Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 161,133	$ 153,015
Less accumulated depreciation	(109,134)	(98,609)
Property and equipment, net	51,999	54,406
Construction equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	126,082	118,868
Transportation equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	18,548	17,511
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	9,770	9,577
Office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,711	3,339
Leasehold Improvement
Property, Plant and Equipment [Line Items]
Property and equipment, gross	914	914
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	388	258
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,720	2,348
Water rights
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 0	$ 200

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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