Concentration of Risk and Enterprise Wide Disclosures Narrative (Details) - Customer concentration risk	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Trade and contract retainage receivables
Concentration Risk [Line Items]
Concentration risk, percentage			100.00%		100.00%
Contract revenues
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Private Sector Customer | Trade and contract retainage receivables
Concentration Risk [Line Items]
Concentration risk, percentage			12.90%		14.00%
Local Port Authority Customer | Contract revenues
Concentration Risk [Line Items]
Concentration risk, percentage	15.10%		11.40%
Private Customer 1 | Contract revenues
Concentration Risk [Line Items]
Concentration risk, percentage		11.50%		12.50%
Private Customer 2 | Contract revenues
Concentration Risk [Line Items]
Concentration risk, percentage		10.90%		10.70%