Long-Term Debt - Narrative (Details)									1 Months Ended	9 Months Ended	12 Months Ended
		Dec. 21, 2016 USD ($)	Dec. 13, 2016 USD ($)	Dec. 12, 2016	Oct. 14, 2016 USD ($)	Oct. 06, 2016 USD ($)	Apr. 21, 2016 USD ($)	Dec. 27, 2013	Dec. 31, 2015 USD ($)	Sep. 30, 2013 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Oct. 31, 2016 USD ($)	Feb. 19, 2016 USD ($)	Feb. 18, 2016 USD ($)	Jun. 04, 2015 USD ($)	Apr. 21, 2015 USD ($)	Aug. 18, 2014 USD ($)	Dec. 21, 2012 USD ($)	Oct. 17, 2012 USD ($)	Mar. 31, 2011 USD ($)
Debt Instrument [Line Items]
Long-tern debt											$ 1,621,049,000
Deferred finance costs	[1]								$ 17,883,000		27,174,000	$ 17,883,000
Unamortized original issue (discount) premium, net	[2]								(12,493,000)		0	(12,493,000)
Capitalized interest costs											9,148,000	13,580,000	$ 9,687,000
Building loans
Debt Instrument [Line Items]
Stated interest rate																						5.82%
Long-tern debt																						$ 2,400,000
Monthly interest and principal payments										$ 22,000
Debt issued	[3]								1,653,000			1,653,000
Capitalized interest costs											400,000	300,000
Revolving credit agreement
Debt Instrument [Line Items]
Debt issued	[4]								0		0	0
Construction loans
Debt Instrument [Line Items]
Debt issued	[5]								0			0
Senior notes
Debt Instrument [Line Items]
Write off of remaining premium and discount											10,800,000
Oil and gas properties
Debt Instrument [Line Items]
Capitalized interest costs											$ 8,700,000	$ 13,300,000
Nova Scotia, Amegy, KeyBank | Base Rate | Minimum
Debt Instrument [Line Items]
Stated interest rate								1.00%
Nova Scotia, Amegy, KeyBank | Base Rate | Maximum
Debt Instrument [Line Items]
Stated interest rate								2.00%
Nova Scotia, Amegy, KeyBank | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate								0.50%
Nova Scotia, Amegy, KeyBank | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate								1.00%
Nova Scotia, Amegy, KeyBank | Eurodollar | Minimum
Debt Instrument [Line Items]
Stated interest rate								2.00%
Nova Scotia, Amegy, KeyBank | Eurodollar | Maximum
Debt Instrument [Line Items]
Stated interest rate								3.00%
InterBank | Letter of credit | Construction loans
Debt Instrument [Line Items]
Maximum borrowing capacity																	$ 24,500,000
Required minimum down payment percentage											30.00%
Stated interest rate																	4.50%
Deferred finance costs											$ 100,000
Debt issued	[5]										$ 21,049,000
Amended and Restated Credit Agreement | Maximum
Debt Instrument [Line Items]
Debt covenant ratio for future EBITDAX											4.00
Amended and Restated Credit Agreement | Revolving credit agreement
Debt Instrument [Line Items]
Debt covenant ratio for EBITDAX										3.00
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank
Debt Instrument [Line Items]
Debt instrument, description of rate											LIBOR01
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank | Revolving credit agreement
Debt Instrument [Line Items]
Maximum borrowing capacity											$ 1,500,000,000
Required minimum down payment percentage			85.00%	80.00%
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank | Revolving credit agreement | Minimum
Debt Instrument [Line Items]
Borrowing base															$ 700,000,000
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank | Unsecured Debt | Revolving credit agreement
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 1,600,000,000												1,400,000,000	$ 1,200,000,000
Long-term line of credit outstanding															$ 950,000,000
Basis spread increase			0.005
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank | Letter of credit
Debt Instrument [Line Items]
Long-term line of credit outstanding											209,700,000
Future borrowings available											490,300,000
Disposition costs, maximum expenses allowed											$ 3,000,000.0
Refinanced Building Loan | Building loans
Debt Instrument [Line Items]
Stated interest rate											4.00%
Monthly interest and principal payments									$ 20,000
7.75% Senior notes 2020 | Senior notes
Debt Instrument [Line Items]
Stated interest rate									7.75%		7.75%	7.75%							7.75%
Aggregate principal amount	[6]																		$ 600,000,000.0
Conversion ratio for cash consideration						1.042
Debt repurchase, amount tendered						$ 403,500,000
Repurchased face amount					$ 196,500,000									$ 600,000,000.0
Redemption price percentage redeemed					103.875%
Debt issued	[7]								$ 600,000,000		$ 0	$ 600,000,000
6.625% Senior notes 2023 | Senior notes
Debt Instrument [Line Items]
Stated interest rate									6.625%		6.625%	6.625%						6.625%
Aggregate principal amount																		$ 350,000,000.0
Proceeds from issuance of Senior notes							$ 343,600,000
Deferred finance costs											$ 6,000,000
Debt issued	[6]								$ 350,000,000		$ 350,000,000	$ 350,000,000
6.000% Senior notes 2024 | Senior notes
Debt Instrument [Line Items]
Stated interest rate					6.00%				6.00%		6.00%	6.00%
Aggregate principal amount					$ 650,000,000.0
Proceeds from issuance of Senior notes					$ 638,900,000
Deferred finance costs											$ 10,900,000
Debt issued	[8]								$ 0		$ 650,000,000	$ 0
6.375% Senior Notes 2025 | Senior notes
Debt Instrument [Line Items]
Stated interest rate		6.375%							6.375%		6.375%	6.375%
Aggregate principal amount		$ 600,000,000
Proceeds from issuance of Senior notes		$ 590,800,000
Deferred finance costs											$ 10,100,000
Debt issued	[9]								$ 0		$ 600,000,000	$ 0
October Notes | Senior notes
Debt Instrument [Line Items]
Discount issue price, percent																					98.534%
Unamortized discount																					$ 3,700,000
Effective interest rate																					8.00%
October Notes | Wells Fargo Bank | Senior notes
Debt Instrument [Line Items]
Aggregate principal amount																					$ 250,000,000
December Notes | Senior notes
Debt Instrument [Line Items]
Effective interest rate																				7.531%
Premium issue price, percent																				101.00%
Unamortized premium																				$ 500,000
December Notes | Wells Fargo Bank | Senior notes
Debt Instrument [Line Items]
Aggregate principal amount																				$ 50,000,000
August Notes | Senior notes
Debt Instrument [Line Items]
Effective interest rate																			6.561%
Premium issue price, percent																			106.00%
Unamortized premium																			$ 18,000,000
August Notes | Wells Fargo Bank | Senior notes
Debt Instrument [Line Items]
Aggregate principal amount																			$ 300,000,000

