3.19.2 html 352 408 1 false 87 0 false 9 false false R1.htm 0001000 - Document - Document And Entity Information Sheet http://www.altamesa.net/role/DocumentAndEntityInformation Document And Entity Information Cover 1 false false R2.htm 1001000 - Statement - Condensed Consolidated Balance Sheets (Unaudited) Sheet http://www.altamesa.net/role/CondensedConsolidatedBalanceSheetsUnaudited Condensed Consolidated Balance Sheets (Unaudited) Statements 2 false false R3.htm 1001000 - Statement - Condensed Consolidated Statements of Operations (Unaudited) Sheet http://www.altamesa.net/role/CondensedConsolidatedStatementsOfOperationsUnaudited Condensed Consolidated Statements of Operations (Unaudited) Statements 3 false false R4.htm 1001001 - Statement - Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) Sheet http://www.altamesa.net/role/CondensedConsolidatedBalanceSheetsUnauditedParenthetical Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) Statements 4 false false R5.htm 1002000 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited) Sheet http://www.altamesa.net/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited Condensed Consolidated Statements of Cash Flows (Unaudited) Statements 5 false false R6.htm 1003000 - Statement - Condensed Consolidated Statement Of Changes In Stockholders' Equity (Unaudited) (Successor) Sheet http://www.altamesa.net/role/CondensedConsolidatedStatementOfChangesInStockholdersEquityUnauditedSuccessor Condensed Consolidated Statement Of Changes In Stockholders' Equity (Unaudited) (Successor) Statements 6 false false R7.htm 1004000 - Statement - Condensed Consolidated Statements of Changes In Partners' Capital (Unaudited) Sheet http://www.altamesa.net/role/CondensedConsolidatedStatementsOfChangesInPartnersCapitalUnaudited Condensed Consolidated Statements of Changes In Partners' Capital (Unaudited) Statements 7 false false R8.htm 2101100 - Disclosure - Description of Business Sheet http://www.altamesa.net/role/DescriptionOfBusiness Description of Business Notes 8 false false R9.htm 2101100 - Disclosure - Summary of Significant Accounting Policies Sheet http://www.altamesa.net/role/SummaryOfSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 9 false false R10.htm 2102100 - Disclosure - Adoption of ASU No. 2016-02, Leases Sheet http://www.altamesa.net/role/AdoptionOfAsuNo201602Leases Adoption of ASU No. 2016-02, Leases Notes 10 false false R11.htm 2103100 - Disclosure - Supplemental Cash Flow Information Sheet http://www.altamesa.net/role/SupplementalCashFlowInformation Supplemental Cash Flow Information Notes 11 false false R12.htm 2104100 - Disclosure - Receivables Sheet http://www.altamesa.net/role/Receivables Receivables Notes 12 false false R13.htm 2105100 - Disclosure - Property And Equipment Sheet http://www.altamesa.net/role/PropertyAndEquipment Property And Equipment Notes 13 false false R14.htm 2106100 - Disclosure - Discontinued Operations Sheet http://www.altamesa.net/role/DiscontinuedOperations Discontinued Operations Notes 14 false false R15.htm 2107100 - Disclosure - Derivatives Sheet http://www.altamesa.net/role/Derivatives Derivatives Notes 15 false false R16.htm 2108100 - Disclosure - Accounts Payable And Accrued Liabilities Sheet http://www.altamesa.net/role/AccountsPayableAndAccruedLiabilities Accounts Payable And Accrued Liabilities Notes 16 false false R17.htm 2109100 - Disclosure - Asset Retirement Obligations Sheet http://www.altamesa.net/role/AssetRetirementObligations Asset Retirement Obligations Notes 17 false false