Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Our financial instruments consist of cash and cash equivalents, receivables, payables and debt instruments. We believe that the carrying values of these instruments on the accompanying consolidated balance sheets approximate their fair values. As of December 31, 2019 and 2018, we believe the carrying value of our floating-rate debt outstanding under our term loans and revolving credit facilities approximates fair value because the terms include short-term interest rates and exclude penalties for prepayment. We estimated the fair value of our floating-rate term loan and revolving credit facilities using significant other observable inputs, representative of a Level 2 fair value measurement, including terms and credit spreads for these loans. During 2019, 2018 and 2017, we wrote down certain long-lived assets to fair value. During the fourth quarter of 2019, we also recorded a goodwill impairment charge related to one of our reporting units. Our estimates of fair value required us to use significant unobservable inputs, representative of Level 3 fair value measurements, including numerous assumptions with respect to future circumstances that might directly impact each of the relevant asset groups’ operations in the future and are therefore uncertain. These assumptions with respect to future circumstances included future oil, met coal and natural gas prices, anticipated spending by our customers, the cost of capital, and industry and/or local market conditions. During the fourth quarter of 2019 and the third quarter of 2017, our estimates of fair value of corporate office space in Canada and certain undeveloped land positions in British Columbia were based on appraisals from third parties. Please see Note 2 – Summary of Significant Accounting Policies – Impairment of Long-Lived Assets and Note 2 – Summary of Significant Accounting Policies – Goodwill and Other Intangible Assets for further discussion of the significant judgments and assumptions used in calculating their fair value. During 2019 and 2018, we acquired certain assets and businesses and recorded them at fair value. Determining the fair value of assets acquired and liabilities assumed requires the exercise of significant judgment, including the amount and timing of expected future cash flows, long-term growth rates and discount rates. The cash flows employed in the valuation are based on our best estimates of future sales, earnings and cash flows after considering factors such as general market conditions, expected future customer orders, contracts with suppliers, labor costs, changes in working capital, long term business plans and recent operating performance. Please see Note 7 – Acquisitions for further information.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.