Nature of Ops and Sign. Acctg Policies (Details Textuals 2) shares in Millions		2 Months Ended	3 Months Ended				9 Months Ended	12 Months Ended
	Sep. 30, 2020	May 31, 2018 shares	Dec. 31, 2020 USD ($)	Sep. 18, 2020 USD ($)	Jun. 30, 2020 USD ($) shares	Mar. 31, 2020 USD ($)	Sep. 18, 2020 USD ($)	Dec. 31, 2020 USD ($) $ / Barrel	Sep. 18, 2020 $ / Barrel	Dec. 31, 2019 USD ($) $ / Barrel	Dec. 31, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Oil and Gas, Average Sale Price | $ / Barrel								35.84	40.08	55.55
Ceiling test write-downs of oil and gas properties			$ 1,006,000				$ 996,658,000			$ 0	$ 0
Costs related to CO2 pipelines not placed into service			700,000					$ 700,000
Amortization of intangible assets			$ 2,700,000				1,700,000			2,400,000	2,400,000
Carrying value of long-lived assets						$ 1,300,000,000
Allowance for loan receivable											$ 16,900,000
Issued pursuant to notes conversion, shares | shares		55.2			7.4
Impairments of unevaluated costs							$ 244,900,000			$ 18,200,000
Impairment of long-lived assets				$ 0	$ 0	$ 0
Minimum
Property, Plant and Equipment [Line Items]
Useful life of intangible CO2 contracts	7 years		7 years
Maximum
Property, Plant and Equipment [Line Items]
Useful life of intangible CO2 contracts	14 years		14 years
Pipelines | Minimum
Property, Plant and Equipment [Line Items]
Useful life	20 years		20 years
Pipelines | Maximum
Property, Plant and Equipment [Line Items]
Useful life	43 years		43 years
Vehicles | Minimum
Property, Plant and Equipment [Line Items]
Useful life			1 year
Vehicles | Maximum
Property, Plant and Equipment [Line Items]
Useful life			6 years
Furniture and Fixtures | Minimum
Property, Plant and Equipment [Line Items]
Useful life			1 year
Furniture and Fixtures | Maximum
Property, Plant and Equipment [Line Items]
Useful life			6 years
Computer Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life			1 year
Computer Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life			5 years