Derivative Instruments (Tables)

3 Months Ended

Mar. 31, 2015

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Values of Derivatives Instruments in Consolidated Balance Sheets

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

	Derivative Assets
	Balance Sheet Location	Fair Value as of
		March 31, 2015		December 31, 2014
Not designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	$	2,927	$	3,145
Commodity forward contracts	Deferred charges and    other assets, net	1,557		—
Total derivative assets		$	4,484	$	3,145

	Derivative Liabilities
	Balance Sheet Location	Fair Value as of
		March 31, 2015		December 31, 2014
Not designated as hedging instruments
Commodity forward contracts	Accrued liabilities	$	5,060	$	6,549
Commodity forward contracts	Other liabilities	1,801		3,559
Total derivative liabilities		$	6,861	$	10,108

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	Three Months Ended March 31,
		2015		2014
Commodity forward contracts	Gross profit	$	4,241	$	(611	)