Derivative Instruments and Fair Value Measurements - Narrative (Details) - Commodity Contract	3 Months Ended	12 Months Ended
	Mar. 31, 2018 barrel_of_oil_per_day contract	Dec. 31, 2017 barrel_of_oil_per_day contract
Derivative Instruments, Gain (Loss) [Line Items]
Number of contracts held | contract	20	20
Reported Value Measurement
Derivative Instruments, Gain (Loss) [Line Items]
Number of contracts held | contract	2	4
January 2018
Derivative Instruments, Gain (Loss) [Line Items]
Production		452
February through May 2018
Derivative Instruments, Gain (Loss) [Line Items]
Production		322
April through May 2018
Derivative Instruments, Gain (Loss) [Line Items]
Production	322
June 2018
Derivative Instruments, Gain (Loss) [Line Items]
Production	258	258
July 2018
Derivative Instruments, Gain (Loss) [Line Items]
Production	646	646
August through September 2018
Derivative Instruments, Gain (Loss) [Line Items]
Production	322	322
October through December 2018
Derivative Instruments, Gain (Loss) [Line Items]
Production	258	258
January through March 2019
Derivative Instruments, Gain (Loss) [Line Items]
Production	322