Derivative Commodity Instruments (Tables)

12 Months Ended

Dec. 31, 2012

Derivative Instruments and Hedges, Assets [Abstract]

Fair Values Of Derivative Instruments In Consolidated Balance Sheets

The fair values of derivative instruments in the Company's consolidated balance sheets were as follows:

	Asset Derivatives
	Balance Sheet Location	Fair Value as of December 31,
		2012		2011
Designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	$	13,032	$	—
Not designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	1,395		2,437
Total asset derivatives		$	14,427	$	2,437
	Liability Derivatives
	Balance Sheet Location	Fair Value as of December 31,
		2012		2011
Designated as hedging instruments
Commodity forward contracts	Accrued liabilities	$	399	$	3,262
Not designated as hedging instruments
Commodity forward contracts	Accrued liabilities	13,295		973
Total liability derivatives		$	13,694	$	4,235

Impact Of Derivative Instruments Designated As Fair Value Hedges

Derivatives in Fair Value    Hedging Relationships	Location of Gain (Loss) Recognized in Income on Derivative	Year Ended December 31,
		2012		2011			2010
Commodity forward contracts	Cost of sales	$	17,163	$	(4,895	)	$	—

Hedged Items in Fair Value    Hedging Relationships	Location of Gain (Loss) Recognized in Income on  Hedged Items	Year Ended December 31,
		2012			2011		2010
Firm commitment designated as the    hedged item	Cost of sales	$	(18,394	)	$	5,092	$	—

Impact Of Derivative Instruments Not Designated As Fair Value Hedges

The impact of derivative instruments that have not been designated as hedges on the Company's consolidated statements of operations were as follows:

Derivatives Not Designated as    Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivative	Year Ended December 31,
		2012			2011		2010
Commodity forward contracts	Cost of sales	$	(11,626	)	$	2,043	$	69