Legal Matters	6 Months Ended
Jun. 30, 2017
Loss Contingency [Abstract]
Legal matters	NOTE 8 – LEGAL MATTERS O’Reilly is currently involved in litigation incidental to the ordinary conduct of the Company’s business. The Company accrues for litigation losses in instances where a material adverse outcome is probable and the Company is able to reasonably estimate the probable loss. The Company accrues for an estimate of material legal costs to be incurred in pending litigation matters. Although the Company cannot ascertain the amount of liability that it may incur from any of these matters, it does not currently believe that, in the aggregate, these matters, taking into account applicable insurance and accruals, will have a material adverse effect on its consolidated financial position, results of operations or cash flows in a particular quarter or annual period. As previously reported, on June 18, 2015, a jury in Greene County, Missouri, returned an unfavorable verdict in a litigated contract dispute in the matter Meridian Creative Alliance vs. O’Reilly Automotive Stores, Inc. et. al. in the amount of $12.5 million. The Company has vigorously challenged the verdict in the Court of Appeals and on March 24, 2017, the Court of Appeals reversed and affirmed the verdict in part and remanded to the trial court the cause of action that resulted in the $12.5 million verdict. On April 10, 2017, Meridian Creative Alliance (“Meridian”) filed a motion for rehearing in the Court of Appeals or, in the alternative, to transfer the case to the Missouri Supreme Court. On April 17, 2017, the Court of Appeals denied Meridian’s motion. On May 2, 2017, Meridian filed an application with the Missouri Supreme Court to accept transfer of the case, which was refused on June 27, 2017. The matter was remanded to the trial court by the Court of Appeals the following day to the Circuit Court of Greene Country, Missouri. The Company will continue to vigorously defend the matter. As of June 30, 2017, the Company had accrued $18.6 million with respect to this matter.

NOTE 8 – LEGAL MATTERS

O’Reilly is currently involved in litigation incidental to the ordinary conduct of the Company’s business. The Company accrues for litigation losses in instances where a material adverse outcome is probable and the Company is able to reasonably estimate the probable loss. The Company accrues for an estimate of material legal costs to be incurred in pending litigation matters. Although the Company cannot ascertain the amount of liability that it may incur from any of these matters, it does not currently believe that, in the aggregate, these matters, taking into account applicable insurance and accruals, will have a material adverse effect on its consolidated financial position, results of operations or cash flows in a particular quarter or annual period.

As previously reported, on June 18, 2015, a jury in Greene County, Missouri, returned an unfavorable verdict in a litigated contract dispute in the matter Meridian Creative Alliance vs. O’Reilly Automotive Stores, Inc. et. al. in the amount of $12.5 million. The Company has vigorously challenged the verdict in the Court of Appeals and on March 24, 2017, the Court of Appeals reversed and affirmed the verdict in part and remanded to the trial court the cause of action that resulted in the $12.5 million verdict. On April 10, 2017, Meridian Creative Alliance (“Meridian”) filed a motion for rehearing in the Court of Appeals or, in the alternative, to transfer the case to the Missouri Supreme Court. On April 17, 2017, the Court of Appeals denied Meridian’s motion. On May 2, 2017, Meridian filed an application with the Missouri Supreme Court to accept transfer of the case, which was refused on June 27, 2017. The matter was remanded to the trial court by the Court of Appeals the following day to the Circuit Court of Greene Country, Missouri. The Company will continue to vigorously defend the matter. As of June 30, 2017, the Company had accrued $18.6 million with respect to this matter.