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Compensation Plans Non Stock-Based Compensation (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Net Profits Plan [Member] |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |
Minimum Percentage of Oil and Gas Wells, Costs Recovered for Payment to Employees from Net Profit Plan | 100.00% |  |
Percentage of Future Net Cash Flow Received by Participants from Net Profit Plan | 10.00% |  |
Percentage Of Future Net Cash Flow Received By Participants From Net Profit Plan Increased To | 20.00% |  |
Percentage of Oil and Gas Wells Costs Recovered for Additional Payment Employees from Net Profit Plan | 200.00% |  |
Total Cash Payments, Made or Accrued under Profit Sharing Plan | $ (54) | $ 6,608 | $ 3,498
Cash Payments Made or Accrued under Profit Sharing Plan Related to Divested Property | 2,753 | 24,349 | 3,789
Total net settlements under Profit Sharing Plan | $ 2,699 | 30,957 | 7,287
401K Plan [Member] |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent | 60.00% |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay, Employees Hired December 31, 2014 and Prior | 6.00% |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay, Employees Hired After December 31, 2014 | 9.00% |  |
Defined Contribution Plan, Cost | $ 4,500 | $ 5,400 | $ 5,600

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- Definition Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay, Employees Hired After December 31, 2014 + References No definition available. + Details
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- Definition Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay, Employees Hired December 31, 2014 and Prior + References No definition available. + Details
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- Definition Represents the minimum percentage of total costs required to be recovered for payment of net profit plan. + References No definition available. + Details
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- Definition Represents the percentage of future net cash payment to employees from the net profit plan. + References No definition available. + Details
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- Definition Represents the percentage of future net cash payment to employees from the net profit plan. + References No definition available. + Details
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- Definition Represents the percentage of total costs required to be recovered for additional payment from the net profit plan. + References No definition available. + Details
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- Definition Total amount expensed related to cash payments made or accrued under the profit sharing plan. + References No definition available. + Details
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- Definition Total net settlements under Profit Sharing Plan + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
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