Sterling Infrastructure (STRL) 10-Q 6 Aug 19 2019 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Aug. 02, 2019
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		26,466,675
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Current Reporting Status	Yes
Amendment Flag	false
Entity 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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenues	$ 264,086	$ 268,734	$ 488,035	$ 491,226
Cost of revenues	(238,590)	(237,688)	(443,036)	(440,346)
Gross profit	25,496	31,046	44,999	50,880
General and administrative expense	(10,774)	(13,203)	(23,263)	(25,543)
Other operating expense, net	(3,538)	(5,694)	(5,832)	(6,509)
Operating income	11,184	12,149	15,904	18,828
Interest income	291	201	655	330
Interest expense	(2,904)	(3,112)	(5,964)	(6,199)
Income before income taxes	8,571	9,238	10,595	12,959
Income tax expense	(706)	(97)	(869)	(138)
Net income	7,865	9,141	9,726	12,821
Less: Net income attributable to noncontrolling interests	(37)	(967)	(83)	(2,158)
Net income attributable to Sterling common stockholders	$ 7,828	$ 8,174	$ 9,643	$ 10,663
Net income per share attributable to Sterling common stockholders:
Basic (in dollars per share)	$ 0.30	$ 0.30	$ 0.37	$ 0.40
Diluted (in dollars per share)	$ 0.29	$ 0.30	$ 0.36	$ 0.39
Weighted average common shares outstanding:
Basic (in shares)	26,338	26,887	26,357	26,881
Diluted (in shares)	26,623	27,125	26,657	27,162

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 71,730	$ 94,095
Accounts receivable, including retainage	157,813	145,026
Costs and estimated earnings in excess of billings on uncompleted contracts	53,896	41,542
Inventory	3,252	3,159
Receivables from and equity in construction joint ventures	14,381	10,720
Other current assets	7,951	8,074
Total current assets	309,023	302,616
Property and equipment, net	49,217	51,999
Operating lease right-of-use assets	14,995
Goodwill	85,231	85,231
Other intangibles, net	41,218	42,418
Other non-current assets, net	211	309
Total assets	499,895	482,573
Current liabilities:
Accounts payable	101,342	99,426
Billings in excess of costs and estimated earnings	60,571	62,407
Current maturities of long-term debt	12,128	2,899
Current portion of long-term lease obligations	7,059
Income taxes payable	101	318
Accrued compensation	12,148	9,448
Other current liabilities	5,183	4,676
Total current liabilities	198,532	179,174
Long-term debt	66,497	79,117
Long-term lease obligations	8,030
Members’ interest subject to mandatory redemption and undistributed earnings	48,831	49,343
Deferred taxes	2,211	1,450
Other long-term liabilities	1,101	1,229
Total liabilities	325,202	310,313
Commitments and contingencies
Stockholders’ equity:
Preferred stock, par value $0.01 per share; 1,000 shares authorized, none issued	0	0
Common stock, par value $0.01 per share; 38,000 shares authorized, 27,049 and 27,064 shares issued, 26,466 and 26,597 shares outstanding	271	271
Additional paid in capital	233,559	233,795
Treasury Stock, at cost: 583 and 467 shares	(6,688)	(4,731)
Retained deficit	(55,291)	(64,934)
Total Sterling stockholders’ equity	171,851	164,401
Noncontrolling interests	2,842	7,859
Total stockholders’ equity	174,693	172,260
Total liabilities and stockholders’ equity	$ 499,895	$ 482,573

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
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)	27,049,000	27,064,000
Common stock, shares outstanding (in shares)	26,466,000	26,597,000
Treasury stock (in shares)	583,000	467,000

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income	$ 9,726	$ 12,821
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	8,473	8,307
Amortization of deferred debt costs	1,602	1,610
Gain on disposal of property and equipment	(441)	(470)
Deferred tax expense	761	0
Stock-based compensation expense	1,670	1,383
Changes in operating assets and liabilities (Note 15)	(26,116)	(31,565)
Net cash used in operating activities	(4,325)	(7,914)
Cash flows from investing activities:
Capital expenditures	(4,854)	(5,263)
Proceeds from sale of property and equipment	802	1,307
Net cash used in investing activities	(4,052)	(3,956)
Cash flows from financing activities:
Repayments of long-term debt	(5,763)	(5,344)
Distributions to noncontrolling interest owners	(5,100)	0
Purchase of treasury stock	(3,201)	0
Other	76	(154)
Net cash used in financing activities	(13,988)	(5,498)
Net decrease in cash and cash equivalents	(22,365)	(17,368)
Cash and cash equivalents at beginning of period	94,095	83,953
Cash and cash equivalents at end of period	$ 71,730	$ 66,585

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid in Capital	Retained Deficit	Treasury Stock	Total Sterling Stockholders’ Equity	Noncontrolling Interests
Beginning balance at Dec. 31, 2017	$ 146,189	$ 271	$ 231,183	$ (90,121)	$ 0	$ 141,333	$ 4,856
Beginning balance (in shares) at Dec. 31, 2017		27,051			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,680			2,489		2,489	1,191
Stock-based compensation	617		617			617
Stock-based compensation (in shares)		3
Shares withheld for taxes	(194)	$ (1)	(193)			(194)
Shares withheld for taxes (in shares)		(13)
Ending balance at Mar. 31, 2018	150,292	$ 270	231,607	(87,632)	$ 0	144,245	6,047
Ending balance (in shares) at Mar. 31, 2018		27,035			0
Beginning balance at Dec. 31, 2017	146,189	$ 271	231,183	(90,121)	$ 0	141,333	4,856
Beginning balance (in shares) at Dec. 31, 2017		27,051			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,821
Ending balance at Jun. 30, 2018	160,092	$ 271	232,265	(79,458)	$ 0	153,078	7,014
Ending balance (in shares) at Jun. 30, 2018		27,064			0
Beginning balance at Mar. 31, 2018	150,292	$ 270	231,607	(87,632)	$ 0	144,245	6,047
Beginning balance (in shares) at Mar. 31, 2018		27,035			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,141			8,174		8,174	967
Stock-based compensation	766		766			766
Stock-based compensation (in shares)		39
Shares withheld for taxes	(107)	$ 1	(108)			(107)
Shares withheld for taxes (in shares)		(10)
Ending balance at Jun. 30, 2018	160,092	$ 271	232,265	(79,458)	$ 0	153,078	7,014
Ending balance (in shares) at Jun. 30, 2018		27,064			0
Beginning balance at Dec. 31, 2018	172,260	$ 271	233,795	(64,934)	$ (4,731)	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
Stock-based compensation	1,021		1,021			1,021
Stock-based compensation (in shares)		(1)
Distributions to owners	(5,100)						(5,100)
Purchase of treasury stock	(3,201)				$ (3,201)	(3,201)
Purchase of treasury stock (in shares)		250			250
Issuance of stock	0		(1,314)		$ 1,314
Issuance of stock (in shares)		130			(130)
Shares withheld for taxes	(564)				$ (564)	(564)
Shares withheld for taxes (in shares)		(52)			(45)
Ending balance at Mar. 31, 2019	166,277	$ 271	233,502	(63,119)	$ (7,182)	163,472	2,805
Ending balance (in shares) at Mar. 31, 2019		26,424			632
Beginning balance at Dec. 31, 2018	172,260	$ 271	233,795	(64,934)	$ (4,731)	164,401	7,859
Beginning balance (in shares) at Dec. 31, 2018		26,597			467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,726
Ending balance at Jun. 30, 2019	174,693	$ 271	233,559	(55,291)	$ (6,688)	171,851	2,842
Ending balance (in shares) at Jun. 30, 2019		26,466			583
Beginning balance at Mar. 31, 2019	166,277	$ 271	233,502	(63,119)	$ (7,182)	163,472	2,805
Beginning balance (in shares) at Mar. 31, 2019		26,424			632
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	7,865			7,828		7,828	37
Stock-based compensation	649		649			649
Distributions to owners	0
Purchase of treasury stock	0
Issuance of stock	0		(494)		$ 494
Issuance of stock (in shares)		49			(49)
Shares withheld for taxes	(98)		(98)			(98)
Shares withheld for taxes (in shares)		(7)
Ending balance at Jun. 30, 2019	$ 174,693	$ 271	$ 233,559	$ (55,291)	$ (6,688)	$ 171,851	$ 2,842
Ending balance (in shares) at Jun. 30, 2019		26,466			583

