Instrument [Line Items]
Long-term debt	10,000	10,000
Notes Payable, Other Payables | Notes payable for transportation and construction equipment and other
Debt Instrument [Line Items]
Long-term debt	723	805
Tealstone Construction | Notes Payable, Other Payables
Debt Instrument [Line Items]
Long-term debt	$ 12,500	$ 12,230

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	Oct. 02, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 05, 2019
Debt Instrument [Line Items]
Amortization of debt issuance costs		$ 752,000	$ 833,000
Long-term debt		468,223,000							$ 443,035,000
Plateau Excavation
Debt Instrument [Line Items]
Liabilities incurred	$ 10,000,000
Tealstone Construction
Debt Instrument [Line Items]
Promissory notes issued to the sellers		5,000,000
Deferred cash payments due		7,500,000
Credit Facility
Debt Instrument [Line Items]
Fees related to establishment of debt		$ 10,688,000
Secured Debt
Debt Instrument [Line Items]
Fixed charge ratio minimum		1.20
Secured Debt | Credit Agreement
Debt Instrument [Line Items]
Debt instrument face amount	475,000,000
Secured Debt | Credit Facility
Debt Instrument [Line Items]
Long-term debt		$ 445,000,000							420,000,000
Secured Debt | Term Loan Facility
Debt Instrument [Line Items]
Weighted average interest rate		6.05%
Long-term debt		$ 395,000,000							400,000,000
Notes Payable, Other Payables | Plateau Excavation
Debt Instrument [Line Items]
Liabilities incurred	$ 10,000,000
Stated interest rate	8.00%
Notes Payable, Other Payables | Tealstone Construction
Debt Instrument [Line Items]
Long-term debt		12,500,000							12,230,000
Notes Payable, Other Payables | Notes payable for transportation and construction equipment and other
Debt Instrument [Line Items]
Long-term debt		$ 723,000							$ 805,000
Notes Payable, Other Payables | Notes payable for transportation and construction equipment and other | Minimum
Debt Instrument [Line Items]
Stated interest rate		2.99%
Debt instrument, term		3 years
Notes Payable, Other Payables | Notes payable for transportation and construction equipment and other | Maximum
Debt Instrument [Line Items]
Stated interest rate		6.92%
Debt instrument, term		5 years
Revolving Credit Facility | Secured Debt | Term Loan Facility
Debt Instrument [Line Items]
Debt instrument face amount	$ 400,000,000
Revolving Credit Facility | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	75,000,000
Debt instrument, base interest rate		4.25%
Debt instrument, LIBOR interest rate		0.93%
Line of credit, remaining borrowing capacity		$ 25,000,000
Weighted average interest rate		6.17%
Revolving Credit Facility | Line of Credit | Revolving Credit Facility | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate		3.50%
Revolving Credit Facility | Line of Credit | Revolving Credit Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		4.50%
Swing Line Loan | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 15,000,000
Interest Rate Swap | Secured Debt
Debt Instrument [Line Items]
Derivative, notional amount		$ 350,000,000								$ 350,000,000
Forecast | Secured Debt | Term Loan Facility
Debt Instrument [Line Items]
Periodic payments				$ 220,000,000	$ 50,000,000	$ 50,000,000	$ 50,000,000	$ 30,000,000
October 1, 2019 - June 30, 2020 | Secured Debt | Credit Agreement
Debt Instrument [Line Items]
Leverage ratio maximum		4
July 1, 2020 - September 30, 2020 | Secured Debt | Credit Agreement
Debt Instrument [Line Items]
Leverage ratio maximum		3.75
October 1, 2020 - March 31, 2021 | Secured Debt | Credit Agreement
Debt Instrument [Line Items]
Leverage ratio maximum		3.50
April 1, 2021 - June 30, 2021 | Secured Debt | Credit Agreement
Debt Instrument [Line Items]
Leverage ratio maximum		3.25
October 1, 2021 - December 31, 2021 | Secured Debt | Credit Agreement
Debt Instrument [Line Items]
Leverage ratio maximum		3

Lease Obligations (Details)

