Fair Value Measurements Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of Credit Facility, Fair Value of Amount Outstanding	$ 46,000		$ 46,000
Line of Credit Facility, Amount Outstanding	46,000		46,000		$ 66,100
Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Notional Amount	1,540		1,540		3,080
Gain (Losses) as a result of changes in the fair value of the contracts	91	$ (244)	34	$ (454)
Letters of Credit Outstanding as Collateral Associated with Commodity Hedges	1,100		1,100
Senior Secured Notes Due in 2016 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes, Fair Value Disclosure	4,116		4,116		160,662
Senior Notes, Carrying Value					210,000
Carrying value of senior secured notes	5,481		5,481		6,681
Senior Secured Notes Due in 2018 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes, Fair Value Disclosure	152,992		152,992
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	6,705		6,705
Carrying value of convertible debt	$ 22,323		$ 22,323		$ 0