Nature of Operations

Nature of Operations	6 Months Ended
	Jun. 30, 2019
Nature of Operations [Abstract]
Nature of Operations	1. NATURE OF OPERATIONS Nature of Operations —Sterling Construction Company, Inc. (“Sterling” or “the Company”), a Delaware corporation, is a construction company that specializes in heavy civil infrastructure construction and infrastructure rehabilitation as well as residential construction projects. We operate primarily in Arizona, California, Colorado, Hawaii, Nevada, Texas and Utah, as well as other states in which there are feasible construction opportunities. Heavy civil construction projects include highways, roads, bridges, airfields, ports, light rail, water, wastewater and storm drainage systems, foundations for multi-family homes, commercial concrete projects and parking structures. Residential construction projects include concrete foundations for single-family homes.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	2. BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation— The Condensed Consolidated Financial Statements included herein have been prepared by the Company, without audit, in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been either condensed or omitted pursuant to SEC rules and regulations. The Condensed Consolidated Financial Statements reflect, in the opinion of management, all normal recurring adjustments necessary to present fairly the Company’s financial position at June 30, 2019 and the results of operations and cash flows for the periods presented. The December 31, 2018 Condensed Consolidated Balance Sheet data herein was derived from audited financial statements, but as discussed above, does not include all disclosures required by GAAP. Interim results may be subject to significant seasonal variations and the results of operations for the quarters presented are not necessarily indicative of the results expected for the full year or subsequent quarters. Values presented within tables, excluding per share data, are in thousands. Principles of Consolidation— The accompanying Condensed Consolidated Financial Statements 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 footnote 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. Consolidated 50% Owned Subsidiaries— The accompanying Condensed Consolidated Financial Statements include the accounts of two subsidiaries in which the Company has 50% ownership interest and exercises control over such entities. Therefore, the Company has consolidated these two entities. Both subsidiaries have individual provisions which, under circumstances that are certain to occur, obligate the Company to purchase each partner’s 50% interests. The Company has classified these obligations as mandatorily redeemable and has recorded a liability in “Members’ interest subject to mandatory redemption and undistributed earnings” on the Condensed Consolidated Balance Sheets. Each partner’s portion of net income (loss) is reflected in the Condensed Consolidated Statements of Operations line item “Other operating expense, net”. 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. Use of Estimates— The preparation of the accompanying Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions 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 of the Company’s accounting policies require higher degrees of judgment than others in their application. These include the recognition of revenue from construction contracts over time and the valuation of goodwill, other intangibles and income taxes. Management continually evaluates all of its estimates and judgments based on available information and experience; however, actual results could differ from these estimates. Reclassification— Reclassifications have been made to historical financial data on the Company’s Condensed Consolidated Financial Statements to conform to the Company’s current year presentation. Heavy Civil Construction Revenue Recognition— The Company engages in various types of heavy civil construction projects principally for public (government) owners. Revenues are recognized as performance obligations are satisfied over time (formerly known as percentage-of-completion method), using the ratio of costs incurred to estimated total costs for each contract. This cost to cost measure is used because management considers it to be the best available measure of progress on these contracts. Contract costs include all direct material, labor, subcontract and other costs and those indirect costs determined to relate to contract performance, such as indirect salaries and wages, equipment repairs and depreciation, insurance and payroll taxes. Administrative and general expenses are charged to expense as incurred. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Changes in job performance, job conditions, estimated profitability and associated change orders and claims, including those changes arising from contract penalty provisions and final contract settlements, may result in revisions to costs and income and are recognized in the period in which the revisions are determined. Change orders, claims and incentives are generally not distinct from the existing contract due to the significant integration service provided in the context of the contract and are accounted for as a modification of the existing contract and performance obligation. Change orders may include changes in specifications or designs, manner of performance, facilities, equipment, materials, sites and period of completion of the work. Either the Company or its customers may initiate change orders. Change orders that are unapproved as to both price and scope are evaluated as claims. 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 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 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 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 transaction price (or excluded from transaction price in the case of liquidated damages) are not resolved in the Company’s favor, or to the extent incentives reflected in transaction price are not earned, there could be reductions in, or reversals of, previously recognized revenue. 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. Contract modifications are routine in the performance of the Company’s contracts. Contracts are often modified to account for changes in the contract specifications or requirements. In most instances, contract modifications are for goods or services that are not distinct, and, therefore, are accounted for as part of the existing contract. Assurance-type warranties are the only warranties provided by the Company and, as such, the Company does not recognize revenue on warranty-related work. The Company generally provides a one to two year warranty for workmanship under its contracts when completed. Warranty claims historically have been insignificant. Pre-contract costs are generally charged to expense as incurred, but in certain cases their recognition may be deferred if specific probability criteria are met. The Company had no significant deferred pre-contract costs at June 30, 2019 . Residential Construction Revenue Recognition— Residential construction revenue and related profit are recognized when construction on the concrete foundation unit is completed (i.e., at a point in time). The time from starting construction to finishing is typically less than one month. Leases— Effective January 1, 2019, 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 other 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. Restricted cash— Restricted cash of approximately $3,200 and $3,900 is included in “ Other current assets ” on the Condensed Consolidated Balance Sheets at June 30, 2019 and December 31, 2018 . This 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. Recently Adopted Accounting Guidance Leases— In February 2016, the Financial Accounting Standards Board (“FASB”) issued its new lease accounting guidance in ASU 2016-2, “Leases” (ASC 842). Under the new guidance, lessees are required to recognize all leases (with the exception of short-term leases) on the balance sheet. The Company adopted ASC 842 effective January 1, 2019 using the modified retrospective method. The new guidance has been applied to leases that exist or were entered into on or after January 1, 2019 without adjusting comparative periods in the financial statements. As an accounting policy, the Company has elected not to apply the recognition requirements to short-term leases (leases with terms of 12 months or less). Instead, the Company recognizes the lease payments in the Condensed Consolidated Statement of Operations on a straight-line basis over the lease term and variable lease payments in the period in which the obligation for those payments is incurred. The Company has elected to utilize the package of practical expedients that allows entities to not reassess 1) the classification of leases existing at the date of adoption 2) the initial direct costs for any existing leases and 3) whether any expired or existing contracts are or contain leases. At January 1, 2019, the Company recorded an ROU asset, current maturity of operating lease liability and long-term operating lease liability of $13,600 , $6,200 and $7,400 , respectively on its Condensed Consolidated Balance Sheet, related to its existing operating leases. The adoption of this standard did not have a material impact on the Company’s Condensed Consolidated Statements of Operations. As of June 30, 2019 , the weighted average remaining lease terms for the Company’s various operating leases extends out over the next 2.8 years . The weighted average discount rate used to determine the present value of the Company’s operating leases’ future payments was approximately 6.0% .

Revenue From Contracts With Cus

Revenue From Contracts With Customers	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue From Contracts With Customers	3. REVENUE FROM CONTRACTS WITH CUSTOMERS Performance Obligations Satisfied Over Time —Revenue for the heavy civil construction segment contracts that satisfy the criteria for over time recognition is recognized as the work progresses. The majority of the revenue is derived from long-term, heavy civil construction contracts and projects that typically span between 12 months to 36 months . Revenue from products and services transferred to customers over time accounted for 86% and 84% of revenue for the three and six months ended June 30, 2019 , respectively. Revenue from products and services transferred to customers over time accounted for 83% and 84% of revenue for the three and six months ended June 30, 2018 , respectively. Performance Obligations Satisfied at a Point in Time —Revenue for the residential construction segment contracts that do not satisfy the criteria for over time recognition 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., residential foundation). The typical time frame for completion of a residential foundation is less than one month. Revenue from products and services transferred to customers at a point in time accounted for 14% and 16% of revenue for the three and six months ended June 30, 2019 , respectively. Revenue from products and services transferred to customers at a point in time accounted for 17% and 16% of revenue for the three and six months ended June 30, 2018 , respectively. Backlog —On June 30, 2019 , the Company had approximately $909,000 of remaining performance obligations (which is also referred to as “backlog”) in its heavy civil construction segment. The Company expects to recognize approximately 70% of its backlog as revenue during the next twelve months, and the balance thereafter. Contract Estimates —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 approximately $3,500 and $3,300 for the three and six months ended June 30, 2019 , respectively, and a net increase of approximately $300 and $1,700 for the three and six months ended June 30, 2018 , respectively, included in “Operating income” on the Condensed Consolidated Statements of Operations. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Variable Consideration —The transaction price for contracts may include variable consideration, which includes increases to transaction price for approved and unapproved change orders, claims and incentives, and reductions to transaction price for liquidated damages. 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, the Company concluded that it was appropriate to include amounts of approximately $15,700 and $9,300 at June 30, 2019 and December 31, 2018 , respectively, in project price. These amounts, reflected in “Costs and estimated earnings in excess of billings on uncompleted contracts” on the Condensed Consolidated Balance Sheets, primarily relate to extended delays on a bridge project in Texas due to design errors in the original owner provided project plan. However, unapproved change order and claim amounts are subject to negotiations which may cause actual results to differ materially from estimated and recorded amounts. Revenue by Heavy Civil Construction Category —The Company’s heavy civil construction segment’s portfolio of products and services consists of approximately 150 active contracts. The following series of tables presents the Company’s heavy civil construction revenue disaggregated by several categories: Revenue by major end market Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Heavy Highway $ 129,964 $ 126,554 $ 223,574 $ 233,962 Commercial 28,575 29,109 59,425 57,628 Aviation 37,061 27,832 66,998 51,084 Water Containment and Treatment 15,515 15,521 30,749 30,516 Other 17,015 24,267 28,568 37,334 Total Heavy Civil Construction Revenue $ 228,130 $ 223,283 $ 409,314 $ 410,524 Revenue by contract type Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Fixed Unit Price $ 185,297 $ 194,485 $ 326,516 $ 354,721 Lump Sum and Other 42,833 28,798 82,798 55,803 Total Heavy Civil Construction Revenue $ 228,130 $ 223,283 $ 409,314 $ 410,524 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 when 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. Contract Balances —The timing of revenue recognition, billings and cash collections 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. In the Company’s heavy civil construction segment, 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. Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. However, the Company occasionally receives 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). 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. Changes in the contract asset and liability balances during the six month period ended June 30, 2019 , were not materially impacted by any other factors.

