Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment

Schedule of property, plant and equipment at cost net of accumulated depreciation

December 31,	2016			2015
(in thousands)
Land	$	19,070		$	19,056
Buildings and leasehold improvements		142,741			142,715
Operating equipment		1,432,007			1,440,508
Computer software		22,050			19,650
Furniture and fixtures		8,056			8,043
Vehicles		469,570			480,899
Construction in progress		—			6
Gross property, plant and equipment		2,093,494			2,110,877
Less: accumulated depreciation		(1,595,508	)		(1,422,542	)
Net property, plant and equipment	$	497,986		$	688,335