[1] In accordance with ASU 2015-03, loan issuance cost related to the Notes have been presented as a reduction to the Notes. At December 31, 2016, total unamortized debt issuance costs were $6.0 million for the 2023 Notes, $10.9 million for the 2024 Notes, and $10.1 million for the 2025 Notes. In addition, loan commitment fee costs for the construction loan agreement described immediately below were $0.1 million at December 31, 2016.

[2] The October Notes were issued at a price of 98.534% resulting in a gross discount of $3.7 million and an effective rate of 8.000%. The December Notes were issued at a price of 101.000% resulting in a gross premium of $0.5 million and an effective rate of 7.531%. The August Notes were issued at a price of 106.000% resulting in a gross premium of $18.0 million and an effective rate of 6.561%. The 2023 Notes, 2024 Notes, and 2025 Notes were issued at par. The premium and discount was amortized using the effective interest method until the bonds were redeemed, at which point the remaining premium and discount of $10.8 million was written off and is included in loss on debt extinguishment on the consolidated statements of operations.

[3] In March 2011, the Company entered into a new building loan agreement for the office building it occupies in Oklahoma City, Oklahoma. The new loan agreement refinanced the $2.4 million outstanding under the previous building loan agreement. The new agreement matured in February 2016 and bore interest at the rate of 5.82% per annum. The new building loan required monthly interest and principal payments of approximately $22,000 and was collateralized by the Oklahoma City office building and associated land. Subsequently, the loan was refinanced with a new interest rate of 4.00% per annum. The building loan matured in December 2018 and required monthly interest and principal payments of approximately $20,000. The Company paid the balance of the loan in full in February 2016.

