Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2013

Fair Value Disclosures [Abstract]

Fair Value Assumptions

The main inputs and assumptions into the fair value model for the Convertible Notes at December 31, 2013 were as follows:

Company's stock price at the end of the period	$	14.77
Expected volatility	27.2		%
Credit spreads	7.25		%
Risk-free interest rate	1.24		%

Measurement of assets and liabilities at fair value on a recurring basis

The liabilities measured at fair value on a recurring basis were as follows:

	Level 1		Level 2		Level 3		Total
As of December 31, 2013
Derivative liability for commodity hedges	$	—	$	2,871	$	—	$	2,871
As of December 31, 2012
Derivative liability for commodity hedges	$	—	$	2,494	$	—	$	2,494