R18.htm 2109100 - Disclosure - Debt Sheet http://www.altamesa.net/role/Debt Debt Notes 18 false false R19.htm 2110100 - Disclosure - Commitments And Contingencies Sheet http://www.altamesa.net/role/CommitmentsAndContingencies Commitments And Contingencies Notes 19 false false R20.htm 2111100 - Disclosure - Significant Concentrations Sheet http://www.altamesa.net/role/SignificantConcentrations Significant Concentrations Notes 20 false false R21.htm 2113100 - Disclosure - Equity-Based Compensation (Successor) Sheet http://www.altamesa.net/role/EquityBasedCompensationSuccessor Equity-Based Compensation (Successor) Notes 21 false false R22.htm 2114100 - Disclosure - Related Party Transactions Sheet http://www.altamesa.net/role/RelatedPartyTransactions Related Party Transactions Notes 22 false false R23.htm 2116100 - Disclosure - Business Segment Information Sheet http://www.altamesa.net/role/BusinessSegmentInformation Business Segment Information Notes 23 false false R24.htm 2201201 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://www.altamesa.net/role/SummaryOfSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://www.altamesa.net/role/SummaryOfSignificantAccountingPolicies 24 false false R25.htm 2302301 - Disclosure - Adoption of ASU No. 2016-02, Leases (Tables) Sheet http://www.altamesa.net/role/AdoptionOfAsuNo201602LeasesTables Adoption of ASU No. 2016-02, Leases (Tables) Tables http://www.altamesa.net/role/AdoptionOfAsuNo201602Leases 25 false false R26.htm 2303301 - Disclosure - Supplemental Cash Flow Information (Tables) Sheet http://www.altamesa.net/role/SupplementalCashFlowInformationTables Supplemental Cash Flow Information (Tables) Tables http://www.altamesa.net/role/SupplementalCashFlowInformation 26 false false R27.htm 2304301 - Disclosure - Receivables (Tables) Sheet http://www.altamesa.net/role/ReceivablesTables Receivables (Tables) Tables http://www.altamesa.net/role/Receivables 27 false false R28.htm 2305301 - Disclosure - Property And Equipment (Tables) Sheet http://www.altamesa.net/role/PropertyAndEquipmentTables Property And Equipment (Tables) Tables http://www.altamesa.net/role/PropertyAndEquipment 28 false false R29.htm 2306301 - Disclosure - Discontinued Operations (Tables) Sheet http://www.altamesa.net/role/DiscontinuedOperationsTables Discontinued Operations (Tables) Tables http://www.altamesa.net/role/DiscontinuedOperations 29 false false R30.htm 2307301 - Disclosure - Derivatives (Tables) Sheet http://www.altamesa.net/role/DerivativesTables Derivatives (Tables) Tables http://www.altamesa.net/role/Derivatives 30 false false R31.htm 2308301 - Disclosure - Accounts Payable And Accrued Liabilities (Tables) Sheet http://www.altamesa.net/role/AccountsPayableAndAccruedLiabilitiesTables Accounts Payable And Accrued Liabilities (Tables) Tables http://www.altamesa.net/role/AccountsPayableAndAccruedLiabilities 31 false false R32.htm 2309301 - Disclosure - Asset Retirement Obligations (Tables) Sheet http://www.altamesa.net/role/AssetRetirementObligationsTables Asset Retirement Obligations (Tables) Tables http://www.altamesa.net/role/AssetRetirementObligations 32 false false R33.htm 2309301 - Disclosure - Debt (Tables) Sheet http://www.altamesa.net/role/DebtTables Debt (Tables) Tables http://www.altamesa.net/role/Debt 33 false false R34.htm 2311301 - Disclosure - Significant Concentrations (Tables) Sheet http://www.altamesa.net/role/SignificantConcentrationsTables Significant Concentrations (Tables) Tables http://www.altamesa.net/role/SignificantConcentrations 