Lease Obligations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Lease termination period	10 years
Lease, Cost [Abstract]
Operating lease cost	$ 2,159	$ 2,211
Short-term lease cost	3,281	4,743
Finance lease cost:
Amortization of right-of-use assets	56	32
Interest on lease liabilities	8	2
Total finance lease cost	64	34
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	2,105	2,383
Operating cash flows from finance leases	8	2
Financing cash flows from finance leases	56	32
Right-of-use assets obtained in exchange for lease obligations (noncash):
Operating leases	3,540	3,101
Finance leases	0	$ 76
Assets and Liabilities, Lessee [Abstract]
Operating lease right-of-use assets ($3,938 and $3,817 related to VIEs)	14,790		$ 13,979
Current portion of long-term lease obligations	7,410		7,095
Long-term lease obligations	7,465		6,976
Total operating lease liabilities	14,875		14,071
Property and equipment, at cost	1,479		1,479
Accumulated depreciation	(537)		(482)
Property and equipment, net	942		997
Current maturities of long-term debt	198		204
Long-term debt	509		560
Total finance lease liabilities	$ 707		$ 764
Weighted average remaining lease term: operating leases	2 years 6 months 26 days		2 years 6 months 7 days
Weighted average remaining lease term: financing leases	3 years 10 months 10 days		4 years 11 days
Weighted average discount rate: operating lease	6.00%		6.00%
Weighted average discount rate: financing lease	4.20%		4.20%
Operating Leases
2020 (excluding the three months ended March 31, 2020)	$ 5,159
2021	5,720
2022	3,768
2023	1,624
2024	198
Thereafter	11
Total lease payments	16,480
Less imputed interest	(1,605)
Total operating lease liabilities	14,875		$ 14,071
Finance Leases
2020 (excluding the three months ended March 31, 2020)	168
2021	208
2022	161
2023	154
2024	77
Thereafter	0
Total lease payments	768
Less imputed interest	(61)
Total finance lease liabilities	$ 707		$ 764
Minimum
Lessee, Lease, Description [Line Items]
Lease renewal term	1 month
Maximum
Lessee, Lease, Description [Line Items]
Lease renewal term	5 years

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Dec. 05, 2019	Oct. 02, 2019
Derivative [Line Items]
Unrealized gain (loss) on derivatives	$ (9,111,000)
Interest Rate Swap
Derivative [Line Items]
Unrealized gain (loss) on derivatives	(9,524,000)
Secured Debt | Interest Rate Swap
Derivative [Line Items]
Derivative, notional amount	$ 350,000,000	$ 350,000,000
Secured Debt | Revolving Credit Facility | Term Loan Facility
Derivative [Line Items]
Debt instrument face amount			$ 400,000,000

Financial Instruments - Fair Va

Financial Instruments - Fair Value of the Interest Rate Derivative (Details) - Fair Value, Recurring - Interest Rate Swap - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Derivative Assets
Other current assets	$ 0	$ 216
Other non-current assets	0	0
Total assets at fair value	0	216
Derivative Liabilities
Other current liabilities	(4,086)	(61)
Other non-current liabilities	(5,438)	(398)
Total liabilities at fair value	(9,524)	(459)
Level 1
Derivative Assets
Other current assets	0	0
Other non-current assets	0	0
Total assets at fair value	0	0
Derivative Liabilities
Other current liabilities	0	0
Other non-current liabilities	0	0
Total liabilities at fair value	0	0
Level 2
Derivative Assets
Other current assets	0	216
Other non-current assets	0	0
Total assets at fair value	0	216
Derivative Liabilities
Other current liabilities	(4,086)	(61)
Other non-current liabilities	(5,438)	(398)
Total liabilities at fair value	(9,524)	(459)
Level 3
Derivative Assets
Other current assets	0	0
Other non-current assets	0	0
Total assets at fair value	0	0
Derivative Liabilities
Other current liabilities	0	0
Other non-current liabilities	0	0
Total liabilities at fair value	$ 0	$ 0

Financial Instruments - Schedul

Financial Instruments - Schedule of Total Value Recognized in Other Comprehensive Income (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net gain (loss) recognized in OCI, before tax amount	$ (9,174)
Net gain (loss) recognized in OCI, tax amount	2,064
Net gain (loss) recognized in OCI, net of tax amount	(7,110)
Net amount reclassified from AOCI into earnings, before tax amount	63
Net amount reclassified from AOCI into earnings, tax amount	(14)
Net amount reclassified from AOCI into earnings, net of tax amount	49
Change in OCI, before tax amount	(9,111)
Change in OCI, tax amount	2,050
Change in OCI, net of tax amount	(7,061)
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Change in OCI, before tax amount	(9,524)
Interest Expense | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Unrealized gains expected to be reclassified from AOCI within next 12 months	$ (3,946)

