Summary of Significant Accounting Principles (Tables)

3 Months Ended

Mar. 31, 2016

Depreciable lives of property and equipment

Depreciation is computed using the straight-line method over the estimated useful lives of the related assets for financial statement purposes, as follows:



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 March 31, 2016 and December 31, 2015:



	March 31, 2016			December 31, 2015
Automobiles and trucks	$	2,506		$	2,749
Building and improvements	28,302			28,226
Construction equipment	162,857			159,963
Vessels and other equipment	85,133			89,485
Office equipment	6,245			6,057
	285,043			286,480
Less: accumulated depreciation	(167,143		)	(164,371		)
Net book value of depreciable assets	117,900			122,109
Construction in progress	9,880			5,649
Land	38,231			38,231
	$	166,011		$	165,989