Three Months Ended December 31, 2018 March 31, 2019 June 30, 2019 September 30, 2019 Net income $51,778 $69,805 $36,133 $34,397 Depreciation and amortization $24,709 $33,117 $35,482 $37,653 Interest expense $1,917 $1,903 $2,026 $1,749 Income tax expense $15,258 $21,892 $10,272 $12,340 Loss on disposal of assets $16,158 $19,228 $31,198 $31,153 Stock-based compensation $1,650 $1,829 $2,840 $577 Other expense and legal settlement $525 $187 $276 $75 Other general and administrative expenses - - $6,540 $10,786 Deferred IPO bonus expense $630 $2,314 $1,795 $3,165 Adjusted EBITDA $112,625 $150,275 $126,562 $131,895 Adjusted EBITDA Reconciliation (Non-gaap) Reconciliation of Net Income to Adjusted EBITDA ($ in Thousands) Adjusted EBITDA is not a financial measure presented in accordance with GAAP. We believe that the presentation of this non-GAAP financial measure provides useful information to investors in assessing our financial condition and results of operations. Net income is the GAAP measure most directly comparable to Adjusted EBITDA. Non-GAAP financial measures should not be considered as alternatives to the most directly comparable GAAP financial measure. Non-GAAP financial measures have important limitations as analytical tools because they exclude some, but not all, items that affect the most directly comparable GAAP financial measures. You should not consider Adjusted EBITDA in isolation or as a substitute for an analysis of our results as reported under GAAP. Because Adjusted EBITDA may be defined differently by other companies in our industry, our definitions of this non-GAAP financial measure may not be comparable to similarly titled measures of other companies, thereby diminishing their utility.
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