Derivative Instruments - Fair value (Details) $ in Thousands	Dec. 31, 2016 USD ($) item	Dec. 31, 2015 USD ($)
Fair value of derivative instruments
Current portion of fair value of derivative assets	$ 73,022	$ 1,009,030
Noncurrent portion of fair value of derivative assets	1,731,063	2,108,450
Total asset derivatives	1,804,085	3,117,480
Current portion of fair value of derivative liabilities	203,635
Noncurrent portion of fair value of derivative liabilities	234
Total liability derivatives	203,869
Net derivatives	$ 1,600,216	$ 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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