34 false false R35.htm 2313301 - Disclosure - Equity-Based Compensation (Successor) (Tables) Sheet http://www.altamesa.net/role/EquityBasedCompensationSuccessorTables Equity-Based Compensation (Successor) (Tables) Tables http://www.altamesa.net/role/EquityBasedCompensationSuccessor 35 false false R36.htm 2316301 - Disclosure - Business Segment Information (Tables) Sheet http://www.altamesa.net/role/BusinessSegmentInformationTables Business Segment Information (Tables) Tables http://www.altamesa.net/role/BusinessSegmentInformation 36 false false R37.htm 2401402 - Disclosure - Summary of Significant Accounting Policies (Details) Sheet http://www.altamesa.net/role/SummaryOfSignificantAccountingPoliciesDetails Summary of Significant Accounting Policies (Details) Details http://www.altamesa.net/role/SummaryOfSignificantAccountingPoliciesPolicies 37 false false R38.htm 2402402 - Disclosure - Adoption of ASU No. 2016-02, Leases (Narrative) (Details) Sheet http://www.altamesa.net/role/AdoptionOfAsuNo201602LeasesNarrativeDetails Adoption of ASU No. 2016-02, Leases (Narrative) (Details) Details http://www.altamesa.net/role/AdoptionOfAsuNo201602LeasesTables 38 false false R39.htm 2402403 - Disclosure - Adoption of ASU No. 2016-02, Leases (Components of Lease Expense) (Details) Sheet http://www.altamesa.net/role/AdoptionOfAsuNo201602LeasesComponentsOfLeaseExpenseDetails Adoption of ASU No. 2016-02, Leases (Components of Lease Expense) (Details) Details http://www.altamesa.net/role/AdoptionOfAsuNo201602LeasesTables 39 false false R40.htm 2402404 - Disclosure - Adoption of ASU No. 2016-02, Leases (Maturities of Operating Lease Liabilities) (Details) Sheet http://www.altamesa.net/role/AdoptionOfAsuNo201602LeasesMaturitiesOfOperatingLeaseLiabilitiesDetails Adoption of ASU No. 2016-02, Leases (Maturities of Operating Lease Liabilities) (Details) Details http://www.altamesa.net/role/AdoptionOfAsuNo201602LeasesTables 40 false false R41.htm 2403402 - Disclosure - Supplemental Cash Flow Information (Supplemental Disclosures To The Consolidated Statements Of Cash Flows) (Details) Sheet http://www.altamesa.net/role/SupplementalCashFlowInformationSupplementalDisclosuresToConsolidatedStatementsOfCashFlowsDetails Supplemental Cash Flow Information (Supplemental Disclosures To The Consolidated Statements Of Cash Flows) (Details) Details http://www.altamesa.net/role/SupplementalCashFlowInformationTables 41 false false R42.htm 2403403 - Disclosure - Supplemental Cash Flow Information (Cash and Restricted Cash) (Details) Sheet http://www.altamesa.net/role/SupplementalCashFlowInformationCashAndRestrictedCashDetails Supplemental Cash Flow Information (Cash and Restricted Cash) (Details) Details http://www.altamesa.net/role/SupplementalCashFlowInformationTables 42 false false R43.htm 2404402 - Disclosure - Receivables (Schedule of Accounts Receivable) (Details) Sheet http://www.altamesa.net/role/ReceivablesScheduleOfAccountsReceivableDetails Receivables (Schedule of Accounts Receivable) (Details) Details http://www.altamesa.net/role/ReceivablesTables 43 false false R44.htm 2404403 - Disclosure - Receivables (Schedule of Related Party Receivables) (Details) Sheet http://www.altamesa.net/role/ReceivablesScheduleOfRelatedPartyReceivablesDetails Receivables (Schedule of Related Party Receivables) (Details) Details http://www.altamesa.net/role/ReceivablesTables 44 false false R45.htm 2404404 - Disclosure - Receivables Receivables (Narrative) (Details) Sheet http://www.altamesa.net/role/ReceivablesReceivablesNarrativeDetails