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PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property and equipment
Property and equipment	$ 878,902	$ 1,015,379
Accumulated depreciation	(528,537)	(562,986)
Property and equipment held-for-sale, net		885
Total property and equipment, net	350,365	453,278
Accumulated depreciation related to finance leases	1,100	1,600
depreciation and amortization expense
Depreciation expense from property and equipment	89,848	107,738	$ 119,114
Amortization expense from finance lease	314	916	1,314
Amortization expense from intangible assets	11,661	11,900	13,102
Accretion expense from asset retirement obligation	(151)	115	183
Total depreciation and amortization	101,672	120,669	133,713
Property and Equipment Held-for-Sale and Impairments
Net loss on disposal of property and equipment	2,405	7,950	$ (3,803)
Canadian Assets
Property and Equipment Held-for-Sale and Impairments
Net loss on disposal of property and equipment	100
Machinery and equipment
Property and equipment
Property and equipment	596,441	659,835
Buildings and leasehold improvements
Property and equipment
Property and equipment	93,236	97,426
Pipelines
Property and equipment
Property and equipment	72,458	69,327
Disposal wells
Property and equipment
Property and equipment	48,097	64,149
Vehicles and equipment
Property and equipment
Property and equipment	30,975	53,819
Land
Property and equipment
Property and equipment	13,497	16,030
Computer equipment and software
Property and equipment
Property and equipment	7,127	8,051
Office furniture and equipment
Property and equipment
Property and equipment	892	1,157
Machinery and equipment - finance lease
Property and equipment
Property and equipment	537	162
Vehicles and equipment - finance lease
Property and equipment
Property and equipment	475	1,291
Computer equipment and software - finance lease
Property and equipment
Property and equipment	356	356
Other
Property and equipment
Property and equipment		497
Construction in progress
Property and equipment
Property and equipment	$ 14,811	$ 43,279