Consolidated 50% Owned Subsidia

Consolidated 50% Owned Subsidiaries	6 Months Ended
	Jun. 30, 2019
Noncontrolling Interest [Abstract]
Consolidated 50% Owned Subsidiaries	4. CONSOLIDATED 50% OWNED SUBSIDIARIES The Company has a 50% interest in two subsidiaries (Myers and RHB); both subsidiaries have individual provisions which obligate the Company to purchase each partner’s 50% interests for $20,000 ( $40,000 in the aggregate), due to circumstances outlined in the partner agreements that are certain to occur. Therefore, the Company has consolidated these two entities and classified these obligations as mandatorily redeemable and has recorded a liability in “ Members’ interest subject to mandatory redemption and undistributed earnings ” on the Condensed Consolidated Balance Sheets. In addition, all undistributed earnings at the time of the noncontrolling owners’ death or permanent disability are also mandatorily payable. In the event of either Mr. Buenting’s or Mr. Myers’s death, the Company 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. The liability consists of the following: June 30, December 31, Members’ interest subject to mandatory redemption $ 40,000 $ 40,000 Net accumulated earnings 8,831 9,343 Total liability $ 48,831 $ 49,343 Fifty percent of the earnings of these consolidated 50% owned subsidiaries for the three and six months ended June 30, 2019 were approximately $1,500 and $2,700 , respectively and for the three and six months ended June 30, 2018 were $4,700 and $5,300 , respectively. These amounts were included in “Other operating expense, net” on the Company’s Condensed Consolidated Statements of Operations. 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 Sterling 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. The following tables present the condensed financial information of Myers, which is reflected in the Company’s Condensed Consolidated Balance Sheets and Statements of Operations: June 30, December 31, Assets Current assets: Cash and cash equivalents $ 6,195 $ 8,745 Accounts receivable, including retainage 27,011 24,109 Other current assets 14,959 14,533 Total current assets 48,165 47,387 Property and equipment, net 6,369 7,219 Operating lease right-of-use assets 3,232 — Goodwill 1,501 1,501 Total assets $ 59,267 $ 56,107 Liabilities Current liabilities: Accounts payable $ 23,672 $ 22,211 Other current liabilities 10,583 9,811 Total current liabilities 34,255 32,022 Other long-term liabilities 1,680 1,976 Total liabilities $ 35,935 $ 33,998

Construction Joint Ventures

Construction Joint Ventures	6 Months Ended
	Jun. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Construction Joint Ventures	5. 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. Joint ventures with a noncontrolling interest —Where the Company is a noncontrolling venture partner, the Company accounts for their 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 (“ 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: June 30, December 31, Total combined: Current assets $ 95,991 $ 64,815 Less current liabilities (98,192 ) (74,543 ) Net liabilities $ (2,201 ) $ (9,728 ) Sterling’s receivables from and equity in noncontrolling construction joint ventures $ 14,381 $ 10,720 Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Total combined: Revenues $ 55,306 $ 25,463 $ 86,690 $ 56,820 Income before tax 8,844 2,192 10,813 5,596 Sterling’s noncontrolling interest: Revenues $ 25,971 $ 12,564 $ 41,655 $ 27,629 Income before tax 3,116 1,167 4,100 2,858 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 complete and the warranty period, if any, has passed.

Property and Equipment

Property and Equipment	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment	6. PROPERTY AND EQUIPMENT Property and equipment are summarized as follows: June 30, December 31, Construction and transportation equipment $ 147,796 $ 144,630 Buildings and improvements 11,195 11,072 Land 2,720 2,720 Office equipment 2,627 2,711 Total property and equipment 164,338 161,133 Less accumulated depreciation (115,121 ) (109,134 ) Total property and equipment, net $ 49,217 $ 51,999

Other Intangible Assets

Other Intangible Assets	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Other Intangible Assets	7. OTHER INTANGIBLE ASSETS The following table presents the Company’s acquired finite-lived intangible assets at June 30, 2019 and December 31, 2018 : June 30, 2019 December 31, 2018 Weighted Gross Gross Customer relationships 23 years $ 40,823 $ (4,062 ) $ 40,823 $ (3,159 ) Trade name 13 years 5,307 (1,181 ) 5,307 (919 ) Non-competition agreements 7 years 487 (156 ) 487 (121 ) Total 22 years $ 46,617 $ (5,399 ) $ 46,617 $ (4,199 ) The Company's intangible amortization expense was $600 and $1,200 for the three and six months ended June 30, 2019 .

Debt

Debt	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt	8. DEBT The Company’s outstanding debt at June 30, 2019 and December 31, 2018 was as follows: June 30, December 31, Oaktree Facility $ 71,602 $ 74,571 Notes and deferred payments to sellers (Tealstone Acquisition) 11,710 13,572 Notes payable for construction and transportation equipment 1,015 612 Total debt 84,327 88,755 Less - Current maturities of long-term debt (12,128 ) (2,899 ) Less - Unamortized deferred debt costs (5,702 ) (6,739 ) Total long-term debt, net of unamortized debt costs $ 66,497 $ 79,117 Oaktree Facility —At June 30, 2019 , the Company had $71,602 outstanding under an $85,000 term loan with Wilmington Trust, National Association, as agent, and the lenders party thereto (the “Oaktree Facility”). The five-year Oaktree Facility, which matures in April, 2022, is secured by substantially all of the assets of the Company and its subsidiaries. Interest on the Oaktree Facility is equal to the one-, two-, three- or six-month London Interbank Offered Rate, or LIBOR, plus 8.75% per annum on the unpaid principal amount of the Oaktree Facility, subject to adjustment under certain circumstances, and is generally payable monthly. There are no amortized principal payments; however, the Company is required to prepay the Oaktree Facility, and in certain cases pay a prepayment premium thereon, with proceeds received from the issuances of debt or equity, transfers, events of loss and extraordinary receipts. The Company is required to make an offer quarterly to the lenders to prepay the Oaktree Facility in an amount equal to 75% of its excess cash flow, plus accrued and unpaid interest thereon and a prepayment premium. Notes and Deferred Payments to Sellers —At June 30, 2019 , the Company had $11,710 outstanding, net of debt discounts, of the combined Promissory Notes and deferred cash payments issued as part of the Tealstone Acquisition. During the six months ended June 30, 2019 , the Company paid approximately $2,400 of the 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. Based on a 12% discount rate, the Company recorded $11,600 as notes and deferred payments to sellers in long-term debt on its Condensed Consolidated Balance Sheet at the acquisition closing date. Accreted interest for the period was approximately $300 and $600 for the three and six months ended June 30, 2019 and $300 and $600 for the three and six months ended June 30, 2018 , and was recorded as interest expense. Notes Payable for Construction and Transportation Equipment —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 approximately $1,015 and $600 at June 30, 2019 and December 31, 2018 , respectively. The notes have payment terms ranging from 3 to 5 years and the associated interest rates range from 2.99% to 6.92% . Compliance —The Oaktree Facility contains various covenants that limit, among other things, the Company’s ability and certain of its subsidiaries’ ability to incur certain indebtedness, grant certain liens, merge or consolidate, sell assets, make certain loans, enter into acquisitions, incur capital expenditures, make investments, and pay dividends. In addition, the Company is required to maintain the following principal financial covenants: • a ratio of secured indebtedness to EBITDA of not more than 1.9 to 1.00 for the trailing four consecutive fiscal quarters ending March 31, 2019, reducing to 1.8 to 1.00 for the four consecutive quarters ending September 30, 2019 through maturity in 2022; • daily cash collateral of not less than $15,000 ; • gross margin in contract backlog of not less than $70,000 for the average of the trailing four consecutive fiscal quarters; • net capital expenditures during the trailing four consecutive fiscal quarters shall not exceed $15,000 ; • bonding capacity shall be maintained at all times in an amount not less than $1,000,000 ; and • the EBITDA of Tealstone Residential Concrete, Inc. shall not be less than $12,000 for each of the trailing four consecutive fiscal quarters. The Company is in compliance with these covenants at June 30, 2019 .