Receivables Receivables (Narrative) (Details) Details 45 false false R46.htm 2405402 - Disclosure - Property And Equipment (Summary Of Property And Equipment) (Details) Sheet http://www.altamesa.net/role/PropertyAndEquipmentSummaryOfPropertyAndEquipmentDetails Property And Equipment (Summary Of Property And Equipment) (Details) Details http://www.altamesa.net/role/PropertyAndEquipmentTables 46 false false R47.htm 2405403 - Disclosure - Property And Equipment (Depreciation and Depletion Expense) (Details) Sheet http://www.altamesa.net/role/PropertyAndEquipmentDepreciationAndDepletionExpenseDetails Property And Equipment (Depreciation and Depletion Expense) (Details) Details http://www.altamesa.net/role/PropertyAndEquipmentTables 47 false false R48.htm 2406402 - Disclosure - Discontinued Operations (Narrative) (Details) Sheet http://www.altamesa.net/role/DiscontinuedOperationsNarrativeDetails Discontinued Operations (Narrative) (Details) Details http://www.altamesa.net/role/DiscontinuedOperationsTables 48 false false R49.htm 2406403 - Disclosure - Discontinued Operations (Schedule Of Operations And Other Items Reclassified In Discontinued Operations) (Details) Sheet http://www.altamesa.net/role/DiscontinuedOperationsScheduleOfOperationsAndOtherItemsReclassifiedInDiscontinuedOperationsDetails Discontinued Operations (Schedule Of Operations And Other Items Reclassified In Discontinued Operations) (Details) Details http://www.altamesa.net/role/DiscontinuedOperationsTables 49 false false R50.htm 2406404 - Disclosure - Discontinued Operations (Total Operating And Investing Cash Flows Of Discontinued Operations) (Details) Sheet http://www.altamesa.net/role/DiscontinuedOperationsTotalOperatingAndInvestingCashFlowsOfDiscontinuedOperationsDetails Discontinued Operations (Total Operating And Investing Cash Flows Of Discontinued Operations) (Details) Details http://www.altamesa.net/role/DiscontinuedOperationsTables 50 false false R51.htm 2407402 - Disclosure - Derivatives (Fair Values Of Derivative Contracts) (Details) Sheet http://www.altamesa.net/role/DerivativesFairValuesOfDerivativeContractsDetails Derivatives (Fair Values Of Derivative Contracts) (Details) Details http://www.altamesa.net/role/DerivativesTables 51 false false R52.htm 2407403 - Disclosure - Derivatives (Effect Of Derivative Instruments In The Consolidated Statements Of Operations) (Details) Sheet http://www.altamesa.net/role/DerivativesEffectOfDerivativeInstrumentsInConsolidatedStatementsOfOperationsDetails Derivatives (Effect Of Derivative Instruments In The Consolidated Statements Of Operations) (Details) Details http://www.altamesa.net/role/DerivativesTables 52 false false R53.htm 2407404 - Disclosure - Derivatives (Additional Information) (Details) Sheet http://www.altamesa.net/role/DerivativesAdditionalInformationDetails Derivatives (Additional Information) (Details) Details http://www.altamesa.net/role/DerivativesTables 53 false false R54.htm 2407405 - Disclosure - Derivatives (Oil Derivative Contracts) (Details) Sheet http://www.altamesa.net/role/DerivativesOilDerivativeContractsDetails Derivatives (Oil Derivative Contracts) (Details) Details http://www.altamesa.net/role/DerivativesTables 54 false false R55.htm 2407406 - Disclosure - Derivatives (Natural Gas Derivative Contracts) (Details) Sheet http://www.altamesa.net/role/DerivativesNaturalGasDerivativeContractsDetails Derivatives (Natural Gas Derivative Contracts) (Details) Details http://www.altamesa.net/role/DerivativesTables 55 false false