Organization, Business and Basis of Presentation (Policies)	6 Months Ended
Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interim Consolidated Financial Information	Interim Consolidated Financial Information The accompanying unaudited consolidated financial statements of the Company were prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial reporting pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the rules and regulations of the SEC. The Company believes that the disclosures made are adequate to make the information presented not misleading. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, necessary to fairly state the financial position, results of operations, comprehensive income, stockholders’ equity and cash flows with respect to the interim consolidated financial statements, have been included. The consolidated balance sheet as of December 31, 2020 has been derived from the audited financial statements as of that date. The results of operations and comprehensive income are not necessarily indicative of the results for the full year or the results for any future periods. These financial statements should be read in conjunction with the audited financial statements and related notes for the year ended December 31, 2020, included in the Company’s Annual Report on Form 10-K, which was filed with the SEC on March 3, 2021 (the "2020 Annual Report").
Joint Ventures and Noncontrolling Interests	Joint Ventures and Noncontrolling Interests The Company accounts for investments in joint ventures using the proportionate consolidation method for income statement reporting and under the equity method for balance sheet reporting, unless the Company has a controlling interest causing the joint venture to be consolidated with equity owned by other joint venture partners recorded as noncontrolling interests. Under the proportionate consolidation method, joint venture activity is allocated to the appropriate line items found on the consolidated statements of operations in proportion to the percentage of participation the Company has in the joint venture. Under the equity method the net investment in joint ventures is stated as a single item on the Company’s consolidated balance sheets. If an investment in a joint venture contains a recourse or unfunded commitments to provide additional equity, distributions and/or losses in excess of the investment, a liability is recorded in other current liabilities on the Company’s consolidated balance sheets. For joint ventures in which the Company does not have a controlling interest, the Company’s share of any profits and assets and its share of any losses and liabilities are recognized based on the Company’s stated percentage partnership interest in the joint venture, and are normally recorded by the Company one month in arrears. The investments in joint ventures are recorded at cost and the carrying amounts are adjusted to recognize the Company’s proportionate share of cumulative income or loss, additional contributions made and dividends and capital distributions received. The Company records the effect of any impairment or any other-than-temporary decrease in the value of the joint venture investment as incurred, which may or may not be one month in arrears, depending on when the Company obtains the joint venture activity information. Additionally, the Company continually assesses the fair value of its investment in unconsolidated joint ventures despite using information that is one month in arrears for regular reporting purposes. The Company includes only its percentage ownership of each joint venture in its backlog. The Company is the majority controlling interest in a joint venture. As a result, the Company has consolidated the carrying value of the joint ventures’ assets and liabilities and results of operations in the Company’s consolidated financial statements. The equity owned by the other joint venture partners has been recorded as noncontrolling interest in the Company’s consolidated balance sheets, consolidated statements of stockholders’ equity, and their portions, if material, of net income (loss) and other comprehensive income shown as net income or other comprehensive income attributable to noncontrolling interest in the Company’s consolidated statements of operations and other comprehensive income. Additionally, the joint venture associated with the Company’s noncontrolling interest is a partnership, and consequently, the tax effect of only the Company’s share of the joint venture income is recognized by the Company. The majority controlled joint venture made no distributions to its partners, and the Company made no capital contributions to the joint venture, during the three and six months ended June 30, 2021. Additionally, there have been no changes in ownership during the three and six months ended June 30, 2021. The project associated with this joint venture was substantially completed in 2019.
