$UNTC
UNIT CORP Stock $untc

$untc Overview Financials Valuation SEC Filings Company Website

2017 Q4 Form 10-K Financial Statement

#000079894918000008 Filed on February 27, 2018

Income Statement

Concept	2017 Q4	2016 Q4	2016 Q3
Revenue	$204.8M	$174.3M	$153.4M
YoY Change	17.54%	1.15%	-27.77%
Cost Of Revenue	$109.9M	$87.60M	$130.8M
YoY Change	25.46%	-51.25%	-33.57%
Gross Profit	$37.21M	$36.78M	-$26.89M
YoY Change	1.17%	-107.46%	-91.45%
Gross Profit Margin	18.17%	21.11%	-17.53%
Selling, General & Admin	$11.20M	$7.300M	$8.900M
YoY Change	53.42%	-16.09%	17.11%
% of Gross Profit	30.1%	19.85%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$57.80M	$48.40M	$49.97M
YoY Change	19.42%	-35.55%	250.54%
% of Gross Profit	155.33%	131.59%
Operating Expenses	$68.90M	$57.40M	$180.3M
YoY Change	20.03%	559.77%	-65.77%
Operating Profit	-$31.69M	-$20.62M	-$26.81M
YoY Change	53.7%	-95.89%	-91.47%
Interest Expense	-$15.80M	-$27.60M	-$3.000M
YoY Change	-42.75%	-663.27%
% of Operating Profit
Other Income/Expense, Net	$0.00	$300.0K	-$3.030M
YoY Change	-100.0%		15050.0%
Pretax Income	$9.400M	$3.600M	-$38.62M
YoY Change	161.11%	-100.72%	-88.27%
Income Tax	$1.500M	$2.000M	-$14.60M
% Of Pretax Income	15.96%	55.56%
Net Earnings	$89.16M	$1.683M	-$24.02M
YoY Change	5197.39%	-100.54%	-88.3%
Net Earnings / Revenue	43.52%	0.97%	-15.66%
Basic Earnings Per Share	$1.74	$0.03	-$0.48
Diluted Earnings Per Share	$1.71	$0.03	-$0.48
COMMON SHARES
Basic Shares Outstanding	52.88M shares	51.49M shares	50.08M shares
Diluted Shares Outstanding			50.08M shares

Balance Sheet

Concept	2017 Q4	2016 Q4	2016 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$700.0K	$900.0K	$900.0K
YoY Change	-22.22%	12.5%	0.0%
Cash & Equivalents	$701.0K	$893.0K	$913.0K
Short-Term Investments
Other Short-Term Assets	$6.900M	$32.90M	$17.10M
YoY Change	-79.03%	-5.73%	-53.02%
Inventory	$500.0K	$3.300M	$3.300M
Prepaid Expenses
Receivables	$111.5M	$83.95M	$71.96M
Other Receivables	$0.00	$100.0K	$300.0K
Total Short-Term Assets	$119.7M	$121.2M	$93.65M
YoY Change	-1.26%	-13.59%	-37.85%
LONG-TERM ASSETS
Property, Plant & Equipment	$2.383B	$2.281B	$2.310B
YoY Change	4.46%	-11.62%	-24.17%
Goodwill	$62.81M	$62.81M	$62.81M
YoY Change	0.0%	0.0%	0.0%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$16.23M	$13.82M	$14.16M
YoY Change	17.46%	-5.89%	-4.98%
Total Long-Term Assets	$2.462B	$2.358B	$2.388B
YoY Change	4.4%	-11.34%	-23.81%
TOTAL ASSETS
Total Short-Term Assets	$119.7M	$121.2M	$93.65M
Total Long-Term Assets	$2.462B	$2.358B	$2.388B
Total Assets	$2.581B	$2.479B	$2.481B
YoY Change	4.12%	-11.45%	-24.46%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$112.6M	$88.79M	$56.38M
YoY Change	26.87%	1.58%	-42.18%
Accrued Expenses	$48.52M	$39.65M	$57.72M
YoY Change	22.38%	-15.49%	-15.17%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$181.9M	$164.9M	$136.0M
YoY Change	10.32%	9.29%	-25.43%
LONG-TERM LIABILITIES
Long-Term Debt	$820.3M	$800.9M	$854.6M
YoY Change	2.42%	-12.85%	-5.91%
Other Long-Term Liabilities	$100.2M	$103.1M	$103.7M
YoY Change	-2.78%	-26.56%	-24.33%
Total Long-Term Liabilities	$920.5M	$904.0M	$958.2M
YoY Change	1.83%	-14.67%	-8.32%
TOTAL LIABILITIES
Total Short-Term Liabilities	$181.9M	$164.9M	$136.0M
Total Long-Term Liabilities	$920.5M	$904.0M	$958.2M
Total Liabilities	$1.102B	$1.069B	$1.094B
YoY Change	3.14%	-11.68%	-10.86%
SHAREHOLDERS EQUITY
Retained Earnings	$799.4M	$681.6M	$679.9M
YoY Change	17.29%	-16.6%	-39.65%
Common Stock	$10.28M	$10.02M	$10.02M
YoY Change	2.64%	1.88%	1.88%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$1.346B	$1.194B	$1.190B
YoY Change
Total Liabilities & Shareholders Equity	$2.581B	$2.479B	$2.481B
YoY Change	4.12%	-11.45%	-24.46%

