Debt and Credit Facility	6 Months Ended
Jun. 30, 2016
Debt Disclosure [Abstract]
Debt and Credit Facility	Debt and Credit Facility Senior Notes 5.875% Senior Notes. In May 2016, we issued $375.0 million principal amount of 5.875% unsecured senior notes due May 15, 2024 ("5.875% Senior Notes") at 100% of the principal amount. The unamortized amount of debt issuance costs as of June 30, 2016 was $6.8 million. Interest expense, including amortization of debt issuance costs, relating to the 5.875% Senior Notes was $3.1 million for the quarter and six months ended June 30, 2016. A portion of the interest relating to the 5.875% Senior Notes was capitalized as construction in progress. The effective interest rate of the 5.875% Senior Notes is approximately 6.1% per annum, taking into account the amortization of debt issuance costs. The 5.875% Senior Notes are unsecured obligations and are guaranteed by certain of our domestic subsidiaries that own virtually all of our operating assets and through which we conduct the vast majority of our business. See Note 15 for condensed guarantor and non-guarantor financial information. The indenture governing the 5.875% Senior Notes places limitations on our and certain of our subsidiaries' ability to, among other things, incur liens, consolidate, merge or sell all or substantially all of our and certain of our subsidiaries' assets, incur or guarantee additional indebtedness, enter into transactions with affiliates and to make "restricted payments" (as defined in the indenture to include certain loans, investments, dividend payments, share repurchases and prepayments, redemptions or repurchases of certain indebtedness). Certain types and amounts of restricted payments are allowed by various provisions of the indenture. In particular, the indenture provisions permit us to make restricted payments in any amount if, after giving effect to such restricted payments, our "consolidated net indebtedness" as a ratio of "EBITDA" (each term as defined in the indenture) is less than 2.75:1.00. We may redeem the 5.875% Senior Notes at our option in whole or part at any time on or after May 15, 2019 at a redemption price of 104.406% of the principal amount, declining to 102.938%, 101.469% and 100% of the principal amount on or after May 15, 2020, May 15, 2021 and May 15, 2022, respectively, in each case plus any accrued and unpaid interest. At any time prior to May 15, 2019, we may also redeem some or all of the 5.875% Senior Notes at a redemption price equal to 100% of the principal amount, together with any accrued and unpaid interest, plus a "make-whole premium." Holders of the 5.875% Senior Notes have the right to require us to repurchase the 5.875% Senior Notes at a price equal to 101% of the principal amount plus any accrued and unpaid interest following a change of control. A change of control includes: (i) certain ownership changes; (ii) certain recapitalizations, mergers and dispositions; (iii) certain changes in the composition of our Board of Directors; and (iv) shareholders' approval of any plan or proposal for the liquidation or dissolution of us. We may also be required to offer to repurchase the 5.875% Senior Notes at 100% of the principal amount, plus any accrued and unpaid interest, with the proceeds of certain asset sales. In connection with the issuance of the 5.875% Senior Notes, we expect to have an exchange offer registration statement declared effective by the Securities and Exchange Commission on or prior to 240 days after the 5.875% Senior Notes were issued. If we fail to comply with the 240 day timeline, we may be required to pay additional interest. The fair value of the outstanding 5.875% Senior Notes at June 30, 2016 was approximately $383.4 million. See Note 9 for information relating to the estimated fair value of the 5.875% Senior Notes. 8.25% Senior Notes. In May 2012, we issued $225.0 million principal amount of 8.25% unsecured senior notes due June 1, 2020 ("8.25% Senior Notes"). During 2015, we repurchased $27.2 million aggregate principal amount of our 8.25% Senior Notes for 107.5% of the principal amount, and on June 1, 2016 we redeemed in full the remaining $197.8 million principal balance of our 8.25% Senior Notes at a redemption price of 104.125% of the principal amount. Upon the redemption of the 8.25% Senior Notes, our cash outflow for principal, redemption premium and accrued interest totaled $214.2 million. The $8.2 million redemption premium and $2.9 million write-off of unamortized debt issuance costs were included in Other (expense) income, net on our Statements of Consolidated Income (Loss) (see Note 13 for details). Interest expense, including amortization of debt issuance costs, relating to the 8.25% Senior Notes was $2.8 million and $4.9 million for the quarters ended June 30, 2016 and June 30, 2015, respectively, and $7.1 million and $9.7 million for the six months ended June 30, 2016 and June 30, 2015, respectively. A portion of the interest relating to the 8.25% Senior Notes was capitalized as construction in progress. The fair value of the outstanding 8.25% Senior Notes at December 31, 2015 was approximately $207.3 million. See Note 9 for information relating to the estimated fair value of the 8.25% Senior Notes. Revolving Credit Facility Our credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, and the other financial institutions party thereto ("Revolving Credit Facility") provides us with a $300.0 million funding commitment through December 2020. We had $287.6 million of borrowing availability under the Revolving Credit Facility at June 30, 2016, based on the borrowing base determination then in effect. At June 30, 2016, there were no borrowings under the Revolving Credit Facility and $7.3 million was being used to support outstanding letters of credit, leaving $280.3 million of net borrowing availability. The interest rate applicable to any overnight borrowings under the Revolving Credit Facility would have been 3.75% at June 30, 2016.

