Derivatives - Derivative Transactions Resulting in Hedged Gas Contracts Outstanding (Details) - Forecast MMBTU in Thousands, MBbls in Thousands	3 Months Ended	6 Months Ended
	Dec. 31, 2020 MMBTU $ / bbl $ / MMBtu MBbls	Dec. 31, 2021 MMBTU $ / MMBtu $ / bbl MBbls	Jun. 30, 2021 MMBTU $ / bbl $ / MMBtu MBbls
Fixed Price Oil Swaps (Brent)
Derivative [Line Items]
Hedged volume (MBbls) | MBbls	2,208	2,084	3,438
Weighted-average price ($/Bbl) | $ / bbl	59.85	46.17	45.82
Purchased Oil Calls Options (Brent)
Derivative [Line Items]
Hedged volume (MBbls) | MBbls	276	0	0
Weighted-average price ($/Bbl) | $ / bbl	65.00	0	0
Fixed Price Gas Purchase Swaps (Kern, Delivered)
Derivative [Line Items]
Hedged volume (MMBtu) | MMBTU	5,060	5,535	9,045
Weighted-average price ($/MMBtu) | $ / MMBtu	2.76	2.73	2.71
Fixed Price Gas Purchase Swaps (SoCal Citygate)
Derivative [Line Items]
Hedged volume (MMBtu) | MMBTU	155	0	0
Weighted-average price ($/MMBtu) | $ / MMBtu	3.80	0	0