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Current tax expense	$ 271	$ 22	$ 22
Deferred tax expense	913	141
Income tax expense	1,184	163
Cash paid for income taxes	44	0
Effective income tax reconciliation, decrease in valuation allowance		$ 203
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards			$ 83,270
Operating loss carryforward expiration period			18 years
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards			$ 44,857
Minimum | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforward expiration period			8 years
Maximum | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforward expiration period			18 years
Plateau Excavation
Operating Loss Carryforwards [Line Items]
Effective income tax reconciliation, state income taxes	$ 332

Stock Incentive Plan and Othe_3

Stock Incentive Plan and Other Equity Activity - Share Grants (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Class of Stock [Line Items]
Shares granted (in shares)	300
RSUs
Class of Stock [Line Items]
Shares granted (in shares)	127
Weighted Average Grant-Date Fair Value per Share | $ / shares	$ 14.08
PSUs
Class of Stock [Line Items]
Shares granted (in shares)	173
Weighted Average Grant-Date Fair Value per Share | $ / shares	$ 14.08

Stock Incentive Plan and Othe_4

Stock Incentive Plan and Other Equity Activity - Share Issuances (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2020shares
Class of Stock [Line Items]
Shares issued (in shares)	138
RSUs
Class of Stock [Line Items]
Shares issued (in shares)	39
PSUs
Class of Stock [Line Items]
Shares issued (in shares)	86
ESPP
Class of Stock [Line Items]
Shares issued (in shares)	13

Stock Incentive Plan and Othe_5

Stock Incentive Plan and Other Equity Activity (Details) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)shares	Mar. 31, 2019USD ($)shares
Sale of Stock [Line Items]
Stock-based compensation expense | $	$ 2,234	$ 1,021
Shares withheld for taxes (in shares) | shares	46
Shares withheld for taxes | $	$ (772)	(564)
Shares issued from warrants | shares	110
Number of warrants exercised | shares	470
Fair value of warrants exercised | $	$ 1,477
Employee Stock Purchase Plan | ESPP
Sale of Stock [Line Items]
Stock-based compensation expense | $	$ 18	$ 0
Remaining authorized shares available for purchase (in shares) | shares	774
Treasury Stock
Sale of Stock [Line Items]
Shares withheld for taxes (in shares) | shares	46	45
Shares withheld for taxes | $	$ (668)	$ (564)

Stock Incentive Plan and Othe_6

Stock Incentive Plan and Other Equity Activity - Schedule of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 221,211	$ 172,260
Net gain (loss) recognized in OCI, net of tax amount	(7,110)
Net amount reclassified from AOCI into earnings, net of tax amount	(49)
Change in OCI, net of tax amount	(7,061)	0
Ending balance	218,930	$ 166,277
Net gain (loss) recognized in OCI, tax amount	2,064
Net amount reclassified from AOCI into earnings, tax amount	14
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(209)
Net gain (loss) recognized in OCI, net of tax amount	(7,110)
Net amount reclassified from AOCI into earnings, net of tax amount	49
Change in OCI, net of tax amount	(7,061)
Ending balance	$ (7,270)

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Net income attributable to Sterling common stockholders	$ 3,115	$ 1,815
Denominator:
Weighted average common shares outstanding - basic (in shares)	27,736	26,377
Shares for dilutive unvested stock and warrants (in shares)	256	346
Weighted average common shares outstanding - diluted (in shares)	27,992	26,723
Basic net income per share attributable to Sterling common stockholders (in dollars per share)	$ 0.11	$ 0.07
Diluted net income per share attributable to Sterling common stockholders (in dollars per share)	$ 0.11	$ 0.07

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)segment	Mar. 31, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3
Revenues	$ 296,688	$ 223,949
Operating Income (Loss)	12,103	4,720
Acquisition related costs	(473)	0
Heavy Civil
Segment Reporting Information [Line Items]
Revenues	155,615	150,505
Operating Income (Loss)	(3,622)	(2,147)
Specialty Services
Segment Reporting Information [Line Items]
Revenues	104,723	30,679
Operating Income (Loss)	11,114	1,048
Specialty Services
Segment Reporting Information [Line Items]
Revenues	36,350	42,765
Operating Income (Loss)	5,084	5,819
Operating Segments
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ 12,576	$ 4,720

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Supplemental Cash Flow Elements [Abstract]
Accounts receivable, including retainage	$ 26,979	$ (1,976)
Contracts in progress, net	(17,954)	(9,400)
Receivables from and equity in construction joint ventures	(1,593)	(905)
Other current and non-current assets	1,242	2,084
Accounts payable	(14,421)	(17,556)
Accrued compensation and other liabilities	888	2,602
Members' interest subject to mandatory redemption and undistributed earnings	183	(2,211)
Changes in operating assets and liabilities	$ (4,676)	$ (27,362)