Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Depreciable lives of property and equipment

Automobiles and trucks	3 to 5 years
Buildings and improvements	5 to 30 years
Construction equipment	3 to 15 years
Vessels and other equipment	1 to 15 years
Office equipment	1 to 5 years

The following is a summary of property and equipment at December 31, 2017 and December 31, 2016:

	December 31, 2017			December 31, 2016
Automobiles and trucks	$	1,940		$	2,525
Building and improvements	38,062			37,269
Construction equipment	166,203			165,023
Vessels and other equipment	85,113			88,659
Office equipment	8,039			7,125
	299,357			300,601
Less: accumulated depreciation	(191,407		)	(181,293		)
Net book value of depreciable assets	107,950			119,308
Construction in progress	245			543
Land	38,083			38,231
	$	146,278		$	158,082