Property and Equipment (Tables)

6 Months Ended

Jun. 30, 2018

Property, Plant and Equipment [Abstract]

The historical costs of our property and equipment and related accumulated depreciation balances were as follows at the dates indicated (in thousands):


	Estimated
	Useful Life	June 30,		December 31,
	in Years	2018		2017

Tractors and trailers ⁽¹⁾	5 – 6	$	83,686	$	88,065
Field equipment	2 – 5	19,811		18,490
Buildings	5 – 39	15,727		15,727
Office equipment	2 – 5	1,808		1,929
Land		1,790		1,790
Construction in progress		960		275
Total		123,782		126,276
Less accumulated depreciation		(96,478)		(96,914)
Property and equipment, net		$	27,304	$	29,362

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(1) Amounts include assets held under capital leases for certain tractors in our marketing segment. Gross property and equipment associated with assets held under capital leases were $1.8 million and $1.8 million at June 30, 2018 and December 31, 2017, respectively. Accumulated amortization associated with assets held under capital leases were $0.3 million and $0.1 million at June 30, 2018 and December 31, 2017, respectively (see Note 12 for further information).

Components of depreciation, depletion and amortization expense were as follows for the periods indicated (in thousands):


	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2018		2017		2018		2017
Depreciation, depletion and amortization,
excluding amounts under capital leases	$	2,171	$	3,563	$	4,493	$	7,532
Amortization of property and equipment
under capital leases	91		—		181		—
Total depreciation, depletion and amortization	$	2,262	$	3,563	$	4,674	$	7,532