Derivatives - Commodity derivative contracts' collar floors terminated (Details) - January 2017 - December 2017 - Derivatives not designated as hedges - Early Contract Termination - Crude Oil	Mar. 31, 2016 bbl $ / bbl
Derivative [Line Items]
Aggregate volumes (Bbl) \| bbl	2,263,000
Floor Price (dollars per Bbl) \| $ / bbl	80

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

Name:	invest_DerivativeNonmonetaryNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant