Derivative Financial Instruments - Summary of Open Position for the Commodity Derivative Instruments (Parenthetical) (Details)	Jun. 30, 2015 MBbls $ / MBbls	Mar. 31, 2015 MBbls
Derivative [Line Items]
Notional	0	4,305
Basis Swap Contracts | Midland-Cushing Index
Derivative [Line Items]
Notional	2,880
Basis Swap Contracts | Minimum | Midland-Cushing Index
Derivative [Line Items]
Average index price per MBbl | $ / MBbls	1.35
Basis Swap Contracts | Maximum | Midland-Cushing Index
Derivative [Line Items]
Average index price per MBbl | $ / MBbls	1.70