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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Derivative Financial Instruments (Narrative) (Details) - Commodity contract - Futures - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Other current assets
Commodity contract commitments
Fair value of derivatives including required margin deposits	$ 1,700		$ 1,700		$ 3,400
Designated as hedging instrument
Gains or losses on derivative instruments, statement of income
Ineffectiveness - amount of gain (loss) recognized in income on related hedged items	(84)	$ (191)	(175)	$ (64)
Gain (loss) excluded from hedge effectiveness testing	$ (60)	$ (1,200)	$ (125)	$ (1,200)