Debt	12 Months Ended
Dec. 31, 2016
Debt Disclosure [Abstract]
Debt	Note 8—Debt 12.0% Senior Unsecured PIK Notes Due 2018 On June 26, 2013, the Company completed a private placement offering of an initial aggregate principal amount of $300 million, with an additional $100 million notes option, at the discretion of the Company, of 12% Senior Unsecured PIK notes due in 2018 (the “12.0% Senior PIK notes”). The 12.0% Senior PIK notes were issued at 96% of par and the Company received $280.7 million of net cash proceeds, after deducting the discount to initial purchasers of $12 million and offering expenses of $7.3 million. In December 2013, the Company exercised its option and issued an additional $100 million of 12.0% Senior PIK notes with the same terms, at par. The Company received $100 million net cash proceeds, as no discounts and $0.2 million of offering expenses were incurred in connection with the exercise of the option. The Company redeemed all of the outstanding balance of the 12.0% Senior PIK notes on July 13, 2015 for approximately $510.7 million, including outstanding principal balance of $437.3 million, a make-whole premium of $47.6 million, and accrued interest of $25.8 million. The make-whole premium plus unamortized discount and deferred financing costs of $11.8 million were charged to loss on early extinguishment of debt, totaling $59.4 million. The amount paid for the make-whole premium has been included as a financing activity in the consolidated statement of cash flows. Prior to the redemption of these notes, the Company amortized $1.9 million and $4.1 million of deferred financing costs and debt discount to interest expense using the effective interest method for the years ended December 31, 2015 and 2014, respectively. 8.875% Senior Unsecured Notes Due 2023 On July 6, 2015, the Company issued $550 million in aggregate principal amount of 8.875% Senior Unsecured Notes due 2023 at an issue price of 97.903% of principal amount of the notes, plus accrued and unpaid interest, if any, to Deutsche Bank Securities Inc. and other initial purchasers. In this private offering, the senior unsecured notes were sold for cash to qualified institutional buyers in the United States pursuant to Rule 144A of the Securities Act and to persons outside of the United States in compliance with Rule S under the Securities Act. Upon closing, the Company received proceeds of approximately $525.5 million, after deducting original issue discount, the initial purchasers discounts and offering expenses, of which the Company used approximately $510.7 million to finance the redemption of all of its outstanding 12.0% Senior PIK notes. The Company used the remaining proceeds to fund its capital expenditure plan and for general corporate purposes. The fair value of the senior unsecured notes at December 31, 2016 was approximately $533.1 million. During the years ended December 31, 2016 and December 31, 2015, the Company amortized $3.3 million and $1.5 million, respectively, of deferred financing costs and debt discount to interest expense using the effective interest method. The indenture governing the senior unsecured notes contains covenants that, among other things, limit the ability of the Company and its restricted subsidiaries to: (i) incur additional indebtedness, (ii) pay dividends on capital stock or redeem, repurchase or retire the Company’s capital stock or subordinated indebtedness, (iii) transfer or sell assets, (iv) make investments, (v) create certain liens, (vi) enter into agreements that restrict dividends or other payments to the Company from its restricted subsidiaries, (vii) consolidate, merge or transfer all or substantially all of the assets of the Company and its restricted subsidiaries, taken as a whole, (viii) engage in transactions with affiliates, and (ix) create unrestricted subsidiaries. These covenants are subject to a number of important exceptions and qualifications set forth in the indenture. In addition, if the senior unsecured notes achieve an investment grade rating from either Moody’s Investors Service, Inc. or Standard & Poor’s Ratings Services, and no default under the indenture has then occurred and is continuing, many of such covenants will be suspended. The indenture also contains events of default, which include, among others and subject in certain cases to grace and cure periods, nonpayment of principal or interest, failure by the Company to comply with its other obligations under the indenture, payment defaults and accelerations with respect to certain other indebtedness of the Company and its restricted subsidiaries, failure of any guarantee on the senior unsecured notes to be enforceable, and certain events of bankruptcy or insolvency. The Company was in compliance with all applicable covenants in the indenture at December 31, 2016. During the year ended December 31, 2016, the Company repurchased $39.5 million of the outstanding senior unsecured notes in open market purchases for $23.4 million. The principal of the outstanding senior unsecured notes that were repurchased less cash proceeds and unamortized debt discount and deferred financing costs were charged to gain on early extinguishment of debt, totaling $14.5 million for the year ended December 31, 2016. The Company repurchased all such senior unsecured notes with cash on hand. Revolving Credit Facility During the first quarter of 2014, the Company entered into a $500 million senior secured revolving bank credit facility (the “revolving credit facility”) that matures in 2018. Borrowings under the revolving credit facility are subject to borrowing base limitations based on the collateral value of the Company’s proved properties and commodity hedge positions and are subject to semiannual redeterminations (April and October). The revolving credit facility was amended and restated on January 12, 2015. The primary change effected by the Amendment was to add Eclipse Resources Corporation as a party to the revolving credit facility and thereby subject the Company to the representations, warranties, covenants and events of default provisions thereof. Relative to the Eclipse I’s previous credit agreement, the Credit Agreement also (i) requires financial reporting regarding, and tests financial covenants with respect to, Eclipse Resources Corporation rather than Eclipse I, (ii) increases the basket sizes under certain of the negative covenants, and (iii) includes certain other changes favorable to Eclipse I. Other terms of the Credit Agreement remain generally consistent with Eclipse I’s previous credit agreement. On February 24, 2016, the Company amended its revolving credit facility to, among other things, adjust the 10Q quarterly minimum interest coverage ratio, which is the ratio of EBITDAX to Cash Interest Expense, and to a leverage ratio of Net Debt to EBITDAX and to permit the sale of certain conventional properties. The amendment to the revolving credit facility also increases the Applicable Margin (as defined in the Credit Agreement) applicable to loans and letter of credit participation fees under the Credit Agreement by 0.5% and requires the Company to, within 60 days of the effectiveness of the amendment, execute and deliver additional mortgages on the oil and gas properties that include at least 90% of the proved reserves. At December 31, 2016, the borrowing base was $125 million and the Company had no outstanding borrowings. After giving effect to outstanding letters of credit issued by the Company totaling $34.5 million, the Company had available borrowing capacity under the revolving credit facility of $90.5 million at December 31, 2016. On February 24, 2017, the borrowing base was redetermined, which increased the borrowing base to $175 million, while extending the maturity of the credit facility to January of 2020. The Company’s available borrowing capacity under the revolving credit facility is now $140.5 million. The Company’s next scheduled borrowing base redetermination is expected to be completed by October 2017. The revolving credit facility is secured by mortgages on substantially all of the Company’s properties and guarantees from the Company’s operating subsidiaries. The revolving credit facility contains certain covenants, including restrictions on indebtedness and dividends, and requirements with respect to working capital and interest coverage ratios. Interest is payable at a variable rate based on LIBOR or the prime rate based on the Company’s election at the time of borrowing. The Company was in compliance with all applicable covenants under the revolving credit facility as of December 31, 2016. Commitment fees on the unused portion of the revolving credit facility are due quarterly at 0.05% of the unused facility based on utilization.

