Commitments and Contingencies (Commitments) (Details Textuals 1)	12 Months Ended
	Dec. 31, 2015 USD ($) MMcf / d $ / Barrel MMcf
Long-term Purchase Commitment [Line Items]
Material tax assessments	$ 0
Industrial-source CO2 [Member]
Long-term Purchase Commitment [Line Items]
Term of Long Term Purchase Commitments	16 years
Oil price assumption for obligation estimate ($/Bbl) | $ / Barrel	50
Industrial-source CO2 [Member] | Minimum [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase obligation of CO2	$ 38,000,000
Industrial-source CO2 [Member] | Maximum [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase obligation of CO2	$ 56,000,000
CO2 Volumetric Production Payments and Industrial CO2 Customers [Member]
Long-term Purchase Commitment [Line Items]
Significant supply commitment remaining volume committed (MMcf) | MMcf	121,000
Significant supply commitment yearly maximum volume required (MMcf/d) | MMcf / d	106
Term of Long Term Supply Arrangement	8 years
Helium Supply Arrangement [Member]
Long-term Purchase Commitment [Line Items]
Term of Long Term Supply Arrangement	20 years
Maximum annual payment in event of shortfall	$ 8,000,000
Maximum payment in event of shortfall	$ 46,000,000