Financial Instruments and Concentrations of Risk (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	$ 0		$ 0		$ 0		$ (17,739)
Schedule of Changes in Fair Value of Financial Assets (Liabilities) Classified as Level 3
Transfers out of Level 3	0	[1]	0	[1]	8,515	[1]
Total realized and unrealized gain (loss) included in earnings	0	[2]	0	[2]	11,041	[2]
Settlements	0		0		(1,817)
Amount of total gain or loss included in earnings for the period attributable to the change in unrealized gain or loss relating to assets and liabilities still held at the reporting date	0		0		0
Commodity Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	0		0		0		(547)
Schedule of Changes in Fair Value of Financial Assets (Liabilities) Classified as Level 3
Transfers out of Level 3	0	[1]	0	[1]	(419)	[1]
Total realized and unrealized gain (loss) included in earnings	0	[2]	0	[2]	2,783	[2]
Settlements	0		0		(1,817)
Amount of total gain or loss included in earnings for the period attributable to the change in unrealized gain or loss relating to assets and liabilities still held at the reporting date	0		0		0
Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	0		0		0		(17,192)
Schedule of Changes in Fair Value of Financial Assets (Liabilities) Classified as Level 3
Transfers out of Level 3	0	[1]	0	[1]	8,934	[1]
Total realized and unrealized gain (loss) included in earnings	0	[2]	0	[2]	8,258	[2]
Settlements	0		0		0
Amount of total gain or loss included in earnings for the period attributable to the change in unrealized gain or loss relating to assets and liabilities still held at the reporting date	$ 0		$ 0		$ 0

[1] In these tables, transfers in and transfers out are recognized as of the beginning of the reporting period for commodity derivatives and as of the transfer date for warrants.

[2] Gains and losses related to commodity derivatives are reported in product revenue. Gains and losses related to warrants are recorded in other expense (income).