Cashflow Statement

Concept	2017 Q4	2016 Q4	2016 Q3
OPERATING ACTIVITIES
Net Income	$89.16M	$1.683M	-$24.02M
YoY Change	5197.39%	-100.54%	-88.3%
Depreciation, Depletion And Amortization	$57.80M	$48.40M	$49.97M
YoY Change	19.42%	-35.55%	250.54%
Cash From Operating Activities	$85.30M	$42.30M	$65.10M
YoY Change	101.65%	-35.32%	-47.46%
INVESTING ACTIVITIES
Capital Expenditures	$88.20M	$32.10M	$30.40M
YoY Change	174.77%	-58.63%	-72.95%
Acquisitions
YoY Change
Other Investing Activities	-$1.000M	$28.70M	$200.0K
YoY Change	-103.48%	1266.67%	-95.74%
Cash From Investing Activities	-$89.20M	-$3.500M	-$30.10M
YoY Change	2448.57%	-95.37%	-72.08%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	3.800M	-38.90M	-35.00M
YoY Change	-109.77%	-489.0%	118.75%
NET CHANGE
Cash From Operating Activities	85.30M	42.30M	65.10M
Cash From Investing Activities	-89.20M	-3.500M	-30.10M
Cash From Financing Activities	3.800M	-38.90M	-35.00M
Net Change In Cash	-100.0K	-100.0K	0.00000003353
YoY Change	0.0%	-50.0%	-100.0%
FREE CASH FLOW
Cash From Operating Activities	$85.30M	$42.30M	$65.10M
Capital Expenditures	$88.20M	$32.10M	$30.40M
Free Cash Flow	-$2.900M	$10.20M	$34.70M
YoY Change	-128.43%	-183.61%	201.74%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2015Q4	unt	Contract Drilling Identifiable Assets ContractDrillingIdentifiableAssets	993015000	USD
CY2016Q4	unt	Contract Drilling Identifiable Assets ContractDrillingIdentifiableAssets	941676000	USD
CY2017Q4	unt	Contract Drilling Identifiable Assets ContractDrillingIdentifiableAssets	933063000	USD
CY2017	unt	Asset Retirement Obligation Liabilities Sold AssetRetirementObligationLiabilitiesSold	1735000	USD
CY2015Q4	unt	Capitalizedcostsofunprovedpropertiesincludedinamortizationcumulative Capitalizedcostsofunprovedpropertiesincludedinamortizationcumulative	114400000	USD
CY2017	dei	Amendment Flag AmendmentFlag	false
CY2017	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2017	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2017	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2017
CY2017	dei	Document Period End Date DocumentPeriodEndDate	2017-12-31
CY2017	dei	Document Type DocumentType	10-K
CY2017	dei	Entity Central Index Key EntityCentralIndexKey	0000798949
CY2018Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	53061832	shares
CY2017	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2017	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2017Q2	dei	Entity Public Float EntityPublicFloat	958140471	USD
CY2017	dei	Entity Registrant Name EntityRegistrantName	UNIT CORP
CY2017	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2017	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2017	dei	Trading Symbol TradingSymbol	unt
CY2016Q4	unt	Accrued Oil And Gas Production Expense Current AccruedOilAndGasProductionExpenseCurrent	10075000	USD
CY2017Q4	unt	Accrued Oil And Gas Production Expense Current AccruedOilAndGasProductionExpenseCurrent	11819000	USD
CY2016	unt	Asset Retirement Obligation Liabilities Sold AssetRetirementObligationLiabilitiesSold	10882000	USD
CY2016Q4	unt	Capitalizedcostsofunprovedpropertiesincludedinamortizationcumulative Capitalizedcostsofunprovedpropertiesincludedinamortizationcumulative	7600000	USD
CY2017Q4	unt	Capitalizedcostsofunprovedpropertiesincludedinamortizationcumulative Capitalizedcostsofunprovedpropertiesincludedinamortizationcumulative	10500000	USD
CY2017	unt	Capitalleasefairmarketvaluepercentageforpurchase Capitalleasefairmarketvaluepercentageforpurchase	0.10
CY2017Q4	unt	Capitalleasesfutureminimumpaymentsaverageannualpayment Capitalleasesfutureminimumpaymentsaverageannualpayment	4200000	USD
CY2017	unt	Capitalleaseterm Capitalleaseterm	P7Y
CY2015Q4	unt	Corporate Assets CorporateAssets	60240000	USD
CY2016Q4	unt	Corporate Assets CorporateAssets	52680000	USD
CY2017Q4	unt	Corporate Assets CorporateAssets	25064000	USD
CY2015Q4	unt	Corporatelandandbuildingnet Corporatelandandbuildingnet	49890000	USD
CY2016Q4	unt	Corporatelandandbuildingnet Corporatelandandbuildingnet	58188000	USD
CY2017Q4	unt	Corporatelandandbuildingnet Corporatelandandbuildingnet	56854000	USD
CY2015	unt	Costs Incurred In Asset Retirement Obligation CostsIncurredInAssetRetirementObligation	-5693000	USD
CY2016	unt	Costs Incurred In Asset Retirement Obligation CostsIncurredInAssetRetirementObligation	-30906000	USD
CY2017	unt	Costs Incurred In Asset Retirement Obligation CostsIncurredInAssetRetirementObligation	-3613000	USD
CY2017	unt	Current Ratio Of Credit Facility CurrentRatioOfCreditFacility	1 to 1
CY2017	unt	Debt Instrument Variable Interest Rate Payable Assessment Period DebtInstrumentVariableInterestRatePayableAssessmentPeriod	P90D
CY2016Q4	unt	Deferred Tax Assets Tax Deferred Expense Allowance For Losses And Nondeductible Accruals DeferredTaxAssetsTaxDeferredExpenseAllowanceForLossesAndNondeductibleAccruals	53967000	USD
CY2017Q4	unt	Deferred Tax Assets Tax Deferred Expense Allowance For Losses And Nondeductible Accruals DeferredTaxAssetsTaxDeferredExpenseAllowanceForLossesAndNondeductibleAccruals	32242000	USD
CY2016Q4	unt	Deferred Tax Liability Depreciation Depletion Amortization And Impairment DeferredTaxLiabilityDepreciationDepletionAmortizationAndImpairment	440690000	USD
CY2017Q4	unt	Deferred Tax Liability Depreciation Depletion Amortization And Impairment DeferredTaxLiabilityDepreciationDepletionAmortizationAndImpairment	324874000	USD
CY2017Q4	unt	Discountratecapitalleases Discountratecapitalleases	0.04
CY2015	unt	Eliminated Associated Operating Expense EliminatedAssociatedOperatingExpense	18300000	USD
CY2016	unt	Eliminated Associated Operating Expense EliminatedAssociatedOperatingExpense	0	USD
CY2017	unt	Eliminated Associated Operating Expense EliminatedAssociatedOperatingExpense	11800000	USD
CY2015	unt	Eliminated Yielding EliminatedYielding	3800000	USD
CY2016	unt	Eliminated Yielding EliminatedYielding	0	USD
CY2017	unt	Eliminated Yielding EliminatedYielding	1600000	USD
CY2017Q4	unt	Employee Service Share Based Compensation Allocation Of Unrecognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfUnrecognizedPeriodCostsCapitalizedAmount	1300000	USD
CY2015Q4	unt	Gas Gathering And Processing Identifiable Assets GasGatheringAndProcessingIdentifiableAssets	478661000	USD
CY2016Q4	unt	Gas Gathering And Processing Identifiable Assets GasGatheringAndProcessingIdentifiableAssets	461600000	USD
CY2017Q4	unt	Gas Gathering And Processing Identifiable Assets GasGatheringAndProcessingIdentifiableAssets	438571000	USD
CY2015	unt	General And Administrative Expense Reimbursement GeneralAndAdministrativeExpenseReimbursement	18000	USD
CY2016	unt	General And Administrative Expense Reimbursement GeneralAndAdministrativeExpenseReimbursement	6000	USD
CY2017	unt	General And Administrative Expense Reimbursement GeneralAndAdministrativeExpenseReimbursement	0	USD
CY2015	unt	Increase Decrease In Accounts Payable Related To Purchases Of Property Plant And Equipment IncreaseDecreaseInAccountsPayableRelatedToPurchasesOfPropertyPlantAndEquipment	105157000	USD
CY2016	unt	Increase Decrease In Accounts Payable Related To Purchases Of Property Plant And Equipment IncreaseDecreaseInAccountsPayableRelatedToPurchasesOfPropertyPlantAndEquipment	21190000	USD
CY2017	unt	Increase Decrease In Accounts Payable Related To Purchases Of Property Plant And Equipment IncreaseDecreaseInAccountsPayableRelatedToPurchasesOfPropertyPlantAndEquipment	-6942000	USD
CY2015	unt	Incremental Per Share Effect Of Dilutive Income Changes Over Dilutive Share Changes IncrementalPerShareEffectOfDilutiveIncomeChangesOverDilutiveShareChanges	0.00
CY2016	unt	Incremental Per Share Effect Of Dilutive Income Changes Over Dilutive Share Changes IncrementalPerShareEffectOfDilutiveIncomeChangesOverDilutiveShareChanges	0.00
CY2017	unt	Incremental Per Share Effect Of Dilutive Income Changes Over Dilutive Share Changes IncrementalPerShareEffectOfDilutiveIncomeChangesOverDilutiveShareChanges	-0.03
CY2017Q4	unt	Loan Origination Fees LoanOriginationFees	1000000	USD
CY2016Q4	unt	Natural Gas Gathering Systems And Treating Plants NaturalGasGatheringSystemsAndTreatingPlants	705859000	USD
CY2017Q4	unt	Natural Gas Gathering Systems And Treating Plants NaturalGasGatheringSystemsAndTreatingPlants	726236000	USD
CY2017	unt	Number Of Oil And Gas Limited Partnerships NumberOfOilAndGasLimitedPartnerships	13	Unit
CY2017	unt	Number Of Oil And Gas Limited Partnerships For Employee Investment NumberOfOilAndGasLimitedPartnershipsForEmployeeInvestment	13	Unit
CY2017	unt	Numberof Contracts Daywork NumberofContractsDaywork	9	contract
CY2017	unt	Numberof Contracts Daywork Expiringin Next Fiscal Year NumberofContractsDayworkExpiringinNextFiscalYear	8	contract
CY2017	unt	Numberof Contracts Daywork Expiringin Two Years NumberofContractsDayworkExpiringinTwoYears	1	contract
CY2017	unt	Numberofcompressorsundercapitalleaseagreement Numberofcompressorsundercapitalleaseagreement	20
CY2015	unt	Oil And Gas Properties Average Depreciation Depletion And Amortization Rate OilAndGasPropertiesAverageDepreciationDepletionAndAmortizationRate	12.30	USD
CY2016	unt	Oil And Gas Properties Average Depreciation Depletion And Amortization Rate OilAndGasPropertiesAverageDepreciationDepletionAndAmortizationRate	6.24	USD
CY2017	unt	Oil And Gas Properties Average Depreciation Depletion And Amortization Rate OilAndGasPropertiesAverageDepreciationDepletionAndAmortizationRate	6.00	USD
CY2017	unt	Oil And Gas Property Full Cost Method Discount Percentage OilAndGasPropertyFullCostMethodDiscountPercentage	0.10
CY2015Q4	unt	Oil And Natural Gas Identifiable Assets OilAndNaturalGasIdentifiableAssets	1218036000	USD
CY2016Q4	unt	Oil And Natural Gas Identifiable Assets OilAndNaturalGasIdentifiableAssets	965159000	USD
CY2017Q4	unt	Oil And Natural Gas Identifiable Assets OilAndNaturalGasIdentifiableAssets	1127900000	USD
CY2014	unt	Partnershipsdissolved Partnershipsdissolved	1	Partnerships
CY2015	unt	Partnershipsdissolved Partnershipsdissolved	0	Partnerships
CY2016	unt	Partnershipsdissolved Partnershipsdissolved	2	Partnerships
CY2017	unt	Partnershipsdissolved Partnershipsdissolved	0	Partnerships
CY2016	unt	Paymentsforproceedsfromderivativeinstrumentoperatingactivities Paymentsforproceedsfromderivativeinstrumentoperatingactivities	9658000	USD
CY2017	unt	Paymentsforproceedsfromderivativeinstrumentoperatingactivities Paymentsforproceedsfromderivativeinstrumentoperatingactivities	173000	USD
CY2015	unt	Percentage Of Annual Discount For Estimated Timing Of Cash Flows PercentageOfAnnualDiscountForEstimatedTimingOfCashFlows	0.10
CY2016	unt	Percentage Of Annual Discount For Estimated Timing Of Cash Flows PercentageOfAnnualDiscountForEstimatedTimingOfCashFlows	0.10
CY2016	unt	Total Gains Losses For Period Included In Earnings Attributable To Change In Gain Loss Relating To Assets TotalGainsLossesForPeriodIncludedInEarningsAttributableToChangeInGainLossRelatingToAssets	-16216000	USD
