Receivables, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Affirmative Claim Recovery Estimate	$ 21,600	$ 12,300	$ 7,800
Total Gross Receivables	627,398	419,918	513,233
Allowance for Accounts, Notes, Loans and Financing Receivable, Current	317	573	481
Receivables, net	627,081	419,345	512,752
Back charges claims	300	300	9,300
Construction Contract [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	558,066	373,038	444,705
Completed and in Progress [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	469,416	288,160	347,320
Retentions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	88,650	84,878	97,385
Construction Material Sales [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	58,920	29,357	50,768
Other Business Products and Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Gross Receivables	$ 10,412	$ 17,523	$ 17,760