Credit Facilities and Notes Payable (Details Textual) - USD ($) $ in Thousands			12 Months Ended
	Oct. 01, 2019	Feb. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	May 01, 2020	Feb. 29, 2020
Credit Facilities and Notes Payable (Textual)
Senior secured asset-based revolving credit facility			$ 7,000	$ 118,628
Amortization of deferred issuance costs			846	966
Paid in kind interest			2,481
One-time principal reduction payment			$ 23,708	$ 64,150
Line Of Credit [Member] | Minimum [Member]
Credit Facilities and Notes Payable (Textual)
Funded debt ratio required to be maintained			1
Debt Instrument, covenant, current ratio			1
Old Ironsides Notes [Member] | Carbon Appalachia [Member]
Credit Facilities and Notes Payable (Textual)
Bank credit facility, terms				5 years
Amount of unsecured notes issuance				$ 25,200
Interest rate (as a percent)				10.00%
Number of monthly installments			24
One-time principal reduction payment		$ 2,000
Old Ironsides Notes [Member] | Carbon Appalachia [Member] | Payment in Kind (PIK) Note [Member]
Credit Facilities and Notes Payable (Textual)
Interest rate (as a percent)			12.00%
Paid in kind interest			$ 2,500
2018 Credit Facility [Member] | Carbon Appalachia [Member]
Credit Facilities and Notes Payable (Textual)
Unamortized deferred issuance costs			519
Unamortized debt discount, term note			45
Senior secured asset-based revolving credit facility			$ 500,000
Commitment fee (as a percent)			0.50%
Origination fee (as a percent)			0.50%
Credit facility			$ 75,000
Additional borrowing capacity available			$ 5,000
Debt Instrument, covenant, ratio of debt to EBITDAX			3.5
Debt Instrument, covenant, current ratio			1.0
Credit facility-revolver outstanding			$ 69,200
Debt instrument, covenant, minimum liquidity	$ 3,000
Debt instrument, covenant, minimum liquidity, term	90 days
Amortization of deferred issuance costs			$ 260	$ 786
Revolving credit facility maturing date			Dec. 31, 2022
Cash and cash equivalents of borrowers not to exceed			$ 3,000
Debt issuance costs paid, revolver and term loan			824
Debt issuance costs paid, term loan			134
Term loan			15,000
Sublimit for letters of credit			$ 1,500
Interest rate (as a percent)			6.25%
Number of monthly installments			18
2018 Credit Facility [Member] | Carbon Appalachia [Member] | Subsequent Event [Member]
Credit Facilities and Notes Payable (Textual)
Credit facility						$ 73,000
Total future borrowing base reductions					$ 6,000
2018 Credit Facility [Member] | Carbon Appalachia [Member] | Minimum [Member] | Base rate [Member]
Credit Facilities and Notes Payable (Textual)
Spread on variable base rate (as a percent)			0.25%
2018 Credit Facility [Member] | Carbon Appalachia [Member] | Minimum [Member] | London interbank offered rate [Member]
Credit Facilities and Notes Payable (Textual)
Spread on variable base rate (as a percent)			2.75%
2018 Credit Facility [Member] | Carbon Appalachia [Member] | Maximum [Member] | Base rate [Member]
Credit Facilities and Notes Payable (Textual)
Spread on variable base rate (as a percent)			0.75%
2018 Credit Facility [Member] | Carbon Appalachia [Member] | Maximum [Member] | London interbank offered rate [Member]
Credit Facilities and Notes Payable (Textual)
Spread on variable base rate (as a percent)			3.75%