[4] The Company has entered into a senior secured revolving credit facility as amended, with the Bank of Nova Scotia, as the lead arranger and administrative agent and certain lenders from time to time party thereto. The credit agreement provides for a maximum facility amount of $1.5 billion and matures on June 6, 2018. On February 19, 2016, the Company further amended its revolving credit facility to, among other things, (a) increase the basket for unsecured debt issuances to $1.4 billion from $1.2 billion (of which $950 million was then outstanding), (b) reaffirm the Company's borrowing base of $700.0 million, and (c) increase the percentage of projected oil and gas production that may be hedged by the Company during 2016. On December 13, 2016, the Company further amended its revolving credit facility to, among other things, (a) reset the maturity date to December 31, 2021, (b) adjust lenders, (c) increase the basket for unsecured debt issuances to $1.6 billion, (d) increase the interest rates by 50 basis points, (e) increase the mortgage requirement to 85% (from 80%), and (f) add deposit account control agreement language. As of December 31, 2016, the Company did not have any outstanding borrowing under the Amended and Restated Credit Agreement. At December 31, 2016, the total availability for future borrowings under Amended and Restated Credit Agreement, after giving effect to an aggregate of $209.7 million of letters of credit, was $490.3 million. The Company's wholly-owned subsidiaries have guaranteed the obligations of the Company under the Amended and Restated Credit Agreement.Advances under the Amended and Restated Credit Agreement may be in the form of either base rate loans or eurodollar loans. The interest rate for base rate loans is equal to (1) the applicable rate, which ranges from 1.00% to 2.00%, plus (2) the highest of: (a) the federal funds rate plus 0.50%, (b) the rate of interest in effect for such day as publicly announced from time to time by agent as its “prime rate,” and (c) the eurodollar rate for an interest period of one month plus 1.00%. The interest rate for eurodollar loans is equal to (1) the applicable rate, which ranges from 2.00% to 3.00%, plus (2) the London interbank offered rate that appears on pages LIBOR01 or LIBOR02 of the Reuters screen that displays such rate for deposits in U.S. dollars, or, if such rate is not available, the rate as administered by ICE Benchmark Administration (or any other person that takes over administration of such rate) per annum equal to the offered rate on such other page or service that displays on average London interbank offered rate as determined by ICE Benchmark Administration (or any other person that takes over administration of such rate) for deposits in U.S. dollars, or, if such rate is not available, the average quotations for three major New York money center banks of whom the agent shall inquire as the “London Interbank Offered Rate” for deposits in U.S. dollars.The Amended and Restated Credit Agreement contains customary negative covenants including, but not limited to, restrictions on the Company’s and its subsidiaries’ ability to: •incur indebtedness; •grant liens; •pay dividends and make other restricted payments; •make investments; •make fundamental changes; •enter into swap contracts and forward sales contracts; •dispose of assets; •change the nature of their business; and •enter into transactions with affiliates. The negative covenants are subject to certain exceptions as specified in the Amended and Restated Credit Agreement. The Amended and Restated Credit Agreement also contains certain affirmative covenants, including, but not limited to the following financial covenants: (i) the ratio of net funded debt to EBITDAX (net income, excluding (i) any non-cash revenue or expense associated with swap contracts resulting from ASC 815 and (ii) any cash or noncash revenue or expense attributable to minority investments plus without duplication and, in the case of expenses, to the extent deducted from revenues in determining net income, the sum of (a) the aggregate amount of consolidated interest expense for such period, (b) the aggregate amount of income, franchise, capital or similar tax expense (other than ad valorem taxes) for such period, (c) all amounts attributable to depletion, depreciation, amortization and asset or goodwill impairment or writedown for such period, (d) all other non-cash charges, (e) exploration costs deducted in determining net income under successful efforts accounting, (f) actual cash distributions received from minority investments, (g) to the extent actually reimbursed by insurance, expenses with respect to liability on casualty events or business interruption, and (h) all reasonable transaction expenses related to dispositions and acquisitions of assets, investments and debt and equity offerings (provided that expenses related to any unsuccessful disposition will be limited to $3.0 million in the aggregate) for a twelve-month period may not be greater than 4.00 to 1.00; and (ii) the ratio of EBITDAX to interest expense for a twelve-month period may not be less than 3.00 to 1.00. The Company was in compliance with all covenants at December 31, 2016.

[5] On June 4, 2015, the Company entered into a construction loan agreement (the "Construction Loan") with InterBank for the construction of a new corporate headquarters in Oklahoma City. The Construction Loan allows for maximum principal borrowings of $24.5 million and requires the Company to fund 30% of the cost of the construction before any funds can be drawn, which occurred in January 2016. Interest accrues daily on the outstanding principal balance at a fixed rate of 4.50% per annum and is payable on the last day of the month through May 31, 2017. Monthly interest and principal payments are due beginning June 30, 2017, with the final payment due June 4, 2025. At December 31, 2016, the total borrowings under the Construction loan were approximately $21.0 million.

[6] On April 21, 2015, the Company issued $350.0 million in aggregate principal amount of 6.625% Senior Notes due 2023 (the "2023 Notes") to qualified institutional buyers pursuant to Rule 144A under the Securities Act and to certain non-U.S. persons in accordance with Regulation S under the Securities Act (the "2023 Notes Offering"). The Company received net proceeds of approximately $343.6 million after initial purchaser discounts and commissions and estimated offering expenses.The 2023 Notes were issued under an indenture, dated as of April 21, 2015, among the Company, the subsidiary guarantors party thereto and Wells Fargo Bank, National Association, as trustee. Pursuant to the indenture relating to the 2023 Notes, interest on the 2023 Notes will accrue at a rate of 6.625% per annum on the outstanding principal amount thereof from April 21, 2015, payable semi-annually on May 1 and November 1 of each year, commencing on November 1, 2015. The 2023 Notes are not guaranteed by Grizzly Holdings, Inc. and will not be guaranteed by any of the Company's future unrestricted subsidiaries.In connection with the 2023 Notes Offering, the Company and its subsidiary guarantors entered into a registration rights agreement, dated as of April 21, 2015, pursuant to which the Company agreed to file a registration statement with respect to an offer to exchange the 2023 Notes for a new issue of substantially identical debt securities registered under the Securities Act. The exchange offer for the 2023 Notes was completed on October 13, 2015.