Note 8—Debt

12.0% Senior Unsecured PIK Notes Due 2018

On June 26, 2013, the Company completed a private placement offering of an initial aggregate principal amount of $300 million, with an additional $100 million notes option, at the discretion of the Company, of 12% Senior Unsecured PIK notes due in 2018 (the “12.0% Senior PIK notes”). The 12.0% Senior PIK notes were issued at 96% of par and the Company received $280.7 million of net cash proceeds, after deducting the discount to initial purchasers of $12 million and offering expenses of $7.3 million. In December 2013, the Company exercised its option and issued an additional $100 million of 12.0% Senior PIK notes with the same terms, at par. The Company received $100 million net cash proceeds, as no discounts and $0.2 million of offering expenses were incurred in connection with the exercise of the option.

The Company redeemed all of the outstanding balance of the 12.0% Senior PIK notes on July 13, 2015 for approximately $510.7 million, including outstanding principal balance of $437.3 million, a make-whole premium of $47.6 million, and accrued interest of $25.8 million. The make-whole premium plus unamortized discount and deferred financing costs of $11.8 million were charged to loss on early extinguishment of debt, totaling $59.4 million. The amount paid for the make-whole premium has been included as a financing activity in the consolidated statement of cash flows.

Prior to the redemption of these notes, the Company amortized $1.9 million and $4.1 million of deferred financing costs and debt discount to interest expense using the effective interest method for the years ended December 31, 2015 and 2014, respectively.

8.875% Senior Unsecured Notes Due 2023

On July 6, 2015, the Company issued $550 million in aggregate principal amount of 8.875% Senior Unsecured Notes due 2023 at an issue price of 97.903% of principal amount of the notes, plus accrued and unpaid interest, if any, to Deutsche Bank Securities Inc. and other initial purchasers. In this private offering, the senior unsecured notes were sold for cash to qualified institutional buyers in the United States pursuant to Rule 144A of the Securities Act and to persons outside of the United States in compliance with Rule S under the Securities Act. Upon closing, the Company received proceeds of approximately $525.5 million, after deducting original issue discount, the initial purchasers discounts and offering expenses, of which the Company used approximately $510.7 million to finance the redemption of all of its outstanding 12.0% Senior PIK notes. The Company used the remaining proceeds to fund its capital expenditure plan and for general corporate purposes. The fair value of the senior unsecured notes at December 31, 2016 was approximately $533.1 million.

