Fair Value Measurements Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	May 19, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	$ 3,284		$ 3,284		$ 11,574	$ 0
Line of Credit Facility, Fair Value of Amount Outstanding	12,500		12,500
Line of Credit Facility, Amount Outstanding	12,500		12,500			66,100
Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Notional Amount	770		770			3,080
Gain (Losses) as a result of changes in the fair value of the contracts	(3)	$ (252)	31	$ (706)
Letters of Credit Outstanding as Collateral Associated with Commodity Hedges	700		700
Senior Secured Notes Due in 2016 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure						160,662
Senior Notes, Carrying Value						210,000
Carrying value of senior secured notes	0		0			6,681
Senior Secured Notes Due in 2018 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	153,901		153,901
Carrying value of senior secured notes	204,519		204,519			203,319
Convertible Notes Due in 2017 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of convertible debt	25		25			21,966
Carrying value of convertible debt	41		41			57,500
Convertible Notes Due in 2019 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of convertible debt	8,233		8,233
Carrying value of convertible debt	$ 22,323		$ 22,323			$ 0