Lease Obligations

Lease Obligations	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lease Obligations	9. 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 June 30, 2019 Six Months Ended June 30, 2019 Operating lease cost $ 1,960 $ 4,171 Short-term lease cost $ 3,269 $ 8,012 Finance lease cost: Amortization of right-of-use assets $ 39 $ 71 Interest on lease liabilities 1 3 Total finance lease cost $ 40 $ 74 Supplemental cash flow information related to leases was as follows: Six Months Ended June 30, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 4,466 Operating cash flows from finance leases $ 3 Financing cash flows from finance leases $ 71 Right-of-use assets obtained in exchange for lease obligations (noncash): Operating leases $ 6,311 Finance leases $ 770 Supplemental balance sheet information related to leases was as follows: June 30, 2019 Operating Leases Operating lease right-of-use assets $ 14,995 Current portion of long-term lease obligations $ 7,059 Long-term lease obligations 8,030 Total operating lease liabilities $ 15,089 Finance Leases Property and equipment, at cost $ 1,433 Accumulated depreciation (347 ) Property and equipment, net $ 1,086 Current maturities of long-term debt $ 234 Long-term debt 626 Total finance lease liabilities $ 860 Weighted Average Remaining Lease Term Operating leases 2.8 Finance leases 4.4 Weighted Average Discount Rate Operating leases 6.0 % Finance leases 4.2 % Maturities of lease liabilities are as follows: Operating Leases Finance Leases Year Ending December 31, 2019 (excluding the six months ended June 30, 2019) $ 4,206 $ 157 2020 5,885 209 2021 4,231 186 2022 2,087 161 2023 399 154 Thereafter 5 77 Total lease payments $ 16,813 $ 944 Less imputed interest (1,724 ) (84 ) Total $ 15,089 $ 860
Lease Obligations	9. 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 June 30, 2019 Six Months Ended June 30, 2019 Operating lease cost $ 1,960 $ 4,171 Short-term lease cost $ 3,269 $ 8,012 Finance lease cost: Amortization of right-of-use assets $ 39 $ 71 Interest on lease liabilities 1 3 Total finance lease cost $ 40 $ 74 Supplemental cash flow information related to leases was as follows: Six Months Ended June 30, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 4,466 Operating cash flows from finance leases $ 3 Financing cash flows from finance leases $ 71 Right-of-use assets obtained in exchange for lease obligations (noncash): Operating leases $ 6,311 Finance leases $ 770 Supplemental balance sheet information related to leases was as follows: June 30, 2019 Operating Leases Operating lease right-of-use assets $ 14,995 Current portion of long-term lease obligations $ 7,059 Long-term lease obligations 8,030 Total operating lease liabilities $ 15,089 Finance Leases Property and equipment, at cost $ 1,433 Accumulated depreciation (347 ) Property and equipment, net $ 1,086 Current maturities of long-term debt $ 234 Long-term debt 626 Total finance lease liabilities $ 860 Weighted Average Remaining Lease Term Operating leases 2.8 Finance leases 4.4 Weighted Average Discount Rate Operating leases 6.0 % Finance leases 4.2 % Maturities of lease liabilities are as follows: Operating Leases Finance Leases Year Ending December 31, 2019 (excluding the six months ended June 30, 2019) $ 4,206 $ 157 2020 5,885 209 2021 4,231 186 2022 2,087 161 2023 399 154 Thereafter 5 77 Total lease payments $ 16,813 $ 944 Less imputed interest (1,724 ) (84 ) Total $ 15,089 $ 860

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. COMMITMENT 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. The Company has cash collateralized the letters of credit, 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	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	11. INCOME TAXES The Company and its subsidiaries file U.S. federal and various U.S. state income tax returns. Current income tax expense (benefit) represents federal and state taxes based on tax paid or expected to be payable or receivable for the periods shown in the Condensed Consolidated Statements of Operations. Due to net operating loss carryforwards, the Company does not expect a current federal liability. The Company may incur current state tax liabilities in states in which the Company does not have net operating loss carry forwards. Current income tax expense of $86 and $108 was recorded for the three and six months ended June 30, 2019 , respectively and for the three and six months ended June 30, 2018 was $97 and $138 , respectively. The Company’s deferred tax expense reflects the change in deferred tax assets and liabilities. The Company performs an analysis at the end of each reporting period to determine whether it is more likely than not the deferred tax assets are expected to be realized in future years. Based upon this analysis, a valuation allowance of approximately $31,700 has been applied to the Company’s net deferred tax assets at both June 30, 2019 and December 31, 2018 . As part of this analysis, the Company monitors its quarterly results. Based on the Company’s continued positive income trend and current forecast for the full year of 2019, we believe that there could be enough positive evidence to remove the valuation allowance in the fourth quarter of 2019. Deferred tax liabilities are a consideration in the analysis of whether to apply a valuation allowance because taxable temporary differences may be used as a source of taxable income to support the realization of deferred tax assets. A deferred tax liability that relates to an asset with an indefinite life, such as goodwill, may not be considered a source of income and should not be netted against deferred tax assets for valuation allowance purposes. The Company expects to have a deferred tax liability for the excess of book over tax basis difference in its goodwill. A $620 and $761 deferred tax expense for the three and six months ended June 30, 2019 , respectively has been recorded to reflect this liability. The effective income tax rate varied from the statutory rate primarily as a result of the change in the valuation allowance, net income attributable to noncontrolling interest owners which is taxable to those owners rather than to the Company, state income taxes and other permanent differences. For interim periods, the Company estimates an annual effective tax rate and applies that rate to year-to-date operating results. 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	6 Months Ended
	Jun. 30, 2019
Stockholders' Equity Note [Abstract]
Stock Incentive Plan and Other Equity Activity	12. 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 six months ended June 30, 2019 primarily relate to activity associated with the Stock Incentive Plan and share repurchases. Share Grants —During the six months ended June 30, 2019 , the Company had the following share grants associated with the Stock Incentive Plan: Shares Weighted Average Grant-Date Fair Value per Share RSAs 52 $ 12.06 RSUs 138 $ 10.96 PSUs 185 $ 10.89 Total shares granted 375 — Share Issuances —During the six months ended June 30, 2019 , the Company had the following share issuances associated with the Stock Incentive Plan: Shares RSA (issued upon grant) 52 RSUs (issued upon vesting) 73 PSUs (issued upon vesting) 54 Total shares issued 179 Stock-Based Compensation Expense —During the three and six months ended June 30, 2019 the Company recognized $649 and $1,670 , respectively, of stock-based compensation expense, and during the three and six months ended June 30, 2018 the Company recognized $766 and $1,383 of stock-based compensation expense, primarily within general and administrative expenses. The Company recognizes forfeitures as they occur, rather than estimating expected forfeitures. Share Repurchases —During the six months ended June 30, 2019 , the Company repurchased 250 shares of the Company’s outstanding common stock for $3,201 under the stock repurchase plan, all of which were purchased in the first quarter of 2019. The Company also repurchased 7 and 59 shares for taxes withheld on stock-based compensation vestings for $98 and $662 during the three and six months ended June 30, 2019 .