CY2017	unt	Total Gains Losses For Period Included In Earnings Attributable To Change In Gain Loss Relating To Assets TotalGainsLossesForPeriodIncludedInEarningsAttributableToChangeInGainLossRelatingToAssets	6916000	USD
CY2017Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	111512000	USD
CY2015Q4	unt	Total Identifiable Assets TotalIdentifiableAssets	2689712000	USD
CY2016Q4	unt	Total Identifiable Assets TotalIdentifiableAssets	2368435000	USD
CY2017	unt	Percentage Of Annual Discount For Estimated Timing Of Cash Flows PercentageOfAnnualDiscountForEstimatedTimingOfCashFlows	0.10
CY2017	unt	Percentagefairvalueexceedscarryingvalueforgoodwill Percentagefairvalueexceedscarryingvalueforgoodwill	0.41
CY2017	unt	Percentageofrepurchaseoflimitedunitsoutstanding Percentageofrepurchaseoflimitedunitsoutstanding	0.20
CY2015	unt	Proved Developed And Undeveloped Reserves Infill Reserves In Existing Proved Fields Energy ProvedDevelopedAndUndevelopedReservesInfillReservesInExistingProvedFieldsEnergy	6304000	MBoe
CY2016	unt	Proved Developed And Undeveloped Reserves Infill Reserves In Existing Proved Fields Energy ProvedDevelopedAndUndevelopedReservesInfillReservesInExistingProvedFieldsEnergy	7504000	MBoe
CY2017	unt	Proved Developed And Undeveloped Reserves Infill Reserves In Existing Proved Fields Energy ProvedDevelopedAndUndevelopedReservesInfillReservesInExistingProvedFieldsEnergy	16123000	MBoe
CY2015	unt	Repurchase Of Limited Units Outstanding Amount RepurchaseOfLimitedUnitsOutstandingAmount	118000	USD
CY2016	unt	Repurchase Of Limited Units Outstanding Amount RepurchaseOfLimitedUnitsOutstandingAmount	5000	USD
CY2017	unt	Repurchase Of Limited Units Outstanding Amount RepurchaseOfLimitedUnitsOutstandingAmount	2900	USD
CY2015	unt	Revenuesfromtransactionswithoperatingsegmentsofsameentity Revenuesfromtransactionswithoperatingsegmentsofsameentity	22100000	USD
CY2016	unt	Revenuesfromtransactionswithoperatingsegmentsofsameentity Revenuesfromtransactionswithoperatingsegmentsofsameentity	0	USD
CY2017	unt	Revenuesfromtransactionswithoperatingsegmentsofsameentity Revenuesfromtransactionswithoperatingsegmentsofsameentity	13400000	USD
CY2016Q4	unt	Saltwaterdisposalsystems Saltwaterdisposalsystems	60638000	USD
CY2017Q4	unt	Saltwaterdisposalsystems Saltwaterdisposalsystems	62618000	USD
CY2017	unt	Senior Notes Repurchase Price In Percentage SeniorNotesRepurchasePriceInPercentage	1.01
CY2016Q4	unt	Thirdpartycredits Thirdpartycredits	2998000	USD
CY2017Q4	unt	Thirdpartycredits Thirdpartycredits	2240000	USD
CY2015	unt	Total Capital Expenditures TotalCapitalExpenditures	454287000	USD
CY2016	unt	Total Capital Expenditures TotalCapitalExpenditures	142155000	USD
CY2017	unt	Total Capital Expenditures TotalCapitalExpenditures	332280000	USD
CY2017Q4	unt	Total Identifiable Assets TotalIdentifiableAssets	2499534000	USD
CY2017Q4	unt	Transfersbetween Level2and Level3assetsliabilities TransfersbetweenLevel2andLevel3assetsliabilities	0	USD
CY2015	unt	Well Supervision And Other Fees WellSupervisionAndOtherFees	423000	USD
CY2016	unt	Well Supervision And Other Fees WellSupervisionAndOtherFees	254000	USD
CY2017	unt	Well Supervision And Other Fees WellSupervisionAndOtherFees	172000	USD
CY2016Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	88793000	USD
CY2017Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	112648000	USD
CY2016Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	83954000	USD
CY2015	us-gaap	Accretion Expense AccretionExpense	3453000	USD
CY2016	us-gaap	Accretion Expense AccretionExpense	2779000	USD
CY2017	us-gaap	Accretion Expense AccretionExpense	2886000	USD
CY2016Q4	us-gaap	Accrued Employee Benefits Current AccruedEmployeeBenefitsCurrent	15394000	USD
CY2017Q4	us-gaap	Accrued Employee Benefits Current AccruedEmployeeBenefitsCurrent	19521000	USD
CY2016Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	39651000	USD
CY2017Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	48523000	USD
CY2016Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	5952330000	USD
CY2017Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	6151450000	USD
CY2014Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	0	USD
CY2015Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	0	USD
CY2016Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	0	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	63000	USD
CY2016Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	502500000	USD
CY2017Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	535815000	USD
CY2015	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	15300000	USD
CY2016	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	9600000	USD
CY2017	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	13300000	USD
CY2016Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	3773000	USD
CY2017Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	2450000	USD
CY2015	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	2088000	USD
CY2016	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	2122000	USD
CY2017	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	2159000	USD
CY2015Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	98297000	USD
CY2016Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	70170000	USD
CY2017Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	69444000	USD
CY2016	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	2779000	USD
CY2017	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	2886000	USD
CY2016Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	2906000	USD
CY2017Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	1726000	USD
CY2016	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	584000	USD
CY2017	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	1948000	USD
CY2016	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	1215000	USD
CY2017	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	2694000	USD
CY2016	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	19393000	USD
CY2017	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	1131000	USD
CY2016Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	67264000	USD
CY2017Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	67718000	USD
CY2015Q4	us-gaap	Assets Assets	2799842000	USD
CY2016Q4	us-gaap	Assets Assets	2479303000	USD
CY2017Q4	us-gaap	Assets Assets	2581452000	USD
CY2016Q4	us-gaap	Assets Current AssetsCurrent	121196000	USD
CY2017Q4	us-gaap	Assets Current AssetsCurrent	119672000	USD
CY2016Q4	us-gaap	Bank Overdrafts BankOverdrafts	17300000	USD
CY2017Q4	us-gaap	Bank Overdrafts BankOverdrafts	12400000	USD
CY2017Q4	us-gaap	Business Acquisition Purchase Price Allocation Goodwill Expected Tax Deductible Amount BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount	700000	USD
CY2016Q4	us-gaap	Capital Lease Obligations CapitalLeaseObligations	18918000	USD
CY2017Q4	us-gaap	Capital Lease Obligations CapitalLeaseObligations	15224000	USD
CY2017Q4	us-gaap	Capital Lease Obligations Current CapitalLeaseObligationsCurrent	3800000	USD
CY2017Q4	us-gaap	Capital Lease Obligations Noncurrent CapitalLeaseObligationsNoncurrent	11400000	USD
CY2017Q4	us-gaap	Capital Leases Future Minimum Payments Due CapitalLeasesFutureMinimumPaymentsDue	22272000	USD
CY2017Q4	us-gaap	Capital Leases Future Minimum Payments Due Current CapitalLeasesFutureMinimumPaymentsDueCurrent	6168000	USD
CY2017Q4	us-gaap	Capital Leases Future Minimum Payments Due In Four Years CapitalLeasesFutureMinimumPaymentsDueInFourYears	3768000	USD
CY2017Q4	us-gaap	Capital Leases Future Minimum Payments Due In Three Years CapitalLeasesFutureMinimumPaymentsDueInThreeYears	6168000	USD
CY2017Q4	us-gaap	Capital Leases Future Minimum Payments Due In Two Years CapitalLeasesFutureMinimumPaymentsDueInTwoYears	6168000	USD
CY2017Q4	us-gaap	Capital Leases Future Minimum Payments Executory Costs CapitalLeasesFutureMinimumPaymentsExecutoryCosts	5874000	USD
CY2017Q4	us-gaap	Capital Leases Future Minimum Payments Interest Included In Payments CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments	1174000	USD
CY2015Q4	us-gaap	Capitalized Costs Accumulated Depreciation Depletion Amortization And Valuation Allowance For Relating To Oil And Gas Producing Activities CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	4631404000	USD
CY2016Q4	us-gaap	Capitalized Costs Accumulated Depreciation Depletion Amortization And Valuation Allowance For Relating To Oil And Gas Producing Activities CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	4900304000	USD
CY2017Q4	us-gaap	Capitalized Costs Accumulated Depreciation Depletion Amortization And Valuation Allowance For Relating To Oil And Gas Producing Activities CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	4996696000	USD
CY2015Q4	us-gaap	Capitalized Costs Of Unproved Properties Excluded From Amortization Cumulative CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative	337099000	USD
CY2016Q4	us-gaap	Capitalized Costs Of Unproved Properties Excluded From Amortization Cumulative CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative	314867000	USD
CY2017Q4	us-gaap	Capitalized Costs Of Unproved Properties Excluded From Amortization Cumulative CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative	296764000	USD
CY2015Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Gross CapitalizedCostsOilAndGasProducingActivitiesGross	5738717000	USD
CY2016Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Gross CapitalizedCostsOilAndGasProducingActivitiesGross	5761172000	USD
CY2017Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Gross CapitalizedCostsOilAndGasProducingActivitiesGross	6009577000	USD
CY2015Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	1107313000	USD
CY2016Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	860868000	USD
CY2017Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	1012881000	USD
CY2015Q4	us-gaap	Capitalized Costs Proved Properties CapitalizedCostsProvedProperties	5401618000	USD
CY2016Q4	us-gaap	Capitalized Costs Proved Properties CapitalizedCostsProvedProperties	5446305000	USD
CY2017Q4	us-gaap	Capitalized Costs Proved Properties CapitalizedCostsProvedProperties	5712813000	USD
CY2016Q4	us-gaap	Capitalized Costs Support Equipment And Facilities CapitalizedCostsSupportEquipmentAndFacilities	1565268000	USD
CY2017Q4	us-gaap	Capitalized Costs Support Equipment And Facilities CapitalizedCostsSupportEquipmentAndFacilities	1593611000	USD
CY2015Q4	us-gaap	Capitalized Costs Wells And Related Equipment And Facilities CapitalizedCostsWellsAndRelatedEquipmentAndFacilities	19200000	USD
CY2016Q4	us-gaap	Capitalized Costs Wells And Related Equipment And Facilities CapitalizedCostsWellsAndRelatedEquipmentAndFacilities	15400000	USD
CY2017Q4	us-gaap	Capitalized Costs Wells And Related Equipment And Facilities CapitalizedCostsWellsAndRelatedEquipmentAndFacilities	14800000	USD
CY2014Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1049000	USD
CY2015Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	835000	USD
CY2016Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	893000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	701000	USD