[7] On October 17, 2012, the Company issued $250.0 million in aggregate principal amount of Senior Notes due 2020 (the "October Notes") under an indenture among the Company, its subsidiary guarantors and Wells Fargo Bank, National Association, as the trustee, (the "senior note indenture"). On December 21, 2012, the Company issued an additional $50.0 million in aggregate principal amount of 7.75% Senior Notes due 2020 (the "December Notes") as additional securities under the senior note indenture. On August 18, 2014, the Company issued an additional $300.0 million in aggregate principal amount of 7.75% Senior Notes due 2020 (the "August Notes"). The August Notes were issued as additional securities under the senior note indenture. The October Notes, December Notes and the August Notes are collectively referred to as the "2020 Notes."On October 6, 2016, the Company commenced a cash tender offer to purchase any and all of its 2020 Notes, which tender offer expired on October 13, 2016 and settled on October 14, 2016. Holders of the 2020 Notes that were validly tendered and accepted at or prior to the expiration time of the tender offer, or who delivered the 2020 Notes pursuant to the guaranteed delivery procedures, received total cash consideration of $1,042 per $1,000 principal amount of notes, plus any accrued and unpaid interest up to, but not including, the settlement date. An aggregate of $403.5 million in principal amount of the 2020 Notes was validly tendered in the tender offer. The remaining 2020 Notes that were not tendered in the tender offer were redeemed by the Company. The redemption payment included approximately $196.5 million in aggregate principal amount at a redemption price of 103.875% of the principal amount of the redeemed 2020 Notes, plus accrued and unpaid interest thereon to the redemption date. Upon deposit of the redemption payment with the paying agent on October 14, 2016, the indenture governing the 2020 Notes was fully satisfied and discharged. The cash tender offer for the 2020 Notes and redemption of the remaining 2020 Notes were funded with the net proceeds from the offering of the 6.000% Senior Notes due 2024 (the “2024 Notes”) as discussed below and cash on hand.

[8] On October 14, 2016, the Company issued the 2024 Notes in aggregate principal amount of $650.0 million. The 2024 Notes were issued under an indenture, dated as of October 14, 2016, among the Company, the subsidiary guarantors party thereto and the senior note indenture trustee (the "2024 Indenture"), to qualified institutional buyers pursuant to Rule 144A under the Securities Act and to certain non-U.S. persons in accordance with Regulation S under the Securities Act (the “2024 Notes Offering”). Under the 2024 Indenture, interest on the 2024 Notes accrues at a rate of 6.000% per annum on the outstanding principal amount thereof from October 14, 2016, payable semi-annually on April 15 and October 15 of each year, commencing on April 15, 2017. The 2024 Notes will mature on October 15, 2024. The Company received approximately $638.9 million in net proceeds from the offering of the 2024 Notes, which was used, together with cash on hand, to purchase the outstanding 2020 Notes in a concurrent cash tender offer, to pay fees and expenses thereof, and to redeem any of the 2020 Notes that remained outstanding after the completion of the tender offer.

[9] On December 21, 2016, the Company issued $600.0 million in aggregate principal amount of 6.375% Senior Notes due 2025 (the “2025 Notes”). The 2025 Notes were issued under an indenture, dated as of December 21, 2016, among the Company, the subsidiary guarantors party thereto and the senior note indenture trustee (the "2025 Indenture"), to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, and to certain non-U.S. persons in accordance with Regulation S under the Securities Act. Under the 2025 Indenture, interest on the 2025 Notes accrues at a rate of 6.375% per annum on the outstanding principal amount thereof from December 21, 2016, payable semi-annually on May 15 and November 15 of each year, commencing on May 15, 2017. The 2025 Notes will mature on May 15, 2025. The Company received approximately $590.8 million in net proceeds from the offering of the 2025 Notes, which the Company intends to use, together with the net proceeds from the Company's December 2016 common stock offering and cash on hand, to fund the cash portion of the purchase price for the pending acquisition of certain assets from Vitruvian II Woodford, LLC ("Vitruvian"). See Note 15 for more details on the pending Vitruvian Acquisition.