Reporting Segments The Company principally provides electric infrastructure services to government-funded utilities, private utilities, public investor-owned utilities and co-operative utilities and services in connection with on-shore drilling of oil and natural gas wells for small to large domestic independent oil and natural gas producers. As of June 30, 2019 , the Company's revenues, income before income taxes and identifiable assets are primarily attributable to three reportable segments including infrastructure services ("Infrastructure"), pressure pumping services ("Pressure Pumping") and natural sand proppant services ("Sand"). The Company's Chief Executive Officer and Chief Financial Officer comprise the Company's Chief Operating Decision Maker function ("CODM"). Segment information is prepared on the same basis that the CODM manages the segments, evaluates the segment financial statements and makes key operating and resource utilization decisions. Segment evaluation is determined on a quantitative basis based on a function of operating income (loss), as well as a qualitative basis, such as nature of the product and service offerings and types of customers. Prior to the year ended December 31, 2018 , the Company had four reportable segments, including infrastructure services, pressure pumping services, natural sand proppant services and contract land and directional drilling services. Based on its assessment of FASB ASC 280, Segment Reporting , guidance at December 31, 2018, the Company changed its reportable segment presentation in 2018, as it determined based upon both a quantitative and qualitative basis that the contract land and directional drilling services segment is not of continuing significance for accounting reporting purposes. The Company now includes the results of the entities previously included in the contract land and directional drilling services segment in the reconciling column titled "All Other" in the tables below. The results below for the three and six months ended June 30, 2018 have been retroactively adjusted to reflect this change. During the periods presented, the infrastructure services segment provided electric utility infrastructure services to government-funded utilities, private utilities, public investor-owned utilities and co-operative utilities in Puerto Rico and the northeast, southwest and midwest portions of the United States. The pressure pumping services segment provides hydraulic fracturing and water transfer services primarily in the Utica Shale of Eastern Ohio, Marcellus Shale in Pennsylvania, Eagle Ford and Permian Basins in Texas and the mid-continent region. The sand segment mines, processes and sells sand for use in hydraulic fracturing. The sand segment primarily services the Utica Shale, Permian Basin, SCOOP, STACK and Montney Shale in British Columbia and Alberta, Canada. During the periods presented, the Company also provided contract land and directional drilling services, coil tubing services, flowback services, cementing services, acidizing services, equipment rental services, crude oil hauling services and remote accommodation services. The businesses that provide these services are distinct operating segments, which the CODM reviews independently when making key operating and resource utilization decisions. None of these operating segments meet the quantitative thresholds of a reporting segment and do not meet the aggregation criteria set forth in ASC 280 Segment Reporting. Therefore, results for these operating segments are included in the column labeled "All Other" in the tables below. Additionally, assets for corporate activities, which primarily include cash and cash equivalents, inter-segment accounts receivable, prepaid insurance and certain property and equipment, are included in the All Other column. Although Mammoth LLC, which holds these corporate assets, meets one of the quantitative thresholds of a reporting segment, it does not engage in business activities from which it may earn revenues and its results are not regularly reviewed by the Company's CODM when making key operating and resource utilization decisions. Therefore, the Company does not include it as a reportable segment. Sales from one segment to another are generally priced at estimated equivalent commercial selling prices. Total revenue and Total cost of revenue amounts included in the Eliminations column in the following tables include inter-segment transactions conducted between segments. Receivables due for sales from one segment to another and for corporate allocations to each segment are included in the