Investments in Affiliates (Details Textual) - USD ($) $ in Thousands				3 Months Ended		9 Months Ended
	May 01, 2018	Feb. 01, 2018	Feb. 15, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 31, 2018
Investments in Affiliates (Textual)
Other income				$ 16	$ 8	$ 35	$ 28
Aggregate sharing, percentage						53.90%
Total equity method income						$ 6,511	$ (315)
Yorktown [Member] | California Warrant [Member]
Investments in Affiliates (Textual)
Warrant exercised shares		11,000
Aggregate sharing, percentage		56.40%
Carbon California [Member]
Investments in Affiliates (Textual)
Voting and profits interests, percentage	53.90%	17.81%				46.10%
Business acquisitions, description			(i) issued and sold Class A Units to Yorktown and Prudential for an aggregate cash consideration of $22.0 million, (ii) entered into a Note Purchase Agreement (the "Note Purchase Agreement") with Prudential Legacy Insurance Company of New Jersey and Prudential Insurance Company of America for the issuance and sale of up to $25.0 million of Senior Secured Revolving Notes (the "Senior Revolving Notes") due February 15, 2022 and (iii) entered into a Securities Purchase Agreement (the "Securities Purchase Agreement") with Prudential for the issuance and sale of $10.0 million of Senior Subordinated Notes (the "Subordinated Notes") due February 15, 2024. We are not a guarantor of the Senior Revolving Notes or the Subordinate Notes.
Percentage of interest								17.80%
Unsecured notes	$ 3,000
Unsecured notes due date	Feb. 15, 2024
Bearing interest of per annum	12.00%
Subordinated notes	Class A Units, representing an approximately 2% additional sharing percentage, for the issuance of the Carbon California 2018 Subordinated Notes. Carbon California valued this unit issuance based on the relative fair value by valuing the units at $1,000 per unit and aggregating the amount with the outstanding Carbon California 2018 Subordinated Notes of $3.0 million. The Company then allocated the non-cash value of the units of approximately $490,000, which was recorded as a discount to the Carbon California 2018 Subordinated Notes. As of September 30, 2018, Carbon California had an outstanding discount of $454,000 associated with these notes.
Borrowing base amount				41,000		$ 41,000
Borrowing base outstanding amount				$ 38,500		$ 38,500
Carbon California [Member] | California Warrant [Member]
Investments in Affiliates (Textual)
Voting and profits interests, percentage		56.40%
Carbon California [Member] | Note Purchase Agreement and the Securities Purchase Agreement [Member]
Investments in Affiliates (Textual)
Business acquisitions, description			(i) Senior Revolving Notes in the principal amount of $10.0 million and (ii) Subordinated Notes in the original principal amount of $10.0 million.
Carbon California [Member] | Yorktown [Member]
Investments in Affiliates (Textual)
Voting and profits interests, percentage		38.59%
Carbon California [Member] | Prudential [Member]
Investments in Affiliates (Textual)
Voting and profits interests, percentage		43.59%