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	13. EARNINGS PER SHARE 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: Net income attributable to Sterling common stockholders $ 7,828 $ 8,174 $ 9,643 $ 10,663 Denominator: Weighted average common shares outstanding — basic 26,338 26,887 26,357 26,881 Shares for dilutive unvested stock and warrants 285 238 300 281 Weighted average common shares outstanding — diluted 26,623 27,125 26,657 27,162 Basic net income per share attributable to Sterling common stockholders $ 0.30 $ 0.30 $ 0.37 $ 0.40 Diluted net income per share attributable to Sterling common stockholders $ 0.29 $ 0.30 $ 0.36 $ 0.39

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segment Information	14. SEGMENT INFORMATION Segment reporting is aligned based upon the services offered by two operating groups, which represent the following reportable segments: heavy civil construction and residential construction. The Company’s Chief Operating Decision Maker (“CODM”) evaluates the performance of the aforementioned operating groups based upon revenue and income from operations. Each operating group’s income from operations reflects corporate costs, allocated based primarily upon revenue. The following table presents total revenue and income from operations by reportable segment for the three and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Revenues Heavy Civil Construction $ 228,130 $ 223,283 $ 409,314 $ 410,524 Residential Construction 35,956 45,451 78,721 80,702 Total Revenues $ 264,086 $ 268,734 $ 488,035 $ 491,226 Operating Income Heavy Civil Construction $ 6,146 $ 6,395 $ 5,299 $ 8,340 Residential Construction 5,038 5,754 10,605 10,488 Total Operating Income $ 11,184 $ 12,149 $ 15,904 $ 18,828

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	15. SUPPLEMENTAL CASH FLOW INFORMATION Operating assets and liabilities— The following table summarizes the changes in the components of operating assets and liabilities: Six Months Ended June 30, 2019 2018 Accounts receivable, including retainage $ (12,787 ) $ (30,534 ) Contracts in progress, net (14,190 ) (3,346 ) Receivables from and equity in construction joint ventures (3,661 ) (386 ) Other assets 128 1,562 Accounts payable 1,916 (1,073 ) Accrued compensation and other liabilities 2,990 1,761 Member’s interest subject to mandatory redemption and undistributed earnings (512 ) 451 Changes in operating assets and liabilities $ (26,116 ) $ (31,565 )

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation— The Condensed Consolidated Financial Statements included herein have been prepared by the Company, without audit, in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been either condensed or omitted pursuant to SEC rules and regulations. The Condensed Consolidated Financial Statements reflect, in the opinion of management, all normal recurring adjustments necessary to present fairly the Company’s financial position at June 30, 2019 and the results of operations and cash flows for the periods presented. The December 31, 2018 Condensed Consolidated Balance Sheet data herein was derived from audited financial statements, but as discussed above, does not include all disclosures required by GAAP. Interim results may be subject to significant seasonal variations and the results of operations for the quarters presented are not necessarily indicative of the results expected for the full year or subsequent quarters. Values presented within tables, excluding per share data, are in thousands.
Principles of Consolidation	Principles of Consolidation— The accompanying Condensed Consolidated Financial Statements 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 footnote 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. Consolidated 50% Owned Subsidiaries— The accompanying Condensed Consolidated Financial Statements include the accounts of two subsidiaries in which the Company has 50% ownership interest and exercises control over such entities. Therefore, the Company has consolidated these two entities. Both subsidiaries have individual provisions which, under circumstances that are certain to occur, obligate the Company to purchase each partner’s 50% interests. The Company has classified these obligations as mandatorily redeemable and has recorded a liability in “Members’ interest subject to mandatory redemption and undistributed earnings” on the Condensed Consolidated Balance Sheets. Each partner’s portion of net income (loss) is reflected in the Condensed Consolidated Statements of Operations line item “Other operating expense, net”. 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.
Use of Estimates	Use of Estimates— The preparation of the accompanying Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions 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 of the Company’s accounting policies require higher degrees of judgment than others in their application. These include the recognition of revenue from construction contracts over time and the valuation of goodwill, other intangibles and income taxes. Management continually evaluates all of its estimates and judgments based on available information and experience; however, actual results could differ from these estimates.
Reclassification	Reclassification— Reclassifications have been made to historical financial data on the Company’s Condensed Consolidated Financial Statements to conform to the Company’s current year presentation.
Revenue Recognition	Heavy Civil Construction Revenue Recognition— The Company engages in various types of heavy civil construction projects principally for public (government) owners. Revenues are recognized as performance obligations are satisfied over time (formerly known as percentage-of-completion method), using the ratio of costs incurred to estimated total costs for each contract. This cost to cost measure is used because management considers it to be the best available measure of progress on these contracts. Contract costs include all direct material, labor, subcontract and other costs and those indirect costs determined to relate to contract performance, such as indirect salaries and wages, equipment repairs and depreciation, insurance and payroll taxes. Administrative and general expenses are charged to expense as incurred. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Changes in job performance, job conditions, estimated profitability and associated change orders and claims, including those changes arising from contract penalty provisions and final contract settlements, may result in revisions to costs and income and are recognized in the period in which the revisions are determined. Change orders, claims and incentives are generally not distinct from the existing contract due to the significant integration service provided in the context of the contract and are accounted for as a modification of the existing contract and performance obligation. Change orders may include changes in specifications or designs, manner of performance, facilities, equipment, materials, sites and period of completion of the work. Either the Company or its customers may initiate change orders. Change orders that are unapproved as to both price and scope are evaluated as claims. 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 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 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 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 transaction price (or excluded from transaction price in the case of liquidated damages) are not resolved in the Company’s favor, or to the extent incentives reflected in transaction price are not earned, there could be reductions in, or reversals of, previously recognized revenue. 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. Contract modifications are routine in the performance of the Company’s contracts. Contracts are often modified to account for changes in the contract specifications or requirements. In most instances, contract modifications are for goods or services that are not distinct, and, therefore, are accounted for as part of the existing contract. Assurance-type warranties are the only warranties provided by the Company and, as such, the Company does not recognize revenue on warranty-related work. The Company generally provides a one to two year warranty for workmanship under its contracts when completed. Warranty claims historically have been insignificant. Pre-contract costs are generally charged to expense as incurred, but in certain cases their recognition may be deferred if specific probability criteria are met. The Company had no significant deferred pre-contract costs at June 30, 2019 . Residential Construction Revenue Recognition— Residential construction revenue and related profit are recognized when construction on the concrete foundation unit is completed (i.e., at a point in time). The time from starting construction to finishing is typically less than one month.
Leases	Leases— Effective January 1, 2019, 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 other 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.
Restricted Cash	Restricted cash— Restricted cash of approximately $3,200 and $3,900 is included in “ Other current assets ” on the Condensed Consolidated Balance Sheets at June 30, 2019 and December 31, 2018 . This 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.
Recently Adopted Accounting Guidance	Recently Adopted Accounting Guidance Leases— In February 2016, the Financial Accounting Standards Board (“FASB”) issued its new lease accounting guidance in ASU 2016-2, “Leases” (ASC 842). Under the new guidance, lessees are required to recognize all leases (with the exception of short-term leases) on the balance sheet. The Company adopted ASC 842 effective January 1, 2019 using the modified retrospective method. The new guidance has been applied to leases that exist or were entered into on or after January 1, 2019 without adjusting comparative periods in the financial statements. As an accounting policy, the Company has elected not to apply the recognition requirements to short-term leases (leases with terms of 12 months or less). Instead, the Company recognizes the lease payments in the Condensed Consolidated Statement of Operations on a straight-line basis over the lease term and variable lease payments in the period in which the obligation for those payments is incurred. The Company has elected to utilize the package of practical expedients that allows entities to not reassess 1) the classification of leases existing at the date of adoption 2) the initial direct costs for any existing leases and 3) whether any expired or existing contracts are or contain leases. At January 1, 2019, the Company recorded an ROU asset, current maturity of operating lease liability and long-term operating lease liability of $13,600 , $6,200 and $7,400 , respectively on its Condensed Consolidated Balance Sheet, related to its existing operating leases. The adoption of this standard did not have a material impact on the Company’s Condensed Consolidated Statements of Operations. As of June 30, 2019 , the weighted average remaining lease terms for the Company’s various operating leases extends out over the next 2.8 years . The weighted average discount rate used to determine the present value of the Company’s operating leases’ future payments was approximately 6.0% .