Eliminations column for Total assets in the following tables. All transactions conducted between segments are eliminated in consolidation. Transactions conducted by companies within the same reporting segment are eliminated within each reporting segment. The following tables set forth certain financial information with respect to the Companys reportable segments (in thousands): Three months ended June 30, 2019 Infrastructure Pressure Pumping Sand All Other Eliminations Total Revenue from external customers $ 41,821 $ 82,973 $ 29,223 $ 27,803 $  $ 181,820 Intersegment revenues  1,668 11,170 584 (13,422 )  Total revenue 41,821 84,641 40,393 28,387 (13,422 ) 181,820 Cost of revenue, exclusive of depreciation, depletion, amortization and accretion 44,864 59,835 32,676 30,640  168,015 Intersegment cost of revenues  11,797 1,141 562 (13,500 )  Total cost of revenue 44,864 71,632 33,817 31,202 (13,500 ) 168,015 Selling, general and administrative 3,035 2,664 1,380 2,376  9,455 Depreciation, depletion, amortization and accretion 7,818 10,174 4,528 7,625  30,145 Operating (loss) income (13,896 ) 171 668 (12,816 ) 78 (25,795 ) Interest expense, net 386 452 72 641  1,551 Other (income) expense, net (4,045 ) 9 (32 ) 49  (4,019 ) (Loss) income before income taxes $ (10,237 ) $ (290 ) $ 628 $ (13,506 ) $ 78 $ (23,327 ) Three months ended June 30, 2018 Infrastructure Pressure Pumping Sand All Other Eliminations Total Revenue from external customers $ 360,250 $ 100,333 $ 37,439 $ 35,572 $  $ 533,594 Intersegment revenues  1,073 15,406 1,776 (18,255 )  Total revenue 360,250 101,406 52,845 37,348 (18,255 ) 533,594 Cost of revenue, exclusive of depreciation, depletion, amortization and accretion 210,189 61,593 35,117 32,929  339,828 Intersegment cost of revenues 754 16,174 1,019 60 (18,007 )  Total cost of revenue 210,943 77,767 36,136 32,989 (18,007 ) 339,828 Selling, general and administrative 39,786 20,822 1,787 2,732  65,127 Depreciation, depletion, amortization and accretion 4,094 13,829 3,881 8,991  30,795 Impairment of long-lived assets    187  187 Operating income (loss) 105,427 (11,012 ) 11,041 (7,551 ) (248 ) 97,657 Interest expense, net 106 341 76 436  959 Other expense, net 330 80 36 40  486 Income (loss) before income taxes $ 104,991 $ (11,433 ) $ 10,929 $ (8,027 ) $ (248 ) $ 96,212 Six months ended June 30, 2019 Infrastructure Pressure Pumping Sand All Other Eliminations Total Revenue from external customers $ 150,542 $ 173,568 $ 54,187 $ 65,661 $  $ 443,958 Intersegment revenues  3,212 24,067 1,243 (28,522 )  Total revenue 150,542 176,780 78,254 66,904 (28,522 ) 443,958 Cost of revenue, exclusive of depreciation, depletion, amortization and accretion 103,828 124,047 62,928 66,282  357,085 Intersegment cost of revenues  25,334 2,188 1,060 (28,582 )  Total cost of revenue 103,828 149,381 65,116 67,342 (28,582 ) 357,085 Selling, general and administrative 12,553 5,876 2,899 5,463  26,791 Depreciation, depletion, amortization and accretion 15,537 20,068 7,401 15,715  58,721 Operating income (loss) 18,624 1,455 2,838 (21,616 ) 60 1,361 Interest expense, net 425 649 102 898  2,074 Other (income) expense, net (28,869 ) 8 (32 ) 317  (28,576 ) Income (loss) before income taxes $ 47,068 $ 798 $ 2,768 $ (22,831 ) $ 60 $ 27,863 Six months ended June 30, 2018 Infrastructure Pressure Pumping Sand All Other Eliminations Total Revenue from external customers $ 685,709 $ 196,912 $ 73,942 $ 71,280 $  $ 1,027,843 Intersegment revenues  5,632 29,918 4,193 (39,743 )  Total revenue 685,709 202,544 103,860 75,473 (39,743 ) 1,027,843 Cost of revenue, exclusive of depreciation, depletion, amortization and accretion 404,265 128,205 68,447 65,012  665,929 Intersegment cost of revenues 2,545 31,576 5,305 327 (39,753 )  Total cost of revenue 406,810 159,781 73,752 65,339 (39,753 ) 665,929 Selling, general and administrative 71,637 23,485 3,431 5,085  103,638 Depreciation, depletion, amortization and accretion 6,501 27,815 6,197 17,190  57,703 Impairment of long-lived assets    187  187 Operating income (loss) 200,761 (8,537 ) 20,480 (12,328 ) 10 200,386 Interest expense, net 182 845 156 1,013  2,196 Other expense, net 332 92 23 67  514 Income (loss) before income taxes $ 200,247 $ (9,474 ) $ 20,301 $ (13,408 ) $ 10 $ 197,676 Infrastructure Pressure Pumping Sand All Other Eliminations Total As of June 30, 2019: Total assets $ 419,368 $ 265,244 $ 216,857 $ 147,611 $ 59,830 $ 1,108,910 Goodwill $ 3,828 $ 86,043 $ 2,684 $ 8,690 $  $ 101,245 As of December 31, 2018: Total assets $ 366,457 $ 254,278 $ 177,870 $ 122,442 $ 152,044 $ 1,073,091 Goodwill $ 3,828 $ 86,043 $ 2,684 $ 8,690 $  $ 101,245