R56.htm 2407407 - Disclosure - Derivatives (Basis Swap Derivative Contracts) (Details) Sheet http://www.altamesa.net/role/DerivativesBasisSwapDerivativeContractsDetails Derivatives (Basis Swap Derivative Contracts) (Details) Details http://www.altamesa.net/role/DerivativesTables 56 false false R57.htm 2408402 - Disclosure - Accounts Payable And Accrued Liabilities (Details) Sheet http://www.altamesa.net/role/AccountsPayableAndAccruedLiabilitiesDetails Accounts Payable And Accrued Liabilities (Details) Details http://www.altamesa.net/role/AccountsPayableAndAccruedLiabilitiesTables 57 false false R58.htm 2409402 - Disclosure - Asset Retirement Obligations (Details) Sheet http://www.altamesa.net/role/AssetRetirementObligationsDetails Asset Retirement Obligations (Details) Details http://www.altamesa.net/role/AssetRetirementObligationsTables 58 false false R59.htm 2409402 - Disclosure - Debt (Schedule of Long-Term Debt, Net) (Details) Sheet http://www.altamesa.net/role/DebtScheduleOfLongTermDebtNetDetails Debt (Schedule of Long-Term Debt, Net) (Details) Details http://www.altamesa.net/role/DebtTables 59 false false R60.htm 2409403 - Disclosure - Debt (Narrative) (Details) Sheet http://www.altamesa.net/role/DebtNarrativeDetails Debt (Narrative) (Details) Details http://www.altamesa.net/role/DebtTables 60 false false R61.htm 2409404 - Disclosure - Debt (Summary Of Future Maturities Of Long-Term Debt) (Details) Sheet http://www.altamesa.net/role/DebtSummaryOfFutureMaturitiesOfLongTermDebtDetails Debt (Summary Of Future Maturities Of Long-Term Debt) (Details) Details http://www.altamesa.net/role/DebtTables 61 false false R62.htm 2411402 - Disclosure - Significant Concentrations (Details) Sheet http://www.altamesa.net/role/SignificantConcentrationsDetails Significant Concentrations (Details) Details http://www.altamesa.net/role/SignificantConcentrationsTables 62 false false R63.htm 2413402 - Disclosure - Equity-Based Compensation (Successor) (Stock Compensation Expense) (Details) Sheet http://www.altamesa.net/role/EquityBasedCompensationSuccessorStockCompensationExpenseDetails Equity-Based Compensation (Successor) (Stock Compensation Expense) (Details) Details http://www.altamesa.net/role/EquityBasedCompensationSuccessorTables 63 false false R64.htm 2413403 - Disclosure - Equity-Based Compensation (Successor) (Narrative) (Details) Sheet http://www.altamesa.net/role/EquityBasedCompensationSuccessorNarrativeDetails Equity-Based Compensation (Successor) (Narrative) (Details) Details http://www.altamesa.net/role/EquityBasedCompensationSuccessorTables 64 false false R65.htm 2414401 - Disclosure - Related Party Transactions (Details) Sheet http://www.altamesa.net/role/RelatedPartyTransactionsDetails Related Party Transactions (Details) Details http://www.altamesa.net/role/RelatedPartyTransactions 65 false false R66.htm 2416402 - Disclosure - Business Segment Information (Details) Sheet http://www.altamesa.net/role/BusinessSegmentInformationDetails Business Segment Information (Details) Details http://www.altamesa.net/role/BusinessSegmentInformationTables 66 false false R9999.htm Uncategorized Items - altms-20190331.xml Sheet http://xbrl.sec.gov/role/uncategorizedFacts Uncategorized Items - altms-20190331.xml Cover 67 false false All Reports Book All Reports altms-20190331.xml altms-20190331.xsd altms-20190331_cal.xml altms-20190331_def.xml altms-20190331_lab.xml altms-20190331_pre.xml http://fasb.org/us-gaap/2018-01-31 http://xbrl.sec.gov/dei/2018-01-31 http://fasb.org/srt/2018-01-31 true true