Variable Interest Entities	12 Months Ended
Dec. 31, 2019
Variable Interest Entities [Abstract]
Variable Interest Entities	14. Variable Interest Entities (VIEs) The Company may form joint ventures or partnerships with third parties for the execution of projects. In accordance with ASC 810, the Company assesses its partnerships and joint ventures at inception to determine if any meet the qualifications of a VIE. The Company considers a joint venture a VIE if either (a) the total equity investment is not sufficient to permit the entity to finance its activities without additional subordinated financial support, (b) characteristics of a controlling financial interest are missing (either the ability to make decisions through voting or other rights, the obligation to absorb the expected losses of the entity or the right to receive the expected residual returns of the entity), or (c) the voting rights of the equity holders are not proportional to their obligations to absorb the expected losses of the entity and/or their rights to receive the expected residual returns of the entity, and substantially all of the entity’s activities either involve or are conducted on behalf of an investor that has disproportionately few voting rights. Upon the occurrence of certain events outlined in ASC 810, the Company reassesses its initial determination of whether the joint venture is a VIE. ASC 810 also requires the Company to determine whether it is the primary beneficiary of the VIE. The Company concludes that it is the primary beneficiary and consolidates the VIE if the Company has both (a) the power to direct the economically significant activities of the VIE and (b) the obligation to absorb losses of, or the right to receive benefits from, the VIE that could potentially be significant to the VIE. The Company considers the contractual agreements that define the ownership structure, distribution of profits and losses, risks, responsibilities, indebtedness, voting rights and board representation of the respective parties in determining if the Company is the primary beneficiary. The Company also considers all parties that have direct or implicit variable interests when determining whether it is the primary beneficiary. In accordance with ASC 810, management’s assessment of whether the Company is the primary beneficiary of a VIE is performed continuously. As of December 31, 2019, the Company had unconsolidated VIE-related current assets and liabilities of $1.5 million and $1.4 million, respectively, included in the Company’s Consolidated Balance Sheet. As of December 31, 2018, the Company had unconsolidated VIE-related current assets and liabilities of $4.0 million and $3.8 million, respectively, included in the Company’s Consolidated Balance Sheet. The Company’s maximum exposure to loss as a result of its investments in unconsolidated VIEs is typically limited to the aggregate of the carrying value of the investment and future funding commitments. There were no future funding requirements for the unconsolidated VIEs as of December 31, 2019. As of December 31, 2019, the Company’s Consolidated Balance Sheet included current and noncurrent assets of $365.0 million and $52.0 million, respectively, as well as current liabilities of $556.1 million related to the operations of its consolidated VIEs. As of December 31, 2018, the Company’s Consolidated Balance Sheet included current and noncurrent assets of $173.9 million and $51.5 million, respectively, as well as current liabilities of $319.9 million related to the operations of its consolidated VIEs. Below is a discussion of some of the Company’s more significant or unique VIEs. The Company established a joint venture to construct the Purple Line Extension Section 2 (Tunnels and Stations) and Section 3 (Stations) mass-transit projects in Los Angeles, California with a combined value of approximately $2.8 billion. The Company has a 75% interest in the joint venture with the remaining 25% held by O&G Industries, Inc. (“O&G”). The joint venture was initially financed with contributions from the partners and, per the terms of the joint venture agreement, the partners may be required to provide additional capital contributions in the future. The Company has determined that this joint venture is a VIE for which the Company is the primary beneficiary. The Company also established a joint venture with Parsons Corporation (“Parsons”) to construct the Newark Liberty International Airport Terminal One project, a $1.4 billion transportation infrastructure project in Newark, New Jersey. The Company has an 80% interest in the joint venture with the remaining 20% held by Parsons. The joint venture was initially financed with contributions from the partners and, per the terms of the joint venture agreement, the partners may be required to provide additional capital contributions in the future. The Company has determined that this joint venture is a VIE for which the Company is the primary beneficiary.

