Impairment

6 Months Ended

Jun. 30, 2021

Property, Plant and Equipment [Abstract]

Impairment

Impairment

The Company assesses the need to impair its oil and gas properties during its quarterly full cost pool ceiling limitation calculation. The Company analyzes various property, plant and equipment for impairment when certain triggering events occur by comparing the carrying values of the assets to their estimated fair values. The full cost pool ceiling limitation and estimated fair values of midstream and other assets were determined in accordance with the policies discussed in Note 1, as applicable.

Calculation of the full cost ceiling test is based on, among other factors, average prices for the trailing twelve-month period determined by reference to the first-day-of-the-month index prices ("SEC Prices") as adjusted for price differentials and other contractual arrangements. The SEC Prices utilized in the calculation of proved reserves included in the full cost ceiling test at June 30, 2021 were $49.78 per barrel of oil and $2.43 per Mcf of natural gas, before price differential adjustments.

In the three and six-month periods ended June 30, 2021, we did not record a full cost ceiling limitation impairment charge.

The Company recorded a total impairment charge of $201.8 million for the three-month period ended June 30, 2020, which included a full cost ceiling limitation impairment charge of $163.8 million, and an impairment charge of $38.0 million to write down the value of the Company's office headquarters. The Company recorded a total impairment charge of $209.8 million for the six-month period ended June 30, 2020, which included a full cost ceiling limitation impairment charge of $171.8 million, and an impairment charge of $38.0 million to write down the value of the Company's office headquarters.

The June 30, 2020, asset impairment charge of $38.0 million resulted from the write down of the net carrying amount of the office headquarters building assets to their estimated fair value less estimated costs to sell the building. In May 2020, the Company entered into an agreement for the sale of its corporate headquarters building located in Oklahoma City, OK. The building sale closed on August 31, 2020. Prior to the sale of the corporate headquarters building, the Company was required to report the building at its carrying amount, as a result the building was assessed for recoverability and impairment using undiscounted cash flow measures of the consolidated Company as prescribed under ASC 360-10-35, rather than fair value as prescribed under ASC 360-10-45-9.