CY2015	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-214000	USD
CY2016	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	58000	USD
CY2017	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-192000	USD
CY2017Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	0	USD
CY2016Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies	0	USD
CY2017Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies	0	USD
CY2016Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.2
CY2017Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.2
CY2016Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	175000000	shares
CY2017Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	175000000	shares
CY2016Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	51494318	shares
CY2017Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	52880134	shares
CY2016Q4	us-gaap	Common Stock Value CommonStockValue	10016000	USD
CY2017Q4	us-gaap	Common Stock Value CommonStockValue	10280000	USD
CY2015	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-1037361000	USD
CY2016	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-135624000	USD
CY2017	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	117911000	USD
CY2015	us-gaap	Cost Of Services Oil And Gas CostOfServicesOilAndGas	156408000	USD
CY2016	us-gaap	Cost Of Services Oil And Gas CostOfServicesOilAndGas	88154000	USD
CY2017	us-gaap	Cost Of Services Oil And Gas CostOfServicesOilAndGas	122600000	USD
CY2015	us-gaap	Costs And Expenses CostsAndExpenses	2512967000	USD
CY2016	us-gaap	Costs And Expenses CostsAndExpenses	746660000	USD
CY2017	us-gaap	Costs And Expenses CostsAndExpenses	655889000	USD
CY2015	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties With Proved Reserves CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves	179000	USD
CY2016	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties With Proved Reserves CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves	564000	USD
CY2017	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties With Proved Reserves CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves	47638000	USD
CY2015	us-gaap	Costs Incurred Acquisition Of Unproved Oil And Gas Properties CostsIncurredAcquisitionOfUnprovedOilAndGasProperties	41777000	USD
CY2016	us-gaap	Costs Incurred Acquisition Of Unproved Oil And Gas Properties CostsIncurredAcquisitionOfUnprovedOilAndGasProperties	21675000	USD
CY2017	us-gaap	Costs Incurred Acquisition Of Unproved Oil And Gas Properties CostsIncurredAcquisitionOfUnprovedOilAndGasProperties	47029000	USD
CY2015	us-gaap	Costs Incurred Development Costs CostsIncurredDevelopmentCosts	208845000	USD
CY2016	us-gaap	Costs Incurred Development Costs CostsIncurredDevelopmentCosts	80582000	USD
CY2017	us-gaap	Costs Incurred Development Costs CostsIncurredDevelopmentCosts	160941000	USD
CY2015	us-gaap	Costs Incurred Exploration Costs CostsIncurredExplorationCosts	19222000	USD
CY2016	us-gaap	Costs Incurred Exploration Costs CostsIncurredExplorationCosts	17325000	USD
CY2017	us-gaap	Costs Incurred Exploration Costs CostsIncurredExplorationCosts	14811000	USD
CY2015	us-gaap	Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities CostsIncurredOilAndGasPropertyAcquisitionExplorationAndDevelopmentActivities	264330000	USD
CY2016	us-gaap	Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities CostsIncurredOilAndGasPropertyAcquisitionExplorationAndDevelopmentActivities	89240000	USD
CY2017	us-gaap	Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities CostsIncurredOilAndGasPropertyAcquisitionExplorationAndDevelopmentActivities	266806000	USD
CY2015	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-20612000	USD
CY2016	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
CY2015	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-20616000	USD
CY2016	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	15000	USD
CY2017	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	5000	USD
CY2015	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-4000	USD
CY2016	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	15000	USD
CY2017	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	5000	USD
CY2016Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	810800000	USD
CY2017Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	828000000	USD
CY2016Q4	us-gaap	Debt Instrument Face Amount DebtInstrumentFaceAmount	650000000	USD
CY2017Q4	us-gaap	Debt Instrument Face Amount DebtInstrumentFaceAmount	650000000	USD
CY2017Q4	us-gaap	Debt Instrument Face Amount DebtInstrumentFaceAmount	650000000	USD
CY2017Q4	us-gaap	Debt Instrument Interest Rate Stated Percentage DebtInstrumentInterestRateStatedPercentage	0.06625
CY2017	us-gaap	Debt Instrument Interest Rate Terms DebtInstrumentInterestRateTerms	LIBOR plus 1.00% plus a margin
CY2017	us-gaap	Debt Instrument Maturity Date DebtInstrumentMaturityDate	2021-05-15
CY2016Q4	us-gaap	Debt Instrument Unamortized Discount DebtInstrumentUnamortizedDiscount	2800000	USD
CY2016Q4	us-gaap	Debt Instrument Unamortized Discount DebtInstrumentUnamortizedDiscount	2804000	USD
CY2017Q4	us-gaap	Debt Instrument Unamortized Discount DebtInstrumentUnamortizedDiscount	2234000	USD
CY2017Q4	us-gaap	Debt Instrument Unamortized Discount DebtInstrumentUnamortizedDiscount	2200000	USD
CY2015	us-gaap	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	3338000	USD
CY2016	us-gaap	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	17248000	USD
CY2017	us-gaap	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	1447000	USD
CY2016Q4	us-gaap	Deferred Compensation Liability Current And Noncurrent DeferredCompensationLiabilityCurrentAndNoncurrent	4578000	USD
CY2017Q4	us-gaap	Deferred Compensation Liability Current And Noncurrent DeferredCompensationLiabilityCurrentAndNoncurrent	5390000	USD
CY2015	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-535691000	USD
CY2016	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-62923000	USD
CY2017	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-62788000	USD
CY2016Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	7079000	USD
CY2017Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	5490000	USD
CY2015	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-606332000	USD
CY2016	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-71209000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-57683000	USD
CY2015	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-70641000	USD
CY2016	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-8286000	USD
CY2017	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	5105000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	249979000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	191397000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Net Current DeferredTaxAssetsNetCurrent	25211000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Net Current DeferredTaxAssetsNetCurrent	0	USD
CY2016Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	190603000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	153746000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Alternative Minimum Tax DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax	5409000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Alternative Minimum Tax DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax	5409000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	190711000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	133477000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	215922000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	133477000	USD
CY2015	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	352742000	USD
CY2016	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	208353000	USD
CY2017	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	209257000	USD
CY2016Q4	us-gaap	Derivative Assets DerivativeAssets	377000	USD
CY2017Q4	us-gaap	Derivative Assets DerivativeAssets	721000	USD
CY2016Q4	us-gaap	Derivative Assets Current DerivativeAssetsCurrent	0	USD
CY2017Q4	us-gaap	Derivative Assets Current DerivativeAssetsCurrent	721000	USD
CY2017Q4	us-gaap	Derivative Assets Liabilities At Fair Value Net DerivativeAssetsLiabilitiesAtFairValueNet	-7100000	USD
CY2016Q4	us-gaap	Derivative Assets Noncurrent DerivativeAssetsNoncurrent	377000	USD
CY2017Q4	us-gaap	Derivative Assets Noncurrent DerivativeAssetsNoncurrent	0	USD
CY2015	us-gaap	Derivative Cash Received On Hedge DerivativeCashReceivedOnHedge	-46615000	USD
CY2016	us-gaap	Derivative Cash Received On Hedge DerivativeCashReceivedOnHedge	-9658000	USD
CY2017	us-gaap	Derivative Cash Received On Hedge DerivativeCashReceivedOnHedge	-173000	USD
CY2016	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	-22813000	USD
CY2017	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	14732000	USD
CY2015	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	26345000	USD
CY2016	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	-22813000	USD
CY2017	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	14732000	USD
CY2016Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	21979000	USD
CY2017Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	7763000	USD
CY2016Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	21564000	USD
CY2017Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	7763000	USD
CY2016Q4	us-gaap	Derivative Liabilities Noncurrent DerivativeLiabilitiesNoncurrent	415000	USD
CY2017Q4	us-gaap	Derivative Liabilities Noncurrent DerivativeLiabilitiesNoncurrent	0	USD
CY2015	us-gaap	Dilutive Securities DilutiveSecurities	0	USD
CY2016	us-gaap	Dilutive Securities DilutiveSecurities	0	USD
CY2017	us-gaap	Dilutive Securities DilutiveSecurities	0	USD
CY2015	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-21.12
CY2016Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.83
CY2016Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-1.44
CY2016Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.48
CY2016Q4	us-gaap	Fair Value Concentration Of Risk Cash And Cash Equivalents FairValueConcentrationOfRiskCashAndCashEquivalents	8300000	USD
CY2017Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	3347396000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	228445000	USD
CY2016Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.03
CY2016	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-2.71
CY2017Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.32
CY2017Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.18
CY2017Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.07
CY2017Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.74
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.31
CY2015	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-21.12
CY2016Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.83
CY2016Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-1.44
CY2016Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.48
CY2016Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.03
