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Represents the percentage of expected costs towards the settlement that the co-defendant would pay.

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Represents the amount of total expected remediation costs.

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The amount of increase in liability.

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Amount provided by defendants in expected costs toward the settlement.

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Amount of remaining accrual balance which is to be paid to third-party contractor

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The amount of remediation expense incurred.

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Represents the number of construction projects completed by the company.

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Liability attributable to (i) billings in excess of costs under the percentage of completion contract accounting method representing the difference between contractually invoiced amounts (billings) and revenue recognized based, for example, on costs incurred to estimated total costs at period end or (ii) contractually invoiced amounts (billings) in excess of costs incurred and accumulated under the completed contract accounting method that are expected to be realized within one year or one operating cycle, whichever is longer, from the reporting date.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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Amount awarded to other party in judgment or settlement of litigation.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of receivable related to a loss contingency accrual. For example, an insurance recovery receivable.

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Amount of cash inflow from the collection of receivables related to a loss contingency.

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Amount of the obligation recognized by withdrawing from a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

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Commitments and Contingencies (Details) $ in Thousands		3 Months Ended								12 Months Ended
Commitments and Contingencies (Details) $ in Thousands	Feb. 25, 2015 USD ($)	Dec. 31, 2017 USD ($) item	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Nov. 30, 2012 USD ($)	Nov. 30, 2011 USD ($)
Commitments and contingencies
Billings in excess of costs and estimated earnings		$ 159,034				$ 112,606				$ 159,034	$ 112,606
Revenue		579,017	$ 608,311	$ 631,165	$ 561,502	601,863	$ 507,828	$ 456,811	$ 430,446	2,379,995	1,996,948	$ 1,929,415
Gross Profit		68,477	$ 70,421	$ 84,483	$ 55,053	68,616	50,129	43,285	$ 39,277	278,434	201,307	$ 219,873
Withdrawal liability recorded		$ 4,700				5,700				$ 4,700	5,700			$ 7,600	$ 7,500
Disputed Receivables.
Commitments and contingencies
Receivable recorded relating to the project							17,900
Receipts related to disputed receivable							38,000
Revenue							27,500
Gross Profit							26,700	$ 0
Construction Projects
Commitments and contingencies
Number of projects under litigation \| item		1								1
Construction Project One
Commitments and contingencies
Receivable recorded relating to the project		$ 32,900								$ 32,900
Billings in excess of costs and estimated earnings		17,900								17,900
Construction Project Two \| Disputed Receivables.
Commitments and contingencies
Receipts related to disputed receivable							38,000
Revenue							27,500
Gross Profit							$ 26,700						$ 0
JCG \| North Texas Tollway Authority v. James Construction Group, LLC
Commitments and contingencies
Settlement	$ 17,000
Expected remediation cost	22,400
Remaining accrual balance		$ 15,200								$ 15,200
Percentage of expected costs second defendant would pay		20.00%								20.00%
Percentage of expected costs Company would pay		80.00%								80.00%
Increase in liability										$ 1,900
Remediation costs										3,700
JCG \| North Texas Tollway Authority v. James Construction Group, LLC \| Maximum
Commitments and contingencies
Agreed payments by second defendant in expected remediation costs toward settlement	$ 5,400
Bonding
Commitments and contingencies
Bid and completion bonds issued and outstanding		$ 705,700				$ 680,000				$ 705,700	$ 680,000