Debt and Credit Facility

Senior Notes

5.875% Senior Notes. In May 2016, we issued $375.0 million principal amount of 5.875% unsecured senior notes due May 15, 2024 ("5.875% Senior Notes") at 100% of the principal amount. The unamortized amount of debt issuance costs as of June 30, 2016 was $6.8 million. Interest expense, including amortization of debt issuance costs, relating to the 5.875% Senior Notes was $3.1 million for the quarter and six months ended June 30, 2016. A portion of the interest relating to the 5.875% Senior Notes was capitalized as construction in progress. The effective interest rate of the 5.875% Senior Notes is approximately 6.1% per annum, taking into account the amortization of debt issuance costs.

The 5.875% Senior Notes are unsecured obligations and are guaranteed by certain of our domestic subsidiaries that own virtually all of our operating assets and through which we conduct the vast majority of our business. See Note 15 for condensed guarantor and non-guarantor financial information.

The indenture governing the 5.875% Senior Notes places limitations on our and certain of our subsidiaries' ability to, among other things, incur liens, consolidate, merge or sell all or substantially all of our and certain of our subsidiaries' assets, incur or guarantee additional indebtedness, enter into transactions with affiliates and to make "restricted payments" (as defined in the indenture to include certain loans, investments, dividend payments, share repurchases and prepayments, redemptions or repurchases of certain indebtedness). Certain types and amounts of restricted payments are allowed by various provisions of the indenture. In particular, the indenture provisions permit us to make restricted payments in any amount if, after giving effect to such restricted payments, our "consolidated net indebtedness" as a ratio of "EBITDA" (each term as defined in the indenture) is less than 2.75:1.00.

We may redeem the 5.875% Senior Notes at our option in whole or part at any time on or after May 15, 2019 at a redemption price of 104.406% of the principal amount, declining to 102.938%, 101.469% and 100% of the principal amount on or after May 15, 2020, May 15, 2021 and May 15, 2022, respectively, in each case plus any accrued and unpaid interest. At any time prior to May 15, 2019, we may also redeem some or all of the 5.875% Senior Notes at a redemption price equal to 100% of the principal amount, together with any accrued and unpaid interest, plus a "make-whole premium."

Holders of the 5.875% Senior Notes have the right to require us to repurchase the 5.875% Senior Notes at a price equal to 101% of the principal amount plus any accrued and unpaid interest following a change of control. A change of control includes: (i) certain ownership changes; (ii) certain recapitalizations, mergers and dispositions; (iii) certain changes in the composition of our Board of Directors; and (iv) shareholders' approval of any plan or proposal for the liquidation or dissolution of us. We may also be required to offer to repurchase the 5.875% Senior Notes at 100% of the principal amount, plus any accrued and unpaid interest, with the proceeds of certain asset sales.

In connection with the issuance of the 5.875% Senior Notes, we expect to have an exchange offer registration statement declared effective by the Securities and Exchange Commission on or prior to 240 days after the 5.875% Senior Notes were issued. If we fail to comply with the 240 day timeline, we may be required to pay additional interest.

The fair value of the outstanding 5.875% Senior Notes at June 30, 2016 was approximately $383.4 million. See Note 9 for information relating to the estimated fair value of the 5.875% Senior Notes.

8.25% Senior Notes. In May 2012, we issued $225.0 million principal amount of 8.25% unsecured senior notes due June 1, 2020 ("8.25% Senior Notes"). During 2015, we repurchased $27.2 million aggregate principal amount of our 8.25% Senior Notes for 107.5% of the principal amount, and on June 1, 2016 we redeemed in full the remaining $197.8 million principal balance of our 8.25% Senior Notes at a redemption price of 104.125% of the principal amount. Upon the redemption of the 8.25% Senior Notes, our cash outflow for principal, redemption premium and accrued interest totaled $214.2 million. The $8.2 million redemption premium and $2.9 million write-off of unamortized debt issuance costs were included in Other (expense) income, net on our Statements of Consolidated Income (Loss) (see Note 13 for details). Interest expense, including amortization of debt issuance costs, relating to the 8.25% Senior Notes was $2.8 million and $4.9 million for the quarters ended June 30, 2016 and June 30, 2015, respectively, and $7.1 million and $9.7 million for the six months ended June 30, 2016 and June 30, 2015, respectively. A portion of the interest relating to the 8.25% Senior Notes was capitalized as construction in progress.

The fair value of the outstanding 8.25% Senior Notes at December 31, 2015 was approximately $207.3 million. See Note 9 for information relating to the estimated fair value of the 8.25% Senior Notes.

Revolving Credit Facility

Our credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, and the other financial institutions party thereto ("Revolving Credit Facility") provides us with a $300.0 million funding commitment through December 2020. We had $287.6 million of borrowing availability under the Revolving Credit Facility at June 30, 2016, based on the borrowing base determination then in effect. At June 30, 2016, there were no borrowings under the Revolving Credit Facility and $7.3 million was being used to support outstanding letters of credit, leaving $280.3 million of net borrowing availability. The interest rate applicable to any overnight borrowings under the Revolving Credit Facility would have been 3.75% at June 30, 2016.