CY2016	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-2.71
CY2017Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.31
CY2017Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.17
CY2017Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.07
CY2017Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.71
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.28
CY2016	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
CY2015	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	3500000	USD
CY2016	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	2100000	USD
CY2017	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	1800000	USD
CY2017Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	12800000	USD
CY2017	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P0Y8M12D
CY2015	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	5800000	USD
CY2016	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3600000	USD
CY2017	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	5000000	USD
CY2015	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	-3207000	USD
CY2016	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	-376000	USD
CY2017	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	0	USD
CY2015	us-gaap	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	95671000	USD
CY2016	us-gaap	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	84738000	USD
CY2017	us-gaap	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	102965000	USD
CY2017Q4	us-gaap	Fair Value Concentration Of Risk Cash And Cash Equivalents FairValueConcentrationOfRiskCashAndCashEquivalents	11400000	USD
CY2016	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-9042000	USD
CY2017	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	7791000	USD
CY2016	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases Sales Issuances Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements	-7174000	USD
CY2017	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases Sales Issuances Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements	-875000	USD
CY2015Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	9094000	USD
CY2016Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-7122000	USD
CY2017Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-206000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	2475898000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	2030925000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	173446000	USD
CY2017Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	369560000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	230544000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	141752000	USD
CY2017Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	234152000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	999132000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	854102000	USD
CY2017Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	1435440000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	1017777000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	861625000	USD
CY2017Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	1308244000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	409646000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	335892000	USD
CY2017Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	628270000	USD
CY2015	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-7229000	USD
CY2016	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	2540000	USD
CY2017	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	327000	USD
CY2015	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-7229000	USD
CY2016	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	2540000	USD
CY2017	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	327000	USD
CY2015	us-gaap	Gains Losses On Sales Of Assets GainsLossesOnSalesOfAssets	-7229000	USD
CY2016	us-gaap	Gains Losses On Sales Of Assets GainsLossesOnSalesOfAssets	3127000	USD
CY2017	us-gaap	Gains Losses On Sales Of Assets GainsLossesOnSalesOfAssets	327000	USD
CY2015	us-gaap	Gas Gathering Transportation Marketing And Processing Costs GasGatheringTransportationMarketingAndProcessingCosts	161556000	USD
CY2016	us-gaap	Gas Gathering Transportation Marketing And Processing Costs GasGatheringTransportationMarketingAndProcessingCosts	137609000	USD
CY2017	us-gaap	Gas Gathering Transportation Marketing And Processing Costs GasGatheringTransportationMarketingAndProcessingCosts	155483000	USD
CY2015	us-gaap	Gas Gathering Transportation Marketing And Processing Revenue GasGatheringTransportationMarketingAndProcessingRevenue	202789000	USD
CY2016	us-gaap	Gas Gathering Transportation Marketing And Processing Revenue GasGatheringTransportationMarketingAndProcessingRevenue	185870000	USD
CY2017	us-gaap	Gas Gathering Transportation Marketing And Processing Revenue GasGatheringTransportationMarketingAndProcessingRevenue	207176000	USD
CY2016Q4	us-gaap	Gas Imbalance Asset Liability GasImbalanceAssetLiability	-3789000	USD
CY2017Q4	us-gaap	Gas Imbalance Asset Liability GasImbalanceAssetLiability	-3283000	USD
CY2015	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	34358000	USD
CY2016	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	33337000	USD
CY2017	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	38087000	USD
CY2016Q4	us-gaap	Goodwill Goodwill	62808000	USD
CY2017Q4	us-gaap	Goodwill Goodwill	62808000	USD
CY2015	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
CY2016	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
CY2017	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
CY2015	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2016	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2017	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2016Q1	us-gaap	Gross Profit GrossProfit	-49745000	USD
CY2016Q2	us-gaap	Gross Profit GrossProfit	-73830000	USD
CY2016Q3	us-gaap	Gross Profit GrossProfit	-26893000	USD
CY2016Q4	us-gaap	Gross Profit GrossProfit	36782000	USD
CY2017Q1	us-gaap	Gross Profit GrossProfit	32657000	USD
CY2017Q2	us-gaap	Gross Profit GrossProfit	24462000	USD
CY2017Q3	us-gaap	Gross Profit GrossProfit	27181000	USD
CY2017Q4	us-gaap	Gross Profit GrossProfit	37211000	USD
CY2015	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-1658736000	USD
CY2016	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-144483000	USD
CY2017	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	83751000	USD
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-1664309000	USD
CY2016	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-206818000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	60170000	USD
CY2015	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-626948000	USD
CY2016	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-71194000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-57678000	USD
CY2015	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2016	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2017	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-81307000	USD
CY2015	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-582508000	USD
CY2016	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-72386000	USD
CY2017	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	21059000	USD
CY2015	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	1328000	USD
CY2016	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	1414000	USD
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	-952000	USD
CY2015	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	0	USD
CY2016	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	5465000	USD
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	1867000	USD
CY2015	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-45768000	USD
CY2016	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-5687000	USD
CY2017	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	1655000	USD
CY2015	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	3540000	USD
CY2016	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	42000	USD
CY2017	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	0	USD
CY2015	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-20306000	USD
CY2016	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	27400000	USD
CY2017	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	21824000	USD
CY2015	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-105426000	USD
CY2016	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	11796000	USD
CY2017	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	32073000	USD
CY2015	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	-22920000	USD
CY2016	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	-4388000	USD
CY2017	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	6996000	USD
CY2015	us-gaap	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	227857000	USD
CY2016	us-gaap	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	70976000	USD
CY2017	us-gaap	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	-5194000	USD
CY2016	us-gaap	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	44241000	USD
CY2017	us-gaap	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	-33389000	USD
CY2017Q4	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	505000	USD
CY2015	us-gaap	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	562838000	USD
CY2015	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	-21482000	USD
CY2016	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	20903000	USD
CY2017	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	38000	USD
CY2015	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-1507000	USD
CY2016	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-225000	USD
CY2017	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-2835000	USD
CY2015	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	-274000	USD
CY2016	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	-687000	USD
CY2017	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	1630000	USD
CY2015	us-gaap	Increase Decrease In Prepaid Expense IncreaseDecreaseInPrepaidExpense	-7134000	USD
CY2016	us-gaap	Increase Decrease In Prepaid Expense IncreaseDecreaseInPrepaidExpense	-2585000	USD
CY2017	us-gaap	Increase Decrease In Prepaid Expense IncreaseDecreaseInPrepaidExpense	-1527000	USD
CY2015	us-gaap	Increase Due To Purchases Of Minerals In Place IncreaseDueToPurchasesOfMineralsInPlace	0	USD
CY2016	us-gaap	Increase Due To Purchases Of Minerals In Place IncreaseDueToPurchasesOfMineralsInPlace	2652000	USD
CY2017	us-gaap	Increase Due To Purchases Of Minerals In Place IncreaseDueToPurchasesOfMineralsInPlace	51686000	USD
CY2015	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	21700000	USD
CY2016	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	15300000	USD
CY2017	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	15900000	USD
CY2015	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-31963000	USD
CY2016	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-39829000	USD
