Note 3 - Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property and equipment, gross	$ 69,048	$ 59,765
Accumulated depreciation	(35,991)	(31,453)
Property and equipment, net	33,057	28,312
Vehicles [Member]
Property and equipment, gross	59,535	50,142
Water Transfer Equipment [Member]
Property and equipment, gross	4,952	2,425
Property, Plant and Equipment, Other Types [Member]
Property and equipment, gross	961	3,136
Building and Building Improvements [Member]
Property and equipment, gross	2,822	3,082
Land [Member]
Property and equipment, gross	378	589
Disposal Wells [Member]
Property and equipment, gross	$ 400	$ 391

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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