Variable Interest Entities

12 Months Ended

Dec. 31, 2019

Variable Interest Entities [Abstract]

14. Variable Interest Entities (VIEs)

The Company may form joint ventures or partnerships with third parties for the execution of projects. In accordance with ASC 810, the Company assesses its partnerships and joint ventures at inception to determine if any meet the qualifications of a VIE. The Company considers a joint venture a VIE if either (a) the total equity investment is not sufficient to permit the entity to finance its

activities without additional subordinated financial support, (b) characteristics of a controlling financial interest are missing (either the ability to make decisions through voting or other rights, the obligation to absorb the expected losses of the entity or the right to receive the expected residual returns of the entity), or (c) the voting rights of the equity holders are not proportional to their obligations to absorb the expected losses of the entity and/or their rights to receive the expected residual returns of the entity, and substantially all of the entity’s activities either involve or are conducted on behalf of an investor that has disproportionately few voting rights. Upon the occurrence of certain events outlined in ASC 810, the Company reassesses its initial determination of whether the joint venture is a VIE.

ASC 810 also requires the Company to determine whether it is the primary beneficiary of the VIE. The Company concludes that it is the primary beneficiary and consolidates the VIE if the Company has both (a) the power to direct the economically significant activities of the VIE and (b) the obligation to absorb losses of, or the right to receive benefits from, the VIE that could potentially be significant to the VIE. The Company considers the contractual agreements that define the ownership structure, distribution of profits and losses, risks, responsibilities, indebtedness, voting rights and board representation of the respective parties in determining if the Company is the primary beneficiary. The Company also considers all parties that have direct or implicit variable interests when determining whether it is the primary beneficiary. In accordance with ASC 810, management’s assessment of whether the Company is the primary beneficiary of a VIE is performed continuously.

As of December 31, 2019, the Company had unconsolidated VIE-related current assets and liabilities of $1.5 million and $1.4 million, respectively, included in the Company’s Consolidated Balance Sheet. As of December 31, 2018, the Company had unconsolidated VIE-related current assets and liabilities of $4.0 million and $3.8 million, respectively, included in the Company’s Consolidated Balance Sheet. The Company’s maximum exposure to loss as a result of its investments in unconsolidated VIEs is typically limited to the aggregate of the carrying value of the investment and future funding commitments. There were no future funding requirements for the unconsolidated VIEs as of December 31, 2019.

As of December 31, 2019, the Company’s Consolidated Balance Sheet included current and noncurrent assets of $365.0 million and $52.0 million, respectively, as well as current liabilities of $556.1 million related to the operations of its consolidated VIEs. As of December 31, 2018, the Company’s Consolidated Balance Sheet included current and noncurrent assets of $173.9 million and $51.5 million, respectively, as well as current liabilities of $319.9 million related to the operations of its consolidated VIEs.

Below is a discussion of some of the Company’s more significant or unique VIEs.

The Company established a joint venture to construct the Purple Line Extension Section 2 (Tunnels and Stations) and Section 3 (Stations) mass-transit projects in Los Angeles, California with a combined value of approximately $2.8 billion. The Company has a 75% interest in the joint venture with the remaining 25% held by O&G Industries, Inc. (“O&G”). The joint venture was initially financed with contributions from the partners and, per the terms of the joint venture agreement, the partners may be required to provide additional capital contributions in the future. The Company has determined that this joint venture is a VIE for which the Company is the primary beneficiary.

The Company also established a joint venture with Parsons Corporation (“Parsons”) to construct the Newark Liberty International Airport Terminal One project, a $1.4 billion transportation infrastructure project in Newark, New Jersey. The Company has an 80% interest in the joint venture with the remaining 20% held by Parsons. The joint venture was initially financed with contributions from the partners and, per the terms of the joint venture agreement, the partners may be required to provide additional capital contributions in the future. The Company has determined that this joint venture is a VIE for which the Company is the primary beneficiary.