Receivables, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Affirmative Claim Recovery Estimate	$ 10,800	$ 12,300	$ 8,100
Total Gross Receivables	484,655	419,918	431,604
Allowance for Accounts, Notes, Loans and Financing Receivable, Current	410	573	477
Receivables, net	484,245	419,345	431,127
Back charges claims		300	10,500
Construction Contract [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	419,598	373,038	362,100
Completed and in Progress [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	343,707	288,160	266,685
Retentions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	75,891	84,878	95,415
Construction Material Sales [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	54,165	29,357	54,277
Other Business Products and Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	$ 10,892	$ 17,523	$ 15,227