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Long-Term Debt - Additional Information (Details) |  |  |  |  |  | 1 Months Ended | 12 Months Ended |  |  |  |  |  |
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May 21, 2018 USD ($) | Nov. 21, 2017 | May 04, 2017 USD ($) bank | Dec. 21, 2016 USD ($) | Oct. 14, 2016 USD ($) | Jan. 31, 2016 | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Nov. 28, 2018 USD ($) | Oct. 11, 2017 USD ($) | May 03, 2017 USD ($) | Mar. 29, 2017 USD ($) | Jun. 04, 2015 USD ($) | Apr. 21, 2015 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-tern debt |  |  |  |  |  |  | $ 2,118,149,000 |  |  |  |  |  |  |  |
Deferred finance costs |  |  |  |  |  |  | 30,733,000 | $ 34,781,000 |  |  |  |  |  |  |
Capitalized interest costs |  |  |  |  |  |  | 4,470,000 | 9,470,000 | $ 9,148,000 |  |  |  |  |  |
Revolving credit agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt issued |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |
Construction loans |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt issued |  |  |  |  |  |  | 23,149,000 | 23,724,000 |  |  |  |  |  |  |
Oil and gas properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capitalized interest costs |  |  |  |  |  |  | $ 4,500,000 | $ 9,500,000 |  |  |  |  |  |  |
Nova Scotia, Amegy, KeyBank | Revolving credit agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weight average interest rate |  |  |  |  |  |  | 4.23% |  |  |  |  |  |  |  |
Nova Scotia, Amegy, KeyBank | Base Rate | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  |  |  |  | 0.25% |  |  |  |  |  |  |  |
Nova Scotia, Amegy, KeyBank | Base Rate | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  |  |  |  | 1.25% |  |  |  |  |  |  |  |
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 |  |  |  |  |  |  | 1.25% |  |  |  |  |  |  |  |
Nova Scotia, Amegy, KeyBank | Eurodollar | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  |  |  |  | 2.25% |  |  |  |  |  |  |  |
InterBank | Revolving credit agreement | Construction loans |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 24,500,000 |
Stated interest rate |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.50% |
InterBank | Letter of credit | Construction loans |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required minimum down payment percentage |  |  |  |  |  | 30.00% |  |  |  |  |  |  |  |  |
Deferred finance costs |  |  |  |  |  |  | $ 100,000 |  |  |  |  |  |  |  |
Debt issued |  |  |  |  |  |  | $ 23,100,000 |  |  |  |  |  |  |  |
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 | Revolving credit agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  |  |  |  |  | $ 1,500,000,000 |  |  |  |  |  |  |  |
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank | Revolving credit agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowing base | $ 1,400,000,000.0 |  | $ 1,000,000,000.0 |  |  |  | 1,200,000,000.0 |  |  |  |  | $ 700,000,000.0 |  |  |
Minimum acquisition payment limit |  |  |  |  |  |  |  |  |  |  |  |  | $ 50,000,000.0 |  |
Minimum disposition of property limit |  |  |  |  |  |  |  |  |  |  |  |  | $ 50,000,000.0 |  |
Number of banks added to syndicate | bank |  |  | 5 |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in interest rate | (0.25%) | 0.50% |  |  |  |  |  |  |  |  |  |  |  |  |
Debt issued |  |  |  |  |  |  | 45,000,000 |  |  |  |  |  |  |  |
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank | Letter of credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term line of credit outstanding |  |  |  |  |  |  | 316,600,000 |  |  |  |  |  |  |  |
Line of credit facility, elected commitment | $ 1,000,000,000.0 |  |  |  |  |  | 1,000,000,000.0 |  |  | $ 1,000,000,000.0 |  |  |  |  |
Future borrowings available |  |  |  |  |  |  | 638,400,000 |  |  |  |  |  |  |  |
Disposition costs, maximum expenses allowed |  |  |  |  |  |  | $ 3,000,000.0 |  |  |  |  |  |  |  |
7.75% Senior Notes Due 2020 | Senior notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  |  |  |  | 7.75% | 7.75% |  |  |  |  |  |  |
6.625% Senior Notes Due 2023 | Senior notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  |  |  |  | 6.625% | 6.625% |  |  |  |  |  |  | 6.625%
Long-tern debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 343,600,000
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 350,000,000.0
Deferred finance costs |  |  |  |  |  |  | $ 4,400,000 |  |  |  |  |  |  |  |
Debt issued |  |  |  |  |  |  | $ 350,000,000 | $ 350,000,000 |  |  |  |  |  |  |
6.000% Senior Notes Due 2024 | Senior notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  |  | 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 |  |  |  |  |  |  | $ 8,700,000 |  |  |  |  |  |  |  |
Debt issued |  |  |  |  |  |  | $ 650,000,000 | $ 650,000,000 |  |  |  |  |  |  |
6.375% Senior Notes Due 2025 | Senior notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  | 6.375% |  |  | 6.375% | 6.375% |  |  |  |  |  |  |
Aggregate principal amount |  |  |  | $ 600,000,000 |  |  |  |  |  |  |  |  |  |  |
Proceeds from issuance of Senior notes |  |  |  | $ 584,700,000 |  |  |  |  |  |  |  |  |  |  |
Deferred finance costs |  |  |  |  |  |  | $ 12,500,000 |  |  |  |  |  |  |  |
Debt issued |  |  |  |  |  |  | $ 600,000,000 | $ 600,000,000 |  |  |  |  |  |  |
6.375% Senior Notes Due 2026 | Senior notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  |  |  |  | 6.375% | 6.375% |  |  | 6.375% |  |  |  |
Long-tern debt |  |  |  |  |  |  |  |  |  |  | $ 444,100,000 |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  | $ 450,000,000 |  |  |  |
Deferred finance costs |  |  |  |  |  |  | $ 5,000,000 |  |  |  |  |  |  |  |
Debt issued |  |  |  |  |  |  | $ 450,000,000 | $ 450,000,000 |  |  |  |  |  |  |

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- Definition Debt Instrument, Covenant Terms, Minimum Acquisition Payment Limit + References No definition available. + Details
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- Definition Debt Instrument, Number of Banks Added to Syndicate + References No definition available. + Details
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- Definition Line of Credit Facility, Required Minimum Down Payment, Percent + References No definition available. + Details
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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
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- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
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- Definition The average effective interest rate during the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399 + Details
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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