CY2017	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-38334000	USD
CY2015	us-gaap	Interest Paid Net InterestPaidNet	30910000	USD
CY2016	us-gaap	Interest Paid Net InterestPaidNet	35690000	USD
CY2017	us-gaap	Interest Paid Net InterestPaidNet	33931000	USD
CY2016Q4	us-gaap	Interest Payable Current InterestPayableCurrent	6524000	USD
CY2017Q4	us-gaap	Interest Payable Current InterestPayableCurrent	6745000	USD
CY2016Q4	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	3340000	USD
CY2016Q4	us-gaap	Land Land	59066000	USD
CY2017Q4	us-gaap	Land Land	59080000	USD
CY2017	us-gaap	Lease Expiration Date1 LeaseExpirationDate1	2021-12-31
CY2016Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2479303000	USD
CY2017Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2581452000	USD
CY2016Q4	us-gaap	Liabilities Current LiabilitiesCurrent	164915000	USD
CY2017Q4	us-gaap	Liabilities Current LiabilitiesCurrent	181936000	USD
CY2016Q4	us-gaap	Line Of Credit LineOfCredit	160800000	USD
CY2017Q4	us-gaap	Line Of Credit LineOfCredit	178000000	USD
CY2017	us-gaap	Line Of Credit Facility Commitment Fee Percentage LineOfCreditFacilityCommitmentFeePercentage	0.005
CY2016Q4	us-gaap	Line Of Credit Facility Interest Rate At Period End LineOfCreditFacilityInterestRateAtPeriodEnd	0.028
CY2017Q4	us-gaap	Line Of Credit Facility Interest Rate At Period End LineOfCreditFacilityInterestRateAtPeriodEnd	0.034
CY2017Q4	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	875000000	USD
CY2016Q4	us-gaap	Long Term Debt LongTermDebt	800917000	USD
CY2017Q4	us-gaap	Long Term Debt LongTermDebt	820276000	USD
CY2017Q4	us-gaap	Long Term Debt And Capital Lease Obligations Maturities Repayments Of Principal In Year Five LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalInYearFive	2100000	USD
CY2017Q4	us-gaap	Long Term Debt And Capital Lease Obligations Maturities Repayments Of Principal In Year Four LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalInYearFour	655900000	USD
CY2017Q4	us-gaap	Long Term Debt And Capital Lease Obligations Maturities Repayments Of Principal In Year Three LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalInYearThree	184700000	USD
CY2017Q4	us-gaap	Long Term Debt And Capital Lease Obligations Maturities Repayments Of Principal In Year Two LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalInYearTwo	45600000	USD
CY2017Q4	us-gaap	Long Term Debt And Capital Lease Obligations Repayments Of Principal In Next Twelve Months LongTermDebtAndCapitalLeaseObligationsRepaymentsOfPrincipalInNextTwelveMonths	13000000	USD
CY2017	us-gaap	Long Term Debt Maturities Repayment Terms LongTermDebtMaturitiesRepaymentTerms	4/10/2020
CY2016Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	800917000	USD
CY2017Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	820276000	USD
CY2016Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	32842000	USD
CY2017Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	29631000	USD
CY2015	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	102620000	USD
CY2016	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-129101000	USD
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	27218000	USD
CY2015	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-549778000	USD
CY2016	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-110971000	USD
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-306998000	USD
CY2015	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	446944000	USD
CY2016	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	240130000	USD
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	279588000	USD
CY2015	us-gaap	Net Income Loss NetIncomeLoss	-1037361000	USD
CY2016Q1	us-gaap	Net Income Loss NetIncomeLoss	-41149000	USD
CY2016Q2	us-gaap	Net Income Loss NetIncomeLoss	-72136000	USD
CY2016Q3	us-gaap	Net Income Loss NetIncomeLoss	-24022000	USD
CY2016Q4	us-gaap	Net Income Loss NetIncomeLoss	1683000	USD
CY2016	us-gaap	Net Income Loss NetIncomeLoss	-135624000	USD
CY2017Q1	us-gaap	Net Income Loss NetIncomeLoss	15929000	USD
CY2017Q2	us-gaap	Net Income Loss NetIncomeLoss	9059000	USD
CY2017Q3	us-gaap	Net Income Loss NetIncomeLoss	3705000	USD
CY2017Q4	us-gaap	Net Income Loss NetIncomeLoss	89155000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	117848000	USD
CY2015	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	-1037361000	USD
CY2016	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	-135624000	USD
CY2017	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	117848000	USD
CY2015	us-gaap	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	-1356333000	USD
CY2016	us-gaap	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	-94026000	USD
CY2017	us-gaap	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	236126000	USD
CY2015	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	-5573000	USD
CY2016	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	-62335000	USD
CY2017	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	-23581000	USD
CY2015	us-gaap	Oil And Gas Production Expense OilAndGasProductionExpense	166046000	USD
CY2016	us-gaap	Oil And Gas Production Expense OilAndGasProductionExpense	120184000	USD
CY2017	us-gaap	Oil And Gas Production Expense OilAndGasProductionExpense	130789000	USD
CY2015	us-gaap	Oil And Gas Revenue OilAndGasRevenue	385774000	USD
CY2016	us-gaap	Oil And Gas Revenue OilAndGasRevenue	294221000	USD
CY2017	us-gaap	Oil And Gas Revenue OilAndGasRevenue	357744000	USD
CY2015	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	484010000	USD
CY2016	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	345947000	USD
CY2017	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	408872000	USD
CY2015	us-gaap	Operating Expenses OperatingExpenses	2471380000	USD
CY2016	us-gaap	Operating Expenses OperatingExpenses	715863000	USD
CY2017	us-gaap	Operating Expenses OperatingExpenses	618129000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	100000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Receivable Current OperatingLeasesFutureMinimumPaymentsReceivableCurrent	2700000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Receivable In Three Years OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears	400000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Receivable In Two Years OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears	600000	USD
CY2015	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	12900000	USD
CY2016	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	11100000	USD
CY2017	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	8800000	USD
CY2017Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	587900000	USD
CY2016Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	2441000	USD
CY2017Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	4794000	USD
CY2015	us-gaap	Other Asset Impairment Charges OtherAssetImpairmentCharges	1634628000	USD
CY2016	us-gaap	Other Asset Impairment Charges OtherAssetImpairmentCharges	161563000	USD
CY2017	us-gaap	Other Asset Impairment Charges OtherAssetImpairmentCharges	0	USD
CY2016Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	13817000	USD
CY2017Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	16230000	USD
CY2015	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	0	USD
CY2016	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	0	USD
CY2017	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	63000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax	0	USD
CY2016	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax	63000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	0	USD
CY2016	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	102000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	0	USD
CY2016	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	63000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	0	USD
CY2016	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	39000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2016	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2015	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	0	USD
CY2016	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	39000	USD
CY2016Q4	us-gaap	Other Employee Related Liabilities Current And Noncurrent OtherEmployeeRelatedLiabilitiesCurrentAndNoncurrent	4943000	USD
CY2017Q4	us-gaap	Other Employee Related Liabilities Current And Noncurrent OtherEmployeeRelatedLiabilitiesCurrentAndNoncurrent	6524000	USD
CY2016Q4	us-gaap	Other Liabilities OtherLiabilities	117971000	USD
CY2017Q4	us-gaap	Other Liabilities OtherLiabilities	113205000	USD
CY2016Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	14907000	USD
CY2017Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	13002000	USD
CY2016Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	103064000	USD
CY2017Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	100203000	USD
CY2015	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	1517000	USD
CY2016	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	6037000	USD
CY2017	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	865000	USD
CY2015	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	45000	USD
CY2016	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	307000	USD
CY2017	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	21000	USD
CY2016Q4	us-gaap	Other Sundry Liabilities OtherSundryLiabilities	410000	USD
CY2017Q4	us-gaap	Other Sundry Liabilities OtherSundryLiabilities	0	USD
CY2017	us-gaap	Payment Of Financing And Stock Issuance Costs PaymentOfFinancingAndStockIssuanceCosts	14700000	USD
CY2015	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	0	USD
CY2016	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-919000	USD
CY2017	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	1500000	USD
CY2015	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	179000	USD
CY2016	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	564000	USD
CY2017	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	58026000	USD
CY2015	us-gaap	Proceeds From Repayments Of Bank Overdrafts ProceedsFromRepaymentsOfBankOverdrafts	-5624000	USD
CY2016	us-gaap	Proceeds From Repayments Of Bank Overdrafts ProceedsFromRepaymentsOfBankOverdrafts	-4829000	USD
CY2017	us-gaap	Proceeds From Repayments Of Bank Overdrafts ProceedsFromRepaymentsOfBankOverdrafts	-4911000	USD
CY2015	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	11854000	USD
CY2016	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	74823000	USD
CY2017	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	21713000	USD
CY2017Q4	us-gaap	Proved Developed And Undeveloped Reserve Net Energy ProvedDevelopedAndUndevelopedReserveNetEnergy	149774000	MBoe
CY2015	us-gaap	Proved Developed And Undeveloped Reserve Production Energy ProvedDevelopedAndUndevelopedReserveProductionEnergy	19981000	MBoe
CY2016	us-gaap	Proved Developed And Undeveloped Reserve Production Energy ProvedDevelopedAndUndevelopedReserveProductionEnergy	17277000	MBoe
