Note 3 - Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property and equipment, gross	$ 69,023	$ 69,048
Accumulated depreciation	(37,314)	(35,991)
Property and equipment, net	31,709	33,057
Vehicles [Member]
Property and equipment, gross	59,586	59,535
Water Transfer Equipment [Member]
Property and equipment, gross	5,140	4,952
Property, Plant and Equipment, Other Types [Member]
Property and equipment, gross	1,019	961
Building and Building Improvements [Member]
Property and equipment, gross	2,899	2,822
Land [Member]
Property and equipment, gross	379	378
Disposal Wells [Member]
Property and equipment, gross		$ 400

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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