Property and Equipment (Details) (USD $)	12 Months Ended																			1 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Land	Dec. 31, 2011 Land	Dec. 31, 2012 Depreciable Assets [Member]	Dec. 31, 2011 Depreciable Assets [Member]	Dec. 31, 2012 Automobiles and trucks	Dec. 31, 2011 Automobiles and trucks	Dec. 31, 2012 Building and improvements	Dec. 31, 2011 Building and improvements	Dec. 31, 2012 Construction equipment	Dec. 31, 2011 Construction equipment	Dec. 31, 2012 Dredges and dredging equipment	Dec. 31, 2011 Dredges and dredging equipment	Dec. 31, 2012 Office equipment	Dec. 31, 2011 Office equipment	Dec. 31, 2012 Construction in progress	Dec. 31, 2011 Construction in progress	Jan. 31, 2012 Acquisition of Tampa Property from Lazarra buildings	Dec. 31, 2012 Acquisition of Tampa Property from Lazarra	Jan. 31, 2012 Acquisition of Tampa Property from Lazarra Land and Building [Member] acre	Oct. 31, 2012 Purchase of the assets of West Construction	Dec. 31, 2012 Maximum Acquisition of Tampa Property from Lazarra
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross				$ 14,793,000	$ 9,354,000	$ 265,485,000	$ 247,538,000	$ 1,591,000	$ 1,541,000	$ 22,037,000	$ 13,520,000	$ 140,835,000	$ 132,317,000	$ 96,927,000	$ 96,278,000	$ 4,095,000	$ 3,882,000	$ 6,949,000	$ 8,655,000
Less: accumulated depreciation						(136,556,000)	(119,440,000)
Property and equipment, net	150,671,000	146,107,000				128,929,000	128,098,000
Depreciation expense	21,500,000	22,100,000	19,400,000
Area of land purchased, including buildings and improvements																						18
Purchase price of significant acquisitions during period																						13,700,000	9,300,000
Commitment to make dock improvements, amount																				279,700
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
Fixed assets increase due to acquisition																							4,500,000
Impairment loss on assets held-for-sale	$ 2,000,000