Revenue From Contracts With C_2

Revenue From Contracts With Customers (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following series of tables presents the Company’s heavy civil construction revenue disaggregated by several categories: Revenue by major end market Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Heavy Highway $ 129,964 $ 126,554 $ 223,574 $ 233,962 Commercial 28,575 29,109 59,425 57,628 Aviation 37,061 27,832 66,998 51,084 Water Containment and Treatment 15,515 15,521 30,749 30,516 Other 17,015 24,267 28,568 37,334 Total Heavy Civil Construction Revenue $ 228,130 $ 223,283 $ 409,314 $ 410,524 Revenue by contract type Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Fixed Unit Price $ 185,297 $ 194,485 $ 326,516 $ 354,721 Lump Sum and Other 42,833 28,798 82,798 55,803 Total Heavy Civil Construction Revenue $ 228,130 $ 223,283 $ 409,314 $ 410,524

Consolidated 50% Owned Subsid_2

Consolidated 50% Owned Subsidiaries (Tables)	6 Months Ended
	Jun. 30, 2019
Noncontrolling Interest [Abstract]
Schedule of Components of Agreement Obligation	The liability consists of the following: June 30, December 31, Members’ interest subject to mandatory redemption $ 40,000 $ 40,000 Net accumulated earnings 8,831 9,343 Total liability $ 48,831 $ 49,343
Summary of Financial Information of Variable Interest Entities	The following tables present the condensed financial information of Myers, which is reflected in the Company’s Condensed Consolidated Balance Sheets and Statements of Operations: June 30, December 31, Assets Current assets: Cash and cash equivalents $ 6,195 $ 8,745 Accounts receivable, including retainage 27,011 24,109 Other current assets 14,959 14,533 Total current assets 48,165 47,387 Property and equipment, net 6,369 7,219 Operating lease right-of-use assets 3,232 — Goodwill 1,501 1,501 Total assets $ 59,267 $ 56,107 Liabilities Current liabilities: Accounts payable $ 23,672 $ 22,211 Other current liabilities 10,583 9,811 Total current liabilities 34,255 32,022 Other long-term liabilities 1,680 1,976 Total liabilities $ 35,935 $ 33,998

Construction Joint Ventures (Ta

Construction Joint Ventures (Tables)	6 Months Ended
	Jun. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
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: June 30, December 31, Total combined: Current assets $ 95,991 $ 64,815 Less current liabilities (98,192 ) (74,543 ) Net liabilities $ (2,201 ) $ (9,728 ) Sterling’s receivables from and equity in noncontrolling construction joint ventures $ 14,381 $ 10,720
Condensed Income Statement	Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Total combined: Revenues $ 55,306 $ 25,463 $ 86,690 $ 56,820 Income before tax 8,844 2,192 10,813 5,596 Sterling’s noncontrolling interest: Revenues $ 25,971 $ 12,564 $ 41,655 $ 27,629 Income before tax 3,116 1,167 4,100 2,858

Property and Equipment (Tables)

Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment are summarized as follows: June 30, December 31, Construction and transportation equipment $ 147,796 $ 144,630 Buildings and improvements 11,195 11,072 Land 2,720 2,720 Office equipment 2,627 2,711 Total property and equipment 164,338 161,133 Less accumulated depreciation (115,121 ) (109,134 ) Total property and equipment, net $ 49,217 $ 51,999

Other Intangible Assets (Tables

Other Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, 2019 and December 31, 2018 : June 30, 2019 December 31, 2018 Weighted Gross Gross Customer relationships 23 years $ 40,823 $ (4,062 ) $ 40,823 $ (3,159 ) Trade name 13 years 5,307 (1,181 ) 5,307 (919 ) Non-competition agreements 7 years 487 (156 ) 487 (121 ) Total 22 years $ 46,617 $ (5,399 ) $ 46,617 $ (4,199 )

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The Company’s outstanding debt at June 30, 2019 and December 31, 2018 was as follows: June 30, December 31, Oaktree Facility $ 71,602 $ 74,571 Notes and deferred payments to sellers (Tealstone Acquisition) 11,710 13,572 Notes payable for construction and transportation equipment 1,015 612 Total debt 84,327 88,755 Less - Current maturities of long-term debt (12,128 ) (2,899 ) Less - Unamortized deferred debt costs (5,702 ) (6,739 ) Total long-term debt, net of unamortized debt costs $ 66,497 $ 79,117

Lease Obligations (Tables)

Lease Obligations (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Schedule of Lease Expenses	The components of lease expense were as follows: Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Operating lease cost $ 1,960 $ 4,171 Short-term lease cost $ 3,269 $ 8,012 Finance lease cost: Amortization of right-of-use assets $ 39 $ 71 Interest on lease liabilities 1 3 Total finance lease cost $ 40 $ 74 Supplemental cash flow information related to leases was as follows: Six Months Ended June 30, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 4,466 Operating cash flows from finance leases $ 3 Financing cash flows from finance leases $ 71 Right-of-use assets obtained in exchange for lease obligations (noncash): Operating leases $ 6,311 Finance leases $ 770 Supplemental balance sheet information related to leases was as follows: June 30, 2019 Operating Leases Operating lease right-of-use assets $ 14,995 Current portion of long-term lease obligations $ 7,059 Long-term lease obligations 8,030 Total operating lease liabilities $ 15,089 Finance Leases Property and equipment, at cost $ 1,433 Accumulated depreciation (347 ) Property and equipment, net $ 1,086 Current maturities of long-term debt $ 234 Long-term debt 626 Total finance lease liabilities $ 860 Weighted Average Remaining Lease Term Operating leases 2.8 Finance leases 4.4 Weighted Average Discount Rate Operating leases 6.0 % Finance leases 4.2 %
Maturities of Lease Liabilities, Operating Leases	Maturities of lease liabilities are as follows: Operating Leases Finance Leases Year Ending December 31, 2019 (excluding the six months ended June 30, 2019) $ 4,206 $ 157 2020 5,885 209 2021 4,231 186 2022 2,087 161 2023 399 154 Thereafter 5 77 Total lease payments $ 16,813 $ 944 Less imputed interest (1,724 ) (84 ) Total $ 15,089 $ 860
Maturities of Lease Liabilities, Finance Leases	Maturities of lease liabilities are as follows: Operating Leases Finance Leases Year Ending December 31, 2019 (excluding the six months ended June 30, 2019) $ 4,206 $ 157 2020 5,885 209 2021 4,231 186 2022 2,087 161 2023 399 154 Thereafter 5 77 Total lease payments $ 16,813 $ 944 Less imputed interest (1,724 ) (84 ) Total $ 15,089 $ 860

Stock Incentive Plan and Othe_2

Stock Incentive Plan and Other Equity Activity (Tables)	6 Months Ended
	Jun. 30, 2019
Stockholders' Equity Note [Abstract]
Schedule of Share Grants and Issuances	During the six months ended June 30, 2019 , the Company had the following share issuances associated with the Stock Incentive Plan: Shares RSA (issued upon grant) 52 RSUs (issued upon vesting) 73 PSUs (issued upon vesting) 54 Total shares issued 179 During the six months ended June 30, 2019 , the Company had the following share grants associated with the Stock Incentive Plan: Shares Weighted Average Grant-Date Fair Value per Share RSAs 52 $ 12.06 RSUs 138 $ 10.96 PSUs 185 $ 10.89 Total shares granted 375 —

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: Net income attributable to Sterling common stockholders $ 7,828 $ 8,174 $ 9,643 $ 10,663 Denominator: Weighted average common shares outstanding — basic 26,338 26,887 26,357 26,881 Shares for dilutive unvested stock and warrants 285 238 300 281 Weighted average common shares outstanding — diluted 26,623 27,125 26,657 27,162 Basic net income per share attributable to Sterling common stockholders $ 0.30 $ 0.30 $ 0.37 $ 0.40 Diluted net income per share attributable to Sterling common stockholders $ 0.29 $ 0.30 $ 0.36 $ 0.39

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2019
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 and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Revenues Heavy Civil Construction $ 228,130 $ 223,283 $ 409,314 $ 410,524 Residential Construction 35,956 45,451 78,721 80,702 Total Revenues $ 264,086 $ 268,734 $ 488,035 $ 491,226 Operating Income Heavy Civil Construction $ 6,146 $ 6,395 $ 5,299 $ 8,340 Residential Construction 5,038 5,754 10,605 10,488 Total Operating Income $ 11,184 $ 12,149 $ 15,904 $ 18,828

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2019
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: Six Months Ended June 30, 2019 2018 Accounts receivable, including retainage $ (12,787 ) $ (30,534 ) Contracts in progress, net (14,190 ) (3,346 ) Receivables from and equity in construction joint ventures (3,661 ) (386 ) Other assets 128 1,562 Accounts payable 1,916 (1,073 ) Accrued compensation and other liabilities 2,990 1,761 Member’s interest subject to mandatory redemption and undistributed earnings (512 ) 451 Changes in operating assets and liabilities $ (26,116 ) $ (31,565 )

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Operating lease right-of-use assets	$ 14,995	$ 13,600
Current portion of long-term lease obligations	7,059	6,200
Long-term lease obligations	$ 8,030	$ 7,400
Weighted average remaining lease terms	2 years 9 months 4 days
Operating lease weighted average discount rate	6.00%
Other current assets
Property, Plant and Equipment [Line Items]
Restricted cash, current	$ 3,200		$ 3,900
Minimum
Property, Plant and Equipment [Line Items]
Warranty, term	1 year
Maximum
Property, Plant and Equipment [Line Items]
Warranty, term	2 years

