Derivative Instruments and Fair Value Measurements - Narrative (Details) - Commodity Contract	9 Months Ended	12 Months Ended
	Sep. 30, 2021 barrel_of_oil_per_day contract	Dec. 31, 2020 barrel_of_oil_per_day contract
Derivative Instruments, Gain (Loss) [Line Items]
Number of contracts held | contract	9	6
Number of contracts held, fair value | contract		3
October 2021 through December 2021
Derivative Instruments, Gain (Loss) [Line Items]
Production	740
January 2022 through December 2022
Derivative Instruments, Gain (Loss) [Line Items]
Production	194
January 2021 through December 2021
Derivative Instruments, Gain (Loss) [Line Items]
Production		192