Property and Equipment - Cost of Property and Equipment and Related Accumulated Depreciaiton, Depletion, and Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 126,276	$ 190,648
Less accumulated depreciation, depletion and amortization	(96,914)	(144,323)
Property and equipment, net	29,362	46,325
Depreciation, depletion and amortization	$ 13,599	18,792	$ 23,717
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	20 years
Tractors and Trailers [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 88,065	89,576
Tractors and Trailers [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Tractors and Trailers [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	6 years
Oil and Gas (Successful Efforts) [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 0	62,784
Field Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 18,490	18,282
Field Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	2 years
Field Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 15,727	15,707
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	39 years
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,929	1,913
Office Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	1 year
Office Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,790	1,790
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	275	596
Assets Held under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,800
Less accumulated depreciation, depletion and amortization	(100)
Depreciation, depletion and amortization	121	0	0
Assets Not Held under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Depreciation, depletion and amortization	$ 13,478	$ 18,792	$ 23,717