Subsidiary Bankruptcy, Deconsolidation and Sale	12 Months Ended
Dec. 31, 2017
Reorganizations [Abstract]
Subsidiary Bankruptcy, Deconsolidation and Sale	Subsidiary Bankruptcy, Deconsolidation and Sale Bankruptcy Filing, Deconsolidation and Sale On April 21, 2017, AREC filed a voluntary petition in the Bankruptcy Court seeking relief under the Bankruptcy Code. AREC operated its business and managed its properties as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of the Bankruptcy Code and order of the Bankruptcy Court. As a result of AREC’s bankruptcy filing, AE ceded its authority to the Bankruptcy Court, and AE management could not carry on AREC activities in the ordinary course of business without Bankruptcy Court approval. AE managed the day-to-day operations of AREC, but did not have discretion to make significant capital or operating budgetary changes or decisions or to purchase or sell significant assets, as AREC’s material decisions were subject to review and approval by the Bankruptcy Court. For these reasons, we concluded that AE lost control of AREC, and no longer had significant influence over AREC during the pendency of the bankruptcy. Therefore, we deconsolidated AREC effective with the filing of the Chapter 11 bankruptcy in April 2017. In order to deconsolidate AREC, the carrying values of the assets and liabilities of AREC were removed from our consolidated balance sheet as of April 30, 2017, and we recorded our investment in AREC at its estimated fair value of approximately $5.0 million. We determined the fair value of our investment based upon bids we received in an auction process (see Note 1 for further discussion). We also determined that the estimated fair value of our investment in AREC was expected to be lower than its net book value immediately prior to the deconsolidation. As a result, during the second quarter of 2017, we recorded a non-cash charge of approximately $1.6 million associated with the deconsolidation of AREC, which reflected the excess of the net assets of AREC over its estimated fair value based on the expected sales transaction price of approximately $5.0 million, net of estimated transaction costs. Subsequent to the deconsolidation of AREC, we accounted for our investment in AREC using the cost method of accounting because AE did not exercise significant influence over the operations of AREC due to the Chapter 11 filing. On August 1, 2017, a hearing was held before the Bankruptcy Court seeking approval of asset purchase and sales agreements under Section 363 of the Bankruptcy Code with three unaffiliated parties to purchase AREC’s crude oil and natural gas assets for aggregate cash proceeds of approximately $5.2 million. The Bankruptcy Court approved the asset purchase and sales agreements, and we closed on the sales of these assets during the third quarter of 2017. In October 2017, AREC submitted its liquidation plan to the Bankruptcy Court for approval. In connection with the sales of these assets and submission of the liquidation plan, we recognized an additional loss of $1.9 million during the third quarter of 2017, which represents the difference between the proceeds we expect to be paid upon settlement of the bankruptcy, net of anticipated remaining closing costs identified as part of the liquidation plan, and the book value of our cost method investment. In December 2017, we received proceeds of approximately $2.8 million from AREC related to the settlement of a portion of the bankruptcy process. The bankruptcy process is expected to be completed with a confirmed plan during 2018. DIP Financing – Related Party Relationship In connection with the bankruptcy filing, AREC entered into a Debtor in Possession Credit and Security Agreement with AE (“DIP Credit Agreement”) dated as of April 25, 2017, in an aggregate amount of up to $1.25 million, of which the funds were to be used by AREC solely to fund operations through August 11, 2017. Loans under the DIP Credit Agreement accrued interest at a rate of LIBOR plus 2.0 percent per annum and were due and payable upon the earlier of (a) twelve months after the petition date, (b) the closing of the sale of substantially all of AREC’s assets, (c) the effective date of a Chapter 11 plan of reorganization of AREC, and (d) the date that the DIP loan was accelerated upon the occurrence of an event of default, as defined in the DIP Credit Agreement. AREC borrowed approximately $0.4 million under the DIP Credit Agreement, and the amount was repaid during the third quarter of 2017 with proceeds from the sales of the assets.

Subsidiary Bankruptcy, Deconsolidation and Sale

Bankruptcy Filing, Deconsolidation and Sale

On April 21, 2017, AREC filed a voluntary petition in the Bankruptcy Court seeking relief under the Bankruptcy Code. AREC operated its business and managed its properties as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of the Bankruptcy Code and order of the Bankruptcy Court. As a result of AREC’s bankruptcy filing, AE ceded its authority to the Bankruptcy Court, and AE management could not carry on AREC activities in the ordinary course of business without Bankruptcy Court approval. AE managed the day-to-day operations of AREC, but did not have discretion to make significant capital or operating budgetary changes or decisions or to purchase or sell significant assets, as AREC’s material decisions were subject to review and approval by the Bankruptcy Court. For these reasons, we concluded that AE lost control of AREC, and no longer had significant influence over AREC during the pendency of the bankruptcy. Therefore, we deconsolidated AREC effective with the filing of the Chapter 11 bankruptcy in April 2017.

In order to deconsolidate AREC, the carrying values of the assets and liabilities of AREC were removed from our consolidated balance sheet as of April 30, 2017, and we recorded our investment in AREC at its estimated fair value of approximately $5.0 million. We determined the fair value of our investment based upon bids we received in an auction process (see Note 1 for further discussion). We also determined that the estimated fair value of our investment in AREC was expected to be lower than its net book value immediately prior to the deconsolidation. As a result, during the second quarter of 2017, we recorded a non-cash charge of approximately $1.6 million associated with the deconsolidation of AREC, which reflected the excess of the net assets of AREC over its estimated fair value based on the expected sales transaction price of approximately $5.0 million, net of estimated transaction costs. Subsequent to the deconsolidation of AREC, we accounted for our investment in AREC using the cost method of accounting because AE did not exercise significant influence over the operations of AREC due to the Chapter 11 filing.

On August 1, 2017, a hearing was held before the Bankruptcy Court seeking approval of asset purchase and sales agreements under Section 363 of the Bankruptcy Code with three unaffiliated parties to purchase AREC’s crude oil and natural gas assets for aggregate cash proceeds of approximately $5.2 million. The Bankruptcy Court approved the asset purchase and sales agreements, and we closed on the sales of these assets during the third quarter of 2017.

In October 2017, AREC submitted its liquidation plan to the Bankruptcy Court for approval. In connection with the sales of these assets and submission of the liquidation plan, we recognized an additional loss of $1.9 million during the third quarter of 2017, which represents the difference between the proceeds we expect to be paid upon settlement of the bankruptcy, net of anticipated remaining closing costs identified as part of the liquidation plan, and the book value of our cost method investment. In December 2017, we received proceeds of approximately $2.8 million from AREC related to the settlement of a portion of the bankruptcy process. The bankruptcy process is expected to be completed with a confirmed plan during 2018.

DIP Financing – Related Party Relationship

In connection with the bankruptcy filing, AREC entered into a Debtor in Possession Credit and Security Agreement with AE (“DIP Credit Agreement”) dated as of April 25, 2017, in an aggregate amount of up to $1.25 million, of which the funds were to be used by AREC solely to fund operations through August 11, 2017. Loans under the DIP Credit Agreement accrued interest at a rate of LIBOR plus 2.0 percent per annum and were due and payable upon the earlier of (a) twelve months after the petition date, (b) the closing of the sale of substantially all of AREC’s assets, (c) the effective date of a Chapter 11 plan of reorganization of AREC, and (d) the date that the DIP loan was accelerated upon the occurrence of an event of default, as defined in the DIP Credit Agreement. AREC borrowed approximately $0.4 million under the DIP Credit Agreement, and the amount was repaid during the third quarter of 2017 with proceeds from the sales of the assets.