Revenue From Contracts With C_3

Revenue From Contracts With Customers - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)contract	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)contract	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Disaggregation of Revenue [Line Items]
Remaining performance obligation	$ 909		$ 909
Heavy Civil Construction
Disaggregation of Revenue [Line Items]
Number of contracts (more than) | contract	150		150
Costs and Estimated Earnings in Excess of Billings
Disaggregation of Revenue [Line Items]
Contracts receivable unpaid project contract price	$ 15.7		$ 15.7		$ 9.3
Operating income (Loss)
Disaggregation of Revenue [Line Items]
Estimated construction gain (loss) before tax	$ 3.5	$ 0.3	$ 3.3	$ 1.7
Transferred over Time | Product Concentration Risk | Revenue from Contract with Customer
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	86.00%	83.00%	84.00%	84.00%
Transferred at Point in Time | Product Concentration Risk | Revenue from Contract with Customer
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	14.00%	17.00%	16.00%	16.00%
Minimum
Disaggregation of Revenue [Line Items]
Revenue recognition, contract term			12 months
Maximum
Disaggregation of Revenue [Line Items]
Revenue recognition, contract term			36 months

Revenue From Contracts With C_4

Revenue From Contracts With Customers - Performance Obligations (Details) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Remaining performance obligation expected to be recognized over next twelve months	70.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period	12 months

Revenue From Contracts With C_5

Revenue From Contracts With Customers - By Major Market End (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total Revenue	$ 264,086	$ 268,734	$ 488,035	$ 491,226
Heavy Civil Construction
Disaggregation of Revenue [Line Items]
Total Revenue	228,130	223,283	409,314	410,524
Heavy Civil Construction | Heavy Highway
Disaggregation of Revenue [Line Items]
Total Revenue	129,964	126,554	223,574	233,962
Heavy Civil Construction | Commercial
Disaggregation of Revenue [Line Items]
Total Revenue	28,575	29,109	59,425	57,628
Heavy Civil Construction | Aviation
Disaggregation of Revenue [Line Items]
Total Revenue	37,061	27,832	66,998	51,084
Heavy Civil Construction | Water Containment and Treatment
Disaggregation of Revenue [Line Items]
Total Revenue	15,515	15,521	30,749	30,516
Heavy Civil Construction | Other Revenue
Disaggregation of Revenue [Line Items]
Total Revenue	$ 17,015	$ 24,267	$ 28,568	$ 37,334

Revenue From Contracts With C_6

Revenue From Contracts With Customers - By Contract Type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total Revenue	$ 264,086	$ 268,734	$ 488,035	$ 491,226
Heavy Civil Construction
Disaggregation of Revenue [Line Items]
Total Revenue	228,130	223,283	409,314	410,524
Heavy Civil Construction | Fixed Unit Price
Disaggregation of Revenue [Line Items]
Total Revenue	185,297	194,485	326,516	354,721
Heavy Civil Construction | Lump Sum and Other
Disaggregation of Revenue [Line Items]
Total Revenue	$ 42,833	$ 28,798	$ 82,798	$ 55,803

Consolidated 50% Owned Subsid_3

Consolidated 50% Owned Subsidiaries - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Noncontrolling Interest [Line Items]
Ownership interest in subsidiaries	50.00%		50.00%
Members’ interest subject to mandatory redemption	$ 40,000		$ 40,000		$ 40,000
Total disability insurance policies, per policy amount	20,000		20,000
Myers
Noncontrolling Interest [Line Items]
Net accumulated earnings	1,500	$ 4,700	2,700	$ 5,300
Myers | Variable Interest Entity, Primary Beneficiary
Noncontrolling Interest [Line Items]
Members’ interest subject to mandatory redemption	$ 20,000		$ 20,000

Consolidated 50% Owned Subsid_4

Consolidated 50% Owned Subsidiaries - Components of Noncontrolling Interest (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Noncontrolling Interest [Abstract]
Members’ interest subject to mandatory redemption	$ 40,000	$ 40,000
Net accumulated earnings	8,831	9,343
Total liability	$ 48,831	$ 49,343

Consolidated 50% Owned Subsid_5

Consolidated 50% Owned Subsidiaries Consolidated 50% Owned Subsidiaries - Balance Sheet Information (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Cash and cash equivalents	$ 71,730		$ 94,095
Accounts receivable, including retainage	157,813		145,026
Other current assets	7,951		8,074
Total current assets	309,023		302,616
Property and equipment, net	49,217		51,999
Operating lease right-of-use assets	14,995	$ 13,600
Goodwill	85,231		85,231
Total assets	499,895		482,573
Accounts payable	101,342		99,426
Other current liabilities	5,183		4,676
Total current liabilities	198,532		179,174
Other long-term liabilities	1,101		1,229
Total liabilities	325,202		310,313
Variable Interest Entity, Primary Beneficiary
Schedule of Equity Method Investments [Line Items]
Cash and cash equivalents	6,195		8,745
Accounts receivable, including retainage	27,011		24,109
Other current assets	14,959		14,533
Total current assets	48,165		47,387
Property and equipment, net	6,369		7,219
Operating lease right-of-use assets	3,232
Goodwill	1,501		1,501
Total assets	59,267		56,107
Accounts payable	23,672		22,211
Other current liabilities	10,583		9,811
Total current liabilities	34,255		32,022
Other long-term liabilities	1,680		1,976
Total liabilities	$ 35,935		$ 33,998

Construction Joint Ventures - B

Construction Joint Ventures - Balance Sheet Information (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Current assets	$ 309,023	$ 302,616
Less current liabilities	(198,532)	(179,174)
Sterling’s receivables from and equity in noncontrolling construction joint ventures	14,381	10,720
Joint Ventures
Schedule of Equity Method Investments [Line Items]
Current assets	95,991	64,815
Less current liabilities	(98,192)	(74,543)
Net liabilities	(2,201)	(9,728)
Sterling’s receivables from and equity in noncontrolling construction joint ventures	$ 14,381	$ 10,720

Construction Joint Ventures - I

Construction Joint Ventures - Income Statement Information (Details) - Joint Ventures - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule of Equity Method Investments [Line Items]
Revenues	$ 55,306	$ 25,463	$ 86,690	$ 56,820
Income before tax	8,844	2,192	10,813	5,596
Sterling’s noncontrolling interest:
Revenues	25,971	12,564	41,655	27,629
Income before tax	$ 3,116	$ 1,167	$ 4,100	$ 2,858

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 164,338	$ 161,133
Less accumulated depreciation	(115,121)	(109,134)
Total property and equipment, net	49,217	51,999
Construction and transportation equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	147,796	144,630
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	11,195	11,072
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,720	2,720
Office equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,627	$ 2,711

Other Intangible Assets (Detail

Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life		22 years
Gross Carrying Amount	$ 46,617	$ 46,617	$ 46,617
Accumulated Amortization	(5,399)	(5,399)	(4,199)
Amortization of intangible assets	600	$ 1,200
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life		23 years
Gross Carrying Amount	40,823	$ 40,823	40,823
Accumulated Amortization	(4,062)	$ (4,062)	(3,159)
Trade Names
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life		13 years
Gross Carrying Amount	5,307	$ 5,307	5,307
Accumulated Amortization	(1,181)	$ (1,181)	(919)
Noncompete Agreements
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life		7 years
Gross Carrying Amount	487	$ 487	487
Accumulated Amortization	$ (156)	$ (156)	$ (121)

Debt - Long-term Debt (Details)

Debt - Long-term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total debt	$ 84,327	$ 88,755
Less - Current maturities of long-term debt	(12,128)	(2,899)
Less - Unamortized deferred debt costs	(5,702)	(6,739)
Total long-term debt, net of unamortized debt costs	66,497	79,117
Notes and deferred payments to sellers, Tealstone acquisition
Debt Instrument [Line Items]
Notes payable	11,710	13,572
Notes payable for transportation and construction equipment and other
Debt Instrument [Line Items]
Notes payable	1,015	612
Oaktree facility | Senior secured term loans | Equipment-based facility
Debt Instrument [Line Items]
Oaktree Facility	$ 71,602	$ 74,571

Debt - Narrative (Details)