CY2015	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	561453000	USD
CY2016	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	186149000	USD
CY2017	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	269185000	USD
CY2016Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	1
CY2017Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	1
CY2016Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2017Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2016Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2017Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2016Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2017Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2016Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	7798000	USD
CY2017Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	6233000	USD
CY2015	us-gaap	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	59117000	USD
CY2016	us-gaap	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	16602000	USD
CY2017	us-gaap	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	36044000	USD
CY2015	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	USD
CY2016	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	USD
CY2017	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	18623000	USD
CY2015	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	618500000	USD
CY2016	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	251398000	USD
CY2017	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	343900000	USD
CY2016Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	8233435000	USD
CY2017Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	8534192000	USD
CY2016Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	2281105000	USD
CY2017Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	2382742000	USD
CY2016Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	48590000	USD
CY2017Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	53439000	USD
CY2015	us-gaap	Proved Developed And Undeveloped Reserve Extension And Discovery Energy ProvedDevelopedAndUndevelopedReserveExtensionAndDiscoveryEnergy	6651000	MBoe
CY2016	us-gaap	Proved Developed And Undeveloped Reserve Extension And Discovery Energy ProvedDevelopedAndUndevelopedReserveExtensionAndDiscoveryEnergy	5690000	MBoe
CY2017	us-gaap	Proved Developed And Undeveloped Reserve Extension And Discovery Energy ProvedDevelopedAndUndevelopedReserveExtensionAndDiscoveryEnergy	14975000	MBoe
CY2014Q4	us-gaap	Proved Developed And Undeveloped Reserve Net Energy ProvedDevelopedAndUndevelopedReserveNetEnergy	179023000	MBoe
CY2015Q4	us-gaap	Proved Developed And Undeveloped Reserve Net Energy ProvedDevelopedAndUndevelopedReserveNetEnergy	135233000	MBoe
CY2016Q4	us-gaap	Proved Developed And Undeveloped Reserve Net Energy ProvedDevelopedAndUndevelopedReserveNetEnergy	117774000	MBoe
CY2017	us-gaap	Proved Developed And Undeveloped Reserve Production Energy ProvedDevelopedAndUndevelopedReserveProductionEnergy	15996000	MBoe
CY2017	us-gaap	Provision For Other Losses ProvisionForOtherLosses	348000	USD
CY2015	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	503500000	USD
CY2016	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	371600000	USD
CY2017	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	326700000	USD
CY2015	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	3549000	USD
CY2016	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	3694000	USD
CY2017	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	3694000	USD
CY2016	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	-62285000	USD
CY2017	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	87185000	USD
CY2015	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	152560000	USD
CY2016	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	108822000	USD
CY2015	us-gaap	Proved Developed And Undeveloped Reserve Purchase Of Mineral In Place Energy ProvedDevelopedAndUndevelopedReservePurchaseOfMineralInPlaceEnergy	0	MBoe
CY2016	us-gaap	Proved Developed And Undeveloped Reserve Purchase Of Mineral In Place Energy ProvedDevelopedAndUndevelopedReservePurchaseOfMineralInPlaceEnergy	262000	MBoe
CY2017	us-gaap	Proved Developed And Undeveloped Reserve Purchase Of Mineral In Place Energy ProvedDevelopedAndUndevelopedReservePurchaseOfMineralInPlaceEnergy	5768000	MBoe
CY2015	us-gaap	Proved Developed And Undeveloped Reserve Revision Of Previous Estimate Energy ProvedDevelopedAndUndevelopedReserveRevisionOfPreviousEstimateEnergy	-36573000	MBoe
CY2016	us-gaap	Proved Developed And Undeveloped Reserve Revision Of Previous Estimate Energy ProvedDevelopedAndUndevelopedReserveRevisionOfPreviousEstimateEnergy	-8300000	MBoe
CY2017	us-gaap	Proved Developed And Undeveloped Reserve Revision Of Previous Estimate Energy ProvedDevelopedAndUndevelopedReserveRevisionOfPreviousEstimateEnergy	11444000	MBoe
CY2015	us-gaap	Proved Developed And Undeveloped Reserves Sale Of Mineral In Place Energy ProvedDevelopedAndUndevelopedReservesSaleOfMineralInPlaceEnergy	191000	MBoe
CY2016	us-gaap	Proved Developed And Undeveloped Reserves Sale Of Mineral In Place Energy ProvedDevelopedAndUndevelopedReservesSaleOfMineralInPlaceEnergy	5338000	MBoe
CY2017	us-gaap	Proved Developed And Undeveloped Reserves Sale Of Mineral In Place Energy ProvedDevelopedAndUndevelopedReservesSaleOfMineralInPlaceEnergy	314000	MBoe
CY2014Q4	us-gaap	Proved Developed Reserves Boe1 ProvedDevelopedReservesBOE1	136790000	MBoe
CY2015Q4	us-gaap	Proved Developed Reserves Boe1 ProvedDevelopedReservesBOE1	115296000	MBoe
CY2016Q4	us-gaap	Proved Developed Reserves Boe1 ProvedDevelopedReservesBOE1	99079000	MBoe
CY2017Q4	us-gaap	Proved Developed Reserves Boe1 ProvedDevelopedReservesBOE1	112961000	MBoe
CY2014Q4	us-gaap	Proved Undeveloped Reserve Boe1 ProvedUndevelopedReserveBOE1	42233000	MBoe
CY2015Q4	us-gaap	Proved Undeveloped Reserve Boe1 ProvedUndevelopedReserveBOE1	19937000	MBoe
CY2016Q4	us-gaap	Proved Undeveloped Reserve Boe1 ProvedUndevelopedReserveBOE1	18695000	MBoe
CY2017Q4	us-gaap	Proved Undeveloped Reserve Boe1 ProvedUndevelopedReserveBOE1	36813000	MBoe
CY2015	us-gaap	Provision For Other Losses ProvisionForOtherLosses	1191000	USD
CY2016	us-gaap	Provision For Other Losses ProvisionForOtherLosses	785000	USD
CY2015	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	1844726000	USD
CY2016	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	268901000	USD
CY2017	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	96392000	USD
CY2015	us-gaap	Results Of Operations Income Before Income Taxes ResultsOfOperationsIncomeBeforeIncomeTaxes	-1625951000	USD
CY2016	us-gaap	Results Of Operations Income Before Income Taxes ResultsOfOperationsIncomeBeforeIncomeTaxes	-94981000	USD
CY2017	us-gaap	Results Of Operations Income Before Income Taxes ResultsOfOperationsIncomeBeforeIncomeTaxes	143561000	USD
CY2015	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	-612496000	USD
CY2016	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	-32696000	USD
CY2017	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	56376000	USD
CY2015	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	-1013455000	USD
CY2017	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	107332000	USD
CY2015	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	371335000	USD
CY2016	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	282742000	USD
CY2017	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	347285000	USD
CY2016Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	681554000	USD
CY2017Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	799402000	USD
CY2015	us-gaap	Revenue Oil And Gas Services RevenueOilAndGasServices	265668000	USD
CY2016	us-gaap	Revenue Oil And Gas Services RevenueOilAndGasServices	122086000	USD
CY2017	us-gaap	Revenue Oil And Gas Services RevenueOilAndGasServices	174720000	USD
CY2015	us-gaap	Revenues Revenues	854231000	USD
CY2016Q1	us-gaap	Revenues Revenues	136184000	USD
CY2016Q2	us-gaap	Revenues Revenues	138305000	USD
CY2016Q3	us-gaap	Revenues Revenues	153408000	USD
CY2016Q4	us-gaap	Revenues Revenues	174280000	USD
CY2016	us-gaap	Revenues Revenues	602177000	USD
CY2017Q1	us-gaap	Revenues Revenues	175724000	USD
CY2017Q2	us-gaap	Revenues Revenues	170581000	USD
CY2017Q3	us-gaap	Revenues Revenues	188488000	USD
CY2017Q4	us-gaap	Revenues Revenues	204847000	USD
CY2017	us-gaap	Revenues Revenues	739640000	USD
CY2015	us-gaap	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	-213945000	USD
CY2016	us-gaap	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	-51979000	USD
CY2017	us-gaap	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	87239000	USD
CY2015	us-gaap	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	-218115000	USD
CY2016	us-gaap	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	-173920000	USD
CY2017	us-gaap	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	-239953000	USD
CY2015	us-gaap	Settlement Of Asset Retirement Obligations Through Noncash Payments Amount SettlementOfAssetRetirementObligationsThroughNoncashPaymentsAmount	5694000	USD
CY2016	us-gaap	Settlement Of Asset Retirement Obligations Through Noncash Payments Amount SettlementOfAssetRetirementObligationsThroughNoncashPaymentsAmount	30897000	USD
CY2017	us-gaap	Settlement Of Asset Retirement Obligations Through Noncash Payments Amount SettlementOfAssetRetirementObligationsThroughNoncashPaymentsAmount	3613000	USD
CY2015	us-gaap	Share Based Compensation ShareBasedCompensation	21468000	USD
CY2016	us-gaap	Share Based Compensation ShareBasedCompensation	13812000	USD
CY2017	us-gaap	Share Based Compensation ShareBasedCompensation	17747000	USD
CY2015	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Of Proved Oil And Gas Reserves Other StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesOther	-209989000	USD
CY2016	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Of Proved Oil And Gas Reserves Other StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesOther	-22381000	USD
CY2017	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Of Proved Oil And Gas Reserves Other StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesOther	-2634000	USD
CY2015	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Of Proved Oil And Gas Reserves Period Increase Decrease StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease	-846258000	USD
CY2016	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Of Proved Oil And Gas Reserves Period Increase Decrease StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease	-71276000	USD
CY2017	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Of Proved Oil And Gas Reserves Period Increase Decrease StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease	288960000	USD
CY2015	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	209979000	USD
CY2016	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	69069000	USD
CY2017	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	57517000	USD
CY2014Q4	us-gaap	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1435744000	USD
