Derivative Instruments - Fair value (Details) $ in Thousands	Sep. 30, 2016 USD ($) item	Dec. 31, 2015 USD ($)
Fair value of derivative instruments
Current portion of fair value of derivative assets	$ 417,605	$ 1,009,030
Noncurrent portion of fair value of derivative assets	2,015,090	2,108,450
Total asset derivatives	2,432,695	3,117,480
Current portion of fair value of derivative liability	3,110
Noncurrent portion of fair value of derivative liability	40
Total liability derivatives	3,150
Derivatives not designated as hedges for accounting purposes \| Net fair value of commodity derivatives
Fair value of derivative instruments
Current portion of fair value of derivative assets	417,605	1,009,030
Noncurrent portion of fair value of derivative assets	2,015,090	2,108,450
Total asset derivatives	2,432,695	3,117,480
Current portion of fair value of derivative liability	3,110
Noncurrent portion of fair value of derivative liability	40
Total liability derivatives	3,150
Net derivatives	$ 2,429,545	$ 3,117,480
Derivatives designated as hedges for accounting purposes
Fair value of derivative instruments
Number of derivative instruments held designated as hedges \| item	0

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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