Debt - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Notes and deferred payments to sellers, Tealstone acquisition
Debt Instrument [Line Items]
Deferred payments			$ 2,400,000
Promissory notes issued to the sellers			5,000,000
Deferred cash payments due	$ 7,500,000		7,500,000
Notes and deferred payments to sellers			11,600,000
Accretion expense	$ 300,000	$ 300,000	$ 600,000	$ 600,000
Notes and deferred payments to sellers, Tealstone acquisition | Measurement Input, Discount Rate
Debt Instrument [Line Items]
Fair value inputs, discount rate	0.12		0.12
Notes and deferred payments to sellers, Tealstone acquisition
Debt Instrument [Line Items]
Notes Payable	$ 11,710,000		$ 11,710,000		$ 13,572,000
Notes payable for transportation and construction equipment and other
Debt Instrument [Line Items]
Notes Payable	1,015,000		1,015,000		612,000
Senior secured term loans | Oaktree facility | Equipment-based facility
Debt Instrument [Line Items]
Oaktree Facility	71,602,000		$ 71,602,000		$ 74,571,000
Debt instrument, term			5 years
Senior secured term loans | Term loan | Loan and security agreement
Debt Instrument [Line Items]
Debt instrument face amount	$ 85,000,000		$ 85,000,000
Loan prepayment offer required to make quarterly, percentage	75.00%		75.00%
Debt instrument, financial covenants, maximum ratio of secured indebtedness to EBITDA, period one			1.9
Debt Instrument, financial covenants, maximum ratio of secured indebtedness to EBITDA, period two			1.8
Debt Instrument, financial covenants, minimum daily cash collateral, period two	$ 15,000,000		$ 15,000,000
Debt Instrument, financial covenants, minimum rolling four quarter gross margin in contract backlog, period two			70,000,000
Debt instrument, financial covenants, maximum incurrence of net capital expenditures during each of four consecutive fiscal quarters			15,000,000
Debt instrument, financial covenants, minimum bonding capacity	$ 1,000,000,000		1,000,000,000
Debt instrument, financial covenants, minimum EBITDA during each four consecutive fiscal quarters			$ 12,000,000
Senior secured term loans | Term loan | Loan and security agreement | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			8.75%
Notes payable for transportation and construction equipment and other | Minimum
Debt Instrument [Line Items]
Debt instrument, term			3 years
Debt instrument, interest rate, stated percentage	2.99%		2.99%
Notes payable for transportation and construction equipment and other | Maximum
Debt Instrument [Line Items]
Debt instrument, term			5 years
Debt instrument, interest rate, stated percentage	6.92%		6.92%

Lease Obligations (Details)

Lease Obligations (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Lease termination period		10 years
Lease, Cost [Abstract]
Operating lease cost	$ 1,960	$ 4,171
Short-term lease cost	3,269	8,012
Finance lease cost:
Amortization of right-of-use assets	39	71
Interest on lease liabilities	1	3
Total finance lease cost	40	74
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases		4,466
Operating cash flows from finance leases		3
Financing cash flows from finance leases		71
Right-of-use assets obtained in exchange for lease obligations (noncash):
Operating leases		6,311
Finance leases		770
Assets and Liabilities, Lessee [Abstract]
Operating lease right-of-use assets	14,995	14,995	$ 13,600
Current portion of long-term lease obligations	7,059	7,059	6,200
Long-term lease obligations	8,030	8,030	$ 7,400
Total operating lease liabilities	15,089	15,089
Property and equipment, at cost	1,433	1,433
Accumulated depreciation	(347)	(347)
Property and equipment, net	1,086	1,086
Current maturities of long-term debt	234	234
Long-term debt	626	626
Total finance lease liabilities	$ 860	$ 860
Weighted Average Remaining Lease Term: Operating leases	2 years 9 months 4 days	2 years 9 months 4 days
Weighted Average Remaining Lease Term: Financing leases	4 years 4 months 10 days	4 years 4 months 10 days
Weighted Average Discount Rate: Operating lease	6.00%	6.00%
Weighted Average Discount Rate: Financing lease	4.20%	4.20%
Operating Lease Liabilities, Payments Due [Abstract]
2019 (excluding the six months ended June 30, 2019)	$ 4,206	$ 4,206
2020	5,885	5,885
2021	4,231	4,231
2022	2,087	2,087
2023	399	399
Thereafter	5	5
Total lease payments	16,813	16,813
Less imputed interest	(1,724)	(1,724)
Total operating lease liabilities	15,089	15,089
Finance Lease Liabilities, Payments, Due [Abstract]
2019 (excluding the six months ended June 30, 2019)	157	157
2020	209	209
2021	186	186
2022	161	161
2023	154	154
Thereafter	77	77
Total lease payments	944	944
Less imputed interest	(84)	(84)
Total finance lease liabilities	$ 860	$ 860
Minimum
Lessee, Lease, Description [Line Items]
Lease renewal term		1 month
Maximum
Lessee, Lease, Description [Line Items]
Lease renewal term		5 years

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Current income tax expense (benefit)	$ 86	$ 97	$ 108	$ 138
Deferred Tax Assets, Valuation Allowance	31,700		31,700		$ 31,700
Deferred tax expense	$ 620		$ 761	$ 0

Stock Incentive Plan and Othe_3

Stock Incentive Plan and Other Equity Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Sale of Stock [Line Items]
Shares granted (in shares)					375
Shares issued under share-based compensation (in shares)					179
Stock-based compensation expense					$ 1,670	$ 1,383
Purchase of treasury stock	$ 0	$ 3,201
Shares withheld for taxes	$ 98	$ 564	$ 107	$ 194
Common Stock
Sale of Stock [Line Items]
Purchase of treasury stock (in shares)					250
Purchase of treasury stock					$ 3,201
Shares withheld for taxes (in shares)	7				59
Shares withheld for taxes	$ 98				$ 662
Additional Paid in Capital
Sale of Stock [Line Items]
Stock-based compensation expense	649		766		$ 1,670	$ 1,383
Shares withheld for taxes	$ 98		$ 108	$ 193
Common Stock
Sale of Stock [Line Items]
Purchase of treasury stock (in shares)		250
Shares withheld for taxes (in shares)	7	52	10	13
Shares withheld for taxes			$ (1)	$ 1
RSAs
Sale of Stock [Line Items]
Shares granted (in shares)					52
Weighted Average Grant-Date Fair Value per Share (in dollars per share)					$ 12.06
RSUs
Sale of Stock [Line Items]
Shares granted (in shares)					138
Weighted Average Grant-Date Fair Value per Share (in dollars per share)					$ 10.96
Shares issued under share-based compensation (in shares)					73
PSUs
Sale of Stock [Line Items]
Shares granted (in shares)					185
Weighted Average Grant-Date Fair Value per Share (in dollars per share)					$ 10.89
Shares issued under share-based compensation (in shares)					54

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net income attributable to Sterling common stockholders	$ 7,828	$ 8,174	$ 9,643	$ 10,663
Denominator:
Weighted average common shares outstanding - basic (in shares)	26,338	26,887	26,357	26,881
Shares for dilutive unvested stock and warrants (in shares)	285	238	300	281
Weighted average common shares outstanding and incremental shares assumed repurchased - diluted (in shares)	26,623	27,125	26,657	27,162
Basic net income per share attributable to Sterling common stockholders (in dollars per share)	$ 0.30	$ 0.30	$ 0.37	$ 0.40
Diluted net income per share attributable to Sterling common stockholders (in dollars per share)	$ 0.29	$ 0.30	$ 0.36	$ 0.39

Segment Information - Narrative

Segment Information - Narrative (Details)	6 Months Ended
	Jun. 30, 2019segment
Segment Reporting [Abstract]
Number of operating segments	2

Segment Information - Revenue,

Segment Information - Revenue, Operating Income, and Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Total Revenue	$ 264,086	$ 268,734	$ 488,035	$ 491,226
Operating income	11,184	12,149	15,904	18,828
Heavy Civil Construction
Segment Reporting Information [Line Items]
Total Revenue	228,130	223,283	409,314	410,524
Operating income	6,146	6,395	5,299	8,340
Residential Construction
Segment Reporting Information [Line Items]
Total Revenue	35,956	45,451	78,721	80,702
Operating income	$ 5,038	$ 5,754	$ 10,605	$ 10,488

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Accounts receivable, including retainage	$ (12,787)	$ (30,534)
Contracts in progress, net	(14,190)	(3,346)
Receivables from and equity in construction joint ventures	(3,661)	(386)
Other assets	128	1,562
Accounts payable	1,916	(1,073)
Accrued compensation and other liabilities	2,990	1,761
Member’s interest subject to mandatory redemption and undistributed earnings	(512)	451
Changes in operating assets and liabilities	$ (26,116)	$ (31,565)