Property and Equipment - Cost of Property and Equipment and related Accumulated Depreciation, Depletion and Amortization (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 125,429		$ 126,276
Less accumulated depreciation, depletion and amortization	(97,685)		(96,914)
Property and equipment, net	27,744		29,362
Total depreciation, depletion and amortization	$ 2,412	$ 3,969
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	20 years
Tractors and trailers
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 86,492		88,065
Tractors and trailers | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Tractors and trailers | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	6 years
Field equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 18,827		18,490
Field equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	2 years
Field equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 15,728		15,727
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	39 years
Office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,831		1,929
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
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,790		1,790
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	761		275
Assets held under capital leases
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,800		1,800
Less accumulated depreciation, depletion and amortization	(200)		$ (100)
Total depreciation, depletion and amortization	90	0
Assets not held under capital leases
Property, Plant and Equipment [Line Items]
Total depreciation, depletion and amortization	$ 2,322	$ 3,969