Commitments and Contingencies (Details 2) bbl in Thousands, $ in Thousands	Dec. 31, 2015 USD ($) bbl
Fixed Price Sales [Member]
Summary Of Purchase And Sale Commitments
Sale commitments, Volume (barrels) | bbl	2,907
Sale commitments, Value | $	$ 116,329
Floating Price Sales [Member]
Summary Of Purchase And Sale Commitments
Sale commitments, Volume (barrels) | bbl	19,691
Sale commitments, Value | $	$ 709,991
Fixed Price Purchases [Member]
Summary Of Purchase And Sale Commitments
Purchase commitments, Volume (barrels) | bbl	1,976
Purchase commitments, Value | $	$ 71,709
Floating Price Purchases [Member]
Summary Of Purchase And Sale Commitments
Purchase commitments, Volume (barrels) | bbl	17,361
Purchase commitments, Value | $	$ 652,122