Foreign Currency	Foreign Currency The functional currency for the Company’s Canadian operations is the Canadian dollar. Assets and liabilities denominated in Canadian dollars are translated into U.S. dollars at the end-of-period exchange rate. Revenues and expenses are translated using average exchange rates for the periods reported. Equity accounts are translated at historical rates. Cumulative translation adjustments are included as a separate component of accumulated other comprehensive income in shareholders’ equity. Foreign currency transaction gains and losses, arising primarily from changes in exchange rates on short-term monetary assets and liabilities, and ineffective long-term monetary assets and liabilities are recorded in the “other income, net” line on the Company’s consolidated statements of operations. Foreign currency losses, recorded in other income, net, for the six months ended June 30, 2021 were $0.1 million. Foreign currency gains, recorded in other income, net, for the six months ended June 30, 2020 were not significant. Effective foreign currency transaction gains and losses, arising primarily from long-term monetary assets and liabilities, are recorded in the foreign currency translation adjustment line on the Company’s consolidated statements of comprehensive income.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. 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 revenues and expenses during the period reported. Actual results could differ from those estimates. The most significant estimates are related to estimates of costs to complete contracts, pending change orders and claims, shared savings, insurance reserves, income tax reserves, estimates surrounding stock-based compensation, the recoverability of goodwill and intangibles and allowance for doubtful accounts. The Company estimates a cost accrual every quarter that represents costs incurred but not invoiced for services performed or goods delivered during the period, and estimates revenue from the contract cost portion of these accruals based on current gross margin rates to be consistent with its cost method of revenue recognition. As of June 30, 2021 and 2020, the Company had recognized revenues of $6.0 million and $40.1 million, respectively, related to significant change orders and/or claims that had been included as contract price adjustments on certain contracts, some of which are multi-year projects. These change orders and/or claims are in the process of being negotiated in the normal course of business, and a portion of these recognized revenues had been included in multiple periods. The cost-to-cost method of accounting requires the Company to make estimates about the expected revenue and gross profit on each of its contracts in process. During the three months ended June 30, 2021, changes in estimates pertaining to certain projects increased consolidated gross margin by 0.8%, which resulted in increases in operating income of $5.1 million, net income of $3.6 million and diluted earnings per common share of $0.21. During the six months ended June 30, 2021, changes in estimates pertaining to certain projects increased consolidated gross margin by 0.3%, which resulted in increases in operating income of $3.9 million, net income of $2.7 million and diluted earnings per common share of $0.16. During the three months ended June 30, 2020, changes in estimates pertaining to certain projects increased consolidated gross margin by 0.2%, which resulted in increases in operating income of $1.2 million, net income of $0.9 million and diluted earnings per common share of $0.05. During the six months ended June 30, 2020, changes in estimates pertaining to certain projects decreased consolidated gross margin by 0.1%, which resulted in decreases in operating income of $0.7 million, net income of $0.5 million and diluted earnings per common share of $0.03.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Changes to U.S. GAAP are typically established by the Financial Accounting Standards Board (“FASB”) in the form of accounting standards updates (“ASUs”) to the FASB’s Accounting Standards Codification (“ASC”). The Company considers the applicability and impact of all ASUs. The Company, based on its assessment, determined that any recently issued or proposed ASUs not listed below are either not applicable to the Company or adoption will have minimal impact on its consolidated financial statements. Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes, eliminates certain exceptions within ASC 740, Income Taxes, and clarifies certain aspects of the current guidance to promote consistent application among reporting entities. The Company adopted this ASU in January 2021 and there was no effect on the consolidated financial statements or disclosures.
Fair Value Measurements	Fair Value MeasurementsThe Company uses the three-tier hierarchy of fair value measurement, which prioritizes the inputs used in measuring fair value based upon their degree of availability in external active markets. These tiers include: Level 1 (the highest priority), defined as observable inputs, such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3 (the lowest priority), defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.
Earnings Per Share	Earnings Per ShareThe Company computes earnings per share using the treasury stock method. Under the treasury stock method, basic earnings per share are computed by dividing net income available to stockholders by the weighted average number of common shares outstanding during the period, and diluted earnings per share are computed by dividing net income available to stockholders by the weighted average number of common shares outstanding during the period plus all potentially dilutive common stock equivalents, except in cases where the effect of the common stock equivalent would be anti-dilutive.

Organization, Business and Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Interim Consolidated Financial Information

The accompanying unaudited consolidated financial statements of the Company were prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial reporting pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the rules and regulations of the SEC. The Company believes that the disclosures made are adequate to make the information presented not misleading. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, necessary to fairly state the financial position, results of operations, comprehensive income, stockholders’ equity and cash flows with respect to the interim consolidated financial statements, have been included. The consolidated balance sheet as of December 31, 2020 has been derived from the audited financial statements as of that date. The results of operations and comprehensive income are not necessarily indicative of the results for the full year or the results for any future periods. These financial statements should be read in conjunction with the audited financial statements and related notes for the year ended December 31, 2020, included in the Company’s Annual Report on Form 10-K, which was filed with the SEC on March 3, 2021 (the "2020 Annual Report").

Joint Ventures and Noncontrolling Interests

The Company accounts for investments in joint ventures using the proportionate consolidation method for income statement reporting and under the equity method for balance sheet reporting, unless the Company has a controlling interest causing the joint venture to be consolidated with equity owned by other joint venture partners recorded as noncontrolling interests. Under the proportionate consolidation method, joint venture activity is allocated to the appropriate line items found on the consolidated statements of operations in proportion to the percentage of participation the Company has in the joint venture. Under the equity method the net investment in joint ventures is stated as a single item on the Company’s consolidated balance sheets. If an investment in a joint venture contains a recourse or unfunded commitments to provide additional equity, distributions and/or losses in excess of the investment, a liability is recorded in other current liabilities on the Company’s consolidated balance sheets.

For joint ventures in which the Company does not have a controlling interest, the Company’s share of any profits and assets and its share of any losses and liabilities are recognized based on the Company’s stated percentage partnership interest in the joint venture, and are normally recorded by the Company one month in arrears. The investments in joint ventures are recorded at cost and the carrying amounts are adjusted to recognize the Company’s proportionate share of cumulative income or loss, additional contributions made and dividends and capital distributions received. The Company records the effect of any impairment or any other-than-temporary decrease in the value of the joint venture investment as incurred, which may or may not be one month in arrears, depending on when the Company obtains the joint venture activity information. Additionally, the Company continually assesses the fair value of its investment in unconsolidated joint ventures despite using information that is one month in arrears for regular reporting purposes. The Company includes only its percentage ownership of each joint venture in its backlog.

The Company is the majority controlling interest in a joint venture. As a result, the Company has consolidated the carrying value of the joint ventures’ assets and liabilities and results of operations in the Company’s consolidated financial statements. The equity owned by the other joint venture partners has been recorded as noncontrolling interest in the Company’s consolidated balance sheets, consolidated statements of stockholders’ equity, and their portions, if material, of net income (loss) and other comprehensive income shown as net income or other comprehensive income attributable to noncontrolling interest in the Company’s consolidated statements of operations and other comprehensive income. Additionally, the joint venture associated with the Company’s noncontrolling interest is a partnership, and consequently, the tax effect of only the Company’s share of the joint venture income is recognized by the Company. The majority controlled joint venture made no distributions to its partners, and the Company made no capital contributions to the joint venture, during the three and six months ended June 30, 2021. Additionally, there have been no changes in ownership during the three and six months ended June 30, 2021. The project associated with this joint venture was substantially completed in 2019.

Foreign Currency

The functional currency for the Company’s Canadian operations is the Canadian dollar. Assets and liabilities denominated in Canadian dollars are translated into U.S. dollars at the end-of-period exchange rate. Revenues and expenses are translated using average exchange rates for the periods reported. Equity accounts are translated at historical rates. Cumulative translation adjustments are included as a separate component of accumulated other comprehensive income in shareholders’ equity. Foreign currency transaction gains and losses, arising primarily from changes in exchange rates on short-term monetary assets and liabilities, and ineffective long-term monetary assets and liabilities are recorded in the “other income, net” line on the Company’s consolidated statements of operations. Foreign currency losses, recorded in other income, net, for the six months ended June 30, 2021 were $0.1 million. Foreign currency gains, recorded in other income, net, for the six months ended June 30, 2020 were not significant. Effective foreign currency transaction gains and losses, arising primarily from long-term monetary assets and liabilities, are recorded in the foreign currency translation adjustment line on the Company’s consolidated statements of comprehensive income.