CY2015Q4	us-gaap	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	589486000	USD
CY2016Q4	us-gaap	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	518210000	USD
CY2017Q4	us-gaap	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	807170000	USD
CY2015	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	18547000	USD
CY2016	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	16114000	USD
CY2017	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	14956000	USD
CY2015	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	0	shares
CY2016	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	0	shares
CY2017	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	787547000	shares
CY2015	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	819289000	shares
CY2016	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	1081217000	shares
CY2017	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	598269000	shares
CY2017	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	18623000	USD
CY2014Q4	us-gaap	Stockholders Equity StockholdersEquity	2332394000	USD
CY2016Q4	us-gaap	Workers Compensation Liability Current And Noncurrent WorkersCompensationLiabilityCurrentAndNoncurrent	15163000	USD
CY2017Q4	us-gaap	Workers Compensation Liability Current And Noncurrent WorkersCompensationLiabilityCurrentAndNoncurrent	13340000	USD
CY2015Q4	us-gaap	Stockholders Equity StockholdersEquity	1313580000	USD
CY2016Q4	us-gaap	Stockholders Equity StockholdersEquity	1194070000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	1345560000	USD
CY2016Q4	us-gaap	Taxes Payable Current TaxesPayableCurrent	2219000	USD
CY2017Q4	us-gaap	Taxes Payable Current TaxesPayableCurrent	3404000	USD
CY2015	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	26345000	USD
CY2016	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-22813000	USD
CY2017	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	14732000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	USD
CY2014Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	5039000	USD
CY2015Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	5199000	USD
CY2016Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3773000	USD
CY2017Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	2450000	USD
CY2015	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	1191000	USD
CY2016	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	785000	USD
CY2017	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	348000	USD
CY2015	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1031000	USD
CY2016	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	2211000	USD
CY2017	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1671000	USD
CY2015	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0	shares
CY2016	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0	shares
CY2017	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	635000	shares
CY2015	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	49110000	shares
CY2016	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	50029000	shares
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	51748000	shares
CY2015	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	49110000	shares
CY2016	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	50029000	shares
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	51113000	shares
CY2017	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-indent:30px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Financial instruments, which potentially subject us to concentrations of credit risk, consist primarily of trade receivables with a variety of oil and natural gas companies. We do not generally require collateral related to receivables. Our credit risk is considered to be limited due to the large number of customers comprising our customer base. Below are the third-party customers that accounted for more than 10% of our segment’s revenues: </font></div><div style="line-height:120%;font-size:10pt;"><div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;width:99.80506822612085%;border-collapse:collapse;text-align:left;"><tr><td colspan="9" rowspan="1"></td></tr><tr><td style="width:59%;" rowspan="1" colspan="1"></td><td style="width:12%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:12%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:12%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;font-weight:bold;">2017</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;font-weight:bold;">2016</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;font-weight:bold;">2015</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Oil and Natural Gas:</font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td></tr><tr><td style="vertical-align:top;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Sunoco Logistics Partners L.P.</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">10</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">24</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">19</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Valero Energy Corporation</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">9</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">11</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">15</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Drilling:</font></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">QEP Resources, Inc.</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">26</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">28</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">25</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Whiting Petroleum Corp. (formerly Kodiak Oil and Gas Corp.)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">7</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">18</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">7</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Mid-Stream:</font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td></tr><tr><td style="vertical-align:top;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">ONEOK, Inc.</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">36</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">30</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">29</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Range Resources Corporation</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">9</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">10</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">5</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Koch Energy Services, LLC</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">8</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">11</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">9</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Tenaska Resources, LLC</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">6</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">10</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">18</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Laclede Group, Inc.</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">1</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">9</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">12</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr></table></div><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">We had a concentration of cash of </font><font style="font-family:inherit;font-size:10pt;">$11.4 million</font><font style="font-family:inherit;font-size:10pt;"> and </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">$8.3 million</font><font style="font-family:inherit;font-size:10pt;"> at </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">December 31, 2017</font><font style="font-family:inherit;font-size:10pt;"> and </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">2016</font><font style="font-family:inherit;font-size:10pt;">, respectively with one bank.</font></div><div style="line-height:120%;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The use of derivative transactions also involves the risk that the counterparties will be unable to meet the financial terms of the transactions. We considered this non-performance risk with regard to our counterparties and our own non-performance risk in our derivative valuation at </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">December 31, 2017</font><font style="font-family:inherit;font-size:10pt;"> and determined there was no material risk at that time. At </font><font style="font-family:inherit;font-size:10pt;">December 31, 2017</font><font style="font-family:inherit;font-size:10pt;">, the fair values of the net assets (liabilities) we had with each of the counterparties with respect to all of our commodity derivative transactions are listed in the table below: </font></div><div style="line-height:120%;font-size:10pt;"><div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;width:100%;border-collapse:collapse;text-align:left;"><tr><td colspan="4" rowspan="1"></td></tr><tr><td style="width:84%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:14%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;font-weight:bold;">December 31, 2017</font></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="text-align:center;font-size:8pt;"><font style="font-family:inherit;font-size:8pt;font-weight:bold;">(In millions)</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Canadian Imperial Bank of Commerce</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">0.7</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Bank of America Merrill Lynch</font></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(2.5</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Bank of Montreal</font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(5.3</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td></tr><tr><td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Total assets (liabilities)</font></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(7.1</font></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td></tr></table></div><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></div>
CY2017	us-gaap	Use Of Estimates UseOfEstimates	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-indent:30px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The preparation of financial statements in conformity with generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.</font></div></div>

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2017 Q4 Form 10-K Financial Statement

#000079894918000008 Filed on February 27, 2018

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$UNTC UNIT CORP Stock $untc

2017 Q4 Form 10-K Financial Statement

#000079894918000008 Filed on February 27, 2018

Income Statement

Balance Sheet

Cashflow Statement

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$UNTC
UNIT CORP Stock $untc