Summary of Significant Accounting Policies - Depreciable Lives of Property and Equipment (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation expense									$ 26,900	$ 23,700	$ 23,500
Net (loss) income									$ (3,620)	$ (8,060)	$ 6,877
Diluted (in dollars per share)	$ (0.23)	$ 0.17	$ (0.03)	$ (0.04)	$ 0.06	$ (0.27)	$ (0.07)	$ (0.01)	$ (0.13)	$ (0.29)	$ 0.25
Equipment improvement | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									3 years
Equipment improvement | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									7 years
Automobiles and trucks | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									3 years
Automobiles and trucks | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									5 years
Building and improvements | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									5 years
Building and improvements | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									30 years
Construction equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									3 years
Construction equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									15 years
Dredges and dredging equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									1 year
Dredges and dredging equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									15 years
Office equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									1 year
Office equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									5 years
Dry-docking capitalized costs | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									3 years
Dry-docking capitalized costs | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life									15 years