Use of Estimates

The preparation of financial statements in conformity with U.S. 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 revenues and expenses during the period reported. Actual results could differ from those estimates.

The most significant estimates are related to estimates of costs to complete contracts, pending change orders and claims, shared savings, insurance reserves, income tax reserves, estimates surrounding stock-based compensation, the recoverability of goodwill and intangibles and allowance for doubtful accounts. The Company estimates a cost accrual every quarter that represents costs incurred but not invoiced for services performed or goods delivered during the period, and estimates revenue from the contract cost portion of these accruals based on current gross margin rates to be consistent with its cost method of revenue recognition.

As of June 30, 2021 and 2020, the Company had recognized revenues of $6.0 million and $40.1 million, respectively, related to significant change orders and/or claims that had been included as contract price adjustments on certain contracts, some of which are multi-year projects. These change orders and/or claims are in the process of being negotiated in the normal course of business, and a portion of these recognized revenues had been included in multiple periods.

The cost-to-cost method of accounting requires the Company to make estimates about the expected revenue and gross profit on each of its contracts in process. During the three months ended June 30, 2021, changes in estimates pertaining to certain projects increased consolidated gross margin by 0.8%, which resulted in increases in operating income of $5.1 million, net income of $3.6 million and diluted earnings per common share of $0.21. During the six months ended June 30, 2021, changes in estimates pertaining to certain projects increased consolidated gross margin by 0.3%, which resulted in increases in operating income of $3.9 million, net income of $2.7 million and diluted earnings per common share of $0.16.

During the three months ended June 30, 2020, changes in estimates pertaining to certain projects increased consolidated gross margin by 0.2%, which resulted in increases in operating income of $1.2 million, net income of $0.9 million and diluted earnings per common share of $0.05. During the six months ended June 30, 2020, changes in estimates pertaining to certain projects decreased consolidated gross margin by 0.1%, which resulted in decreases in operating income of $0.7 million, net income of $0.5 million and diluted earnings per common share of $0.03.

Recent Accounting Pronouncements

Changes to U.S. GAAP are typically established by the Financial Accounting Standards Board (“FASB”) in the form of accounting standards updates (“ASUs”) to the FASB’s Accounting Standards Codification (“ASC”). The Company considers the applicability and impact of all ASUs. The Company, based on its assessment, determined that any recently issued or proposed ASUs not listed below are either not applicable to the Company or adoption will have minimal impact on its consolidated financial statements.

Recently Adopted Accounting Pronouncements

In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes, eliminates certain exceptions within ASC 740, Income Taxes, and clarifies certain aspects of the current guidance to promote consistent application among reporting entities. The Company adopted this ASU in January 2021 and there was no effect on the consolidated financial statements or disclosures.

Fair Value Measurements

Fair Value MeasurementsThe Company uses the three-tier hierarchy of fair value measurement, which prioritizes the inputs used in measuring fair value based upon their degree of availability in external active markets. These tiers include: Level 1 (the highest priority), defined as observable inputs, such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3 (the lowest priority), defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.

Earnings Per Share

Earnings Per ShareThe Company computes earnings per share using the treasury stock method. Under the treasury stock method, basic earnings per share are computed by dividing net income available to stockholders by the weighted average number of common shares outstanding during the period, and diluted earnings per share are computed by dividing net income available to stockholders by the weighted average number of common shares outstanding during the period plus all potentially dilutive common stock equivalents, except in cases where the effect of the common stock equivalent would be anti-dilutive.