Property and Equipment (Details) (USD $)	3 Months Ended		9 Months Ended																			1 Months Ended	9 Months Ended	1 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 Land [Member]	Dec. 31, 2011 Land [Member]	Sep. 30, 2012 Depreciable Assets [Member]	Dec. 31, 2011 Depreciable Assets [Member]	Sep. 30, 2012 Building and Improvements [Member]	Dec. 31, 2011 Building and Improvements [Member]	Sep. 30, 2012 Automobiles and Trucks [Member]	Dec. 31, 2011 Automobiles and Trucks [Member]	Sep. 30, 2012 Construction Equipment [Member]	Dec. 31, 2011 Construction Equipment [Member]	Sep. 30, 2012 Dredges and Dredging Equipment [Member]	Dec. 31, 2011 Dredges and Dredging Equipment [Member]	Sep. 30, 2012 Office Equipment [Member]	Dec. 31, 2011 Office Equipment [Member]	Sep. 30, 2012 Construction in Progress [Member]	Dec. 31, 2011 Construction in Progress [Member]	Jan. 31, 2012 Acquisition of Tampa Property From Lazarra [Member] buildings	Sep. 30, 2012 Acquisition of Tampa Property From Lazarra [Member]	Jan. 31, 2012 Acquisition of Tampa Property From Lazarra [Member] Land and Building [Member] acre	Sep. 30, 2012 Maximum [Member] Acquisition of Tampa Property From Lazarra [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross						$ 14,793,000	$ 9,354,000	$ 261,539,000	$ 247,538,000	$ 21,798,000	$ 13,520,000	$ 1,591,000	$ 1,541,000	$ 135,703,000	$ 132,317,000	$ 98,379,000	$ 96,278,000	$ 4,068,000	$ 3,882,000	$ 10,246,000	$ 8,655,000
Less: accumulated depreciation								(134,358,000)	(119,440,000)
Property and equipment, net	152,220,000		152,220,000		146,107,000			127,181,000	128,098,000
Depreciation expense	5,300,000	5,600,000	16,000,000	16,700,000
Area of land purchased, including buildings and improvements																								18
Purchase price of land, buildings and improvements																								13,700,000
Commitment to make dock improvements, amount																						279,700
Construction commencement, days after closing																									90 days
Lease of land, term																							20 years
Lease payments to be made in advance, due in next 12 months																						$ 250,000
Leaseback to seller, number of buildings leased																						3
Leaseback to seller, maximum period																									24 months
Rent abatement term																							12 months