During the years ended December 31, 2016 and December 31, 2015, the Company amortized $3.3 million and $1.5 million, respectively, of deferred financing costs and debt discount to interest expense using the effective interest method.

The indenture governing the senior unsecured notes contains covenants that, among other things, limit the ability of the Company and its restricted subsidiaries to: (i) incur additional indebtedness, (ii) pay dividends on capital stock or redeem, repurchase or retire the Company’s capital stock or subordinated indebtedness, (iii) transfer or sell assets, (iv) make investments, (v) create certain liens, (vi) enter into agreements that restrict dividends or other payments to the Company from its restricted subsidiaries, (vii) consolidate, merge or transfer all or substantially all of the assets of the Company and its restricted subsidiaries, taken as a whole, (viii) engage in transactions with affiliates, and (ix) create unrestricted subsidiaries. These covenants are subject to a number of important exceptions and qualifications set forth in the indenture. In addition, if the senior unsecured notes achieve an investment grade rating from either Moody’s Investors Service, Inc. or Standard & Poor’s Ratings Services, and no default under the indenture has then occurred and is continuing, many of such covenants will be suspended. The indenture also contains events of default, which include, among others and subject in certain cases to grace and cure periods, nonpayment of principal or interest, failure by the Company to comply with its other obligations under the indenture, payment defaults and accelerations with respect to certain other indebtedness of the Company and its restricted subsidiaries, failure of any guarantee on the senior unsecured notes to be enforceable, and certain events of bankruptcy or insolvency. The Company was in compliance with all applicable covenants in the indenture at December 31, 2016.

During the year ended December 31, 2016, the Company repurchased $39.5 million of the outstanding senior unsecured notes in open market purchases for $23.4 million. The principal of the outstanding senior unsecured notes that were repurchased less cash proceeds and unamortized debt discount and deferred financing costs were charged to gain on early extinguishment of debt, totaling $14.5 million for the year ended December 31, 2016. The Company repurchased all such senior unsecured notes with cash on hand.

Revolving Credit Facility

During the first quarter of 2014, the Company entered into a $500 million senior secured revolving bank credit facility (the “revolving credit facility”) that matures in 2018. Borrowings under the revolving credit facility are subject to borrowing base limitations based on the collateral value of the Company’s proved properties and commodity hedge positions and are subject to semiannual redeterminations (April and October).

The revolving credit facility was amended and restated on January 12, 2015. The primary change effected by the Amendment was to add Eclipse Resources Corporation as a party to the revolving credit facility and thereby subject the Company to the representations, warranties, covenants and events of default provisions thereof. Relative to the Eclipse I’s previous credit agreement, the Credit Agreement also (i) requires financial reporting regarding, and tests financial covenants with respect to, Eclipse Resources Corporation rather than Eclipse I, (ii) increases the basket sizes under certain of the negative covenants, and (iii) includes certain other changes favorable to Eclipse I. Other terms of the Credit Agreement remain generally consistent with Eclipse I’s previous credit agreement.

On February 24, 2016, the Company amended its revolving credit facility to, among other things, adjust the 10Q quarterly minimum interest coverage ratio, which is the ratio of EBITDAX to Cash Interest Expense, and to a leverage ratio of Net Debt to EBITDAX and to permit the sale of certain conventional properties. The amendment to the revolving credit facility also increases the Applicable Margin (as defined in the Credit Agreement) applicable to loans and letter of credit participation fees under the Credit Agreement by 0.5% and requires the Company to, within 60 days of the effectiveness of the amendment, execute and deliver additional mortgages on the oil and gas properties that include at least 90% of the proved reserves.

At December 31, 2016, the borrowing base was $125 million and the Company had no outstanding borrowings. After giving effect to outstanding letters of credit issued by the Company totaling $34.5 million, the Company had available borrowing capacity under the revolving credit facility of $90.5 million at December 31, 2016. On February 24, 2017, the borrowing base was redetermined, which increased the borrowing base to $175 million, while extending the maturity of the credit facility to January of 2020. The Company’s available borrowing capacity under the revolving credit facility is now $140.5 million. The Company’s next scheduled borrowing base redetermination is expected to be completed by October 2017.

The revolving credit facility is secured by mortgages on substantially all of the Company’s properties and guarantees from the Company’s operating subsidiaries. The revolving credit facility contains certain covenants, including restrictions on indebtedness and dividends, and requirements with respect to working capital and interest coverage ratios. Interest is payable at a variable rate based on LIBOR or the prime rate based on the Company’s election at the time of borrowing. The Company was in compliance with all applicable covenants under the revolving credit facility as of December 31, 2016. Commitment fees on the unused portion of the revolving credit facility are due quarterly at 0.05% of the unused facility based on utilization.