3.19.1 html 235 281 1 false 75 0 false 11 false false R1.htm 100000 - Document - Document and Entity Information Sheet http://ampcopgh.com/20190331/taxonomy/role/DocumentDocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 100010 - Statement - Condensed Consolidated Balance Sheets (Unaudited) Sheet http://ampcopgh.com/20190331/taxonomy/role/StatementCondensedConsolidatedBalanceSheetsUnaudited Condensed Consolidated Balance Sheets (Unaudited) Statements 2 false false R3.htm 100020 - Statement - Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) Sheet http://ampcopgh.com/20190331/taxonomy/role/StatementCondensedConsolidatedBalanceSheetsUnauditedParenthetical Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) Statements 3 false false R4.htm 100030 - Statement - Condensed Consolidated Statements of Operations (Unaudited) Sheet http://ampcopgh.com/20190331/taxonomy/role/StatementCondensedConsolidatedStatementsOfOperationsUnaudited Condensed Consolidated Statements of Operations (Unaudited) Statements 4 false false R5.htm 100040 - Statement - Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) Sheet http://ampcopgh.com/20190331/taxonomy/role/StatementCondensedConsolidatedStatementsOfComprehensiveIncomeLossUnaudited Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) Statements 5 false false R6.htm 100050 - Statement - Condensed Consolidated Statements of Shareholders' Equity (Unaudited) Sheet http://ampcopgh.com/20190331/taxonomy/role/StatementCondensedConsolidatedStatementsOfShareholdersEquityUnaudited Condensed Consolidated Statements of Shareholders' Equity (Unaudited) Statements 6 false false R7.htm 100060 - Statement - Condensed Consolidated Statements of Shareholders' Equity (Unaudited) (Parenthetical) Sheet http://ampcopgh.com/20190331/taxonomy/role/StatementCondensedConsolidatedStatementsOfShareholdersEquityUnauditedParenthetical Condensed Consolidated Statements of Shareholders' Equity (Unaudited) (Parenthetical) Statements 7 false false R8.htm 100070 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited) Sheet http://ampcopgh.com/20190331/taxonomy/role/StatementCondensedConsolidatedStatementsOfCashFlowsUnaudited Condensed Consolidated Statements of Cash Flows (Unaudited) Statements 8 false false R9.htm 100080 - Disclosure - Unaudited Condensed Consolidated Financial Statements Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureUnauditedCondensedConsolidatedFinancialStatements Unaudited Condensed Consolidated Financial Statements Notes 9 false false R10.htm 100090 - Disclosure - Discontinued Operations and Disposition Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDiscontinuedOperationsAndDisposition Discontinued Operations and Disposition Notes 10 false false R11.htm 100100 - Disclosure - Inventories Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureInventories Inventories Notes 11 false false R12.htm 100110 - Disclosure - Property, Plant and Equipment Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePropertyPlantAndEquipment Property, Plant and Equipment Notes 12 false false R13.htm 100120 - Disclosure - Intangible Assets Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureIntangibleAssets Intangible Assets Notes 13 false false R14.htm 100130 - Disclosure - Other Current Liabilities Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureOtherCurrentLiabilities Other Current Liabilities Notes 14 false false R15.htm 100140 - Disclosure - Borrowing Arrangements Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureBorrowingArrangements Borrowing Arrangements Notes 15 false false R16.htm 100150 - Disclosure - Pension and Other Postretirement Benefits Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefits Pension and Other Postretirement Benefits Notes 16 false false R17.htm 100160 - Disclosure - Commitments and Contingent Liabilities Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingentLiabilities Commitments and Contingent Liabilities Notes 17 false false R18.htm 100170 - Disclosure - Accumulated Other Comprehensive Loss Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLoss Accumulated Other Comprehensive Loss Notes 18 false false R19.htm 100180 - Disclosure - Derivative Instruments Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDerivativeInstruments Derivative Instruments Notes 19 false false R20.htm 100190 - Disclosure - Fair Value Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureFairValue Fair Value Notes 20 false false R21.htm 100200 - Disclosure - Revenue Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureRevenue Revenue Notes 21 false false R22.htm 100210 - Disclosure - Stock-Based Compensation Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureStockBasedCompensation Stock-Based Compensation Notes 22 false false R23.htm 100220 - Disclosure - Litigation Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureLitigation Litigation Notes 23 false false R24.htm 100230 - Disclosure - Environmental Matters Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureEnvironmentalMatters Environmental Matters Notes 24 false false R25.htm 100240 - Disclosure - Business Segments Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureBusinessSegments Business Segments Notes 25 false false R26.htm 100250 - Disclosure - Subsequent Events Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureSubsequentEvents Subsequent Events Notes 26 false false R27.htm 100260 - Disclosure - Unaudited Condensed Consolidated Financial Statements (Policies) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureUnauditedCondensedConsolidatedFinancialStatementsPolicies Unaudited Condensed Consolidated Financial Statements (Policies) Policies 27 false false R28.htm 100270 - Disclosure - Discontinued Operations and Disposition (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDiscontinuedOperationsAndDispositionTables Discontinued Operations and Disposition (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureDiscontinuedOperationsAndDisposition 28 false false R29.htm 100280 - Disclosure - Inventories (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureInventoriesTables Inventories (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureInventories 29 false false R30.htm 100290 - Disclosure - Property, Plant and Equipment (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePropertyPlantAndEquipmentTables Property, Plant and Equipment (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosurePropertyPlantAndEquipment 30 false false R31.htm 100300 - Disclosure - Intangible Assets (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureIntangibleAssetsTables Intangible Assets (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureIntangibleAssets 31 false false R32.htm 100310 - Disclosure - Other Current Liabilities (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureOtherCurrentLiabilitiesTables Other Current Liabilities (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureOtherCurrentLiabilities 32 false false R33.htm 100320 - Disclosure - Borrowing Arrangements (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureBorrowingArrangementsTables Borrowing Arrangements (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureBorrowingArrangements 33 false false R34.htm 100330 - Disclosure - Pension and Other Postretirement Benefits (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsTables Pension and Other Postretirement Benefits (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefits 34 false false R35.htm 100340 - Disclosure - Accumulated Other Comprehensive Loss (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossTables Accumulated Other Comprehensive Loss (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLoss 35 false false R36.htm 100350 - Disclosure - Derivative Instruments (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDerivativeInstrumentsTables Derivative Instruments (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureDerivativeInstruments 36 false false R37.htm 100360 - Disclosure - Fair Value (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureFairValueTables Fair Value (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureFairValue 37 false false R38.htm 100370 - Disclosure - Revenue (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureRevenueTables Revenue (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureRevenue 38 false false R39.htm 100380 - Disclosure - Litigation (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureLitigationTables Litigation (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureLitigation 39 false false R40.htm 100390 - Disclosure - Business Segments (Tables) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureBusinessSegmentsTables Business Segments (Tables) Tables http://ampcopgh.com/20190331/taxonomy/role/DisclosureBusinessSegments 40 false false R41.htm 100400 - Disclosure - Unaudited Condensed Consolidated Financial Statements - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureUnauditedCondensedConsolidatedFinancialStatementsAdditionalInformationDetail Unaudited Condensed Consolidated Financial Statements - Additional Information (Detail) Details 41 false false R42.htm 100410 - Disclosure - Discontinued Operations and Disposition - Summary of Assets and Liabilities of ASW (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDiscontinuedOperationsAndDispositionSummaryOfAssetsAndLiabilitiesOfASWDetail Discontinued Operations and Disposition - Summary of Assets and Liabilities of ASW (Detail) Details 42 false false R43.htm 100420 - Disclosure - Discontinued Operations and Disposition - Summary of Major Classes of ASW's Loss from Discontinued Operations, Net of Tax in the Condensed Consolidated Statements of Operations (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDiscontinuedOperationsAndDispositionSummaryOfMajorClassesOfASWSLossFromDiscontinuedOperationsNetOfTaxInCondensedConsolidatedStatementsOfOperationsDetail Discontinued Operations and Disposition - Summary of Major Classes of ASW's Loss from Discontinued Operations, Net of Tax in the Condensed Consolidated Statements of Operations (Detail) Details 43 false false R44.htm 100430 - Disclosure - Discontinued Operations and Disposition - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDiscontinuedOperationsAndDispositionAdditionalInformationDetail Discontinued Operations and Disposition - Additional Information (Detail) Details 44 false false R45.htm 100440 - Disclosure - Inventories - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureInventoriesAdditionalInformationDetail Inventories - Additional Information (Detail) Details 45 false false R46.htm 100450 - Disclosure - Inventories - Schedule of Inventories (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureInventoriesScheduleOfInventoriesDetail Inventories - Schedule of Inventories (Detail) Details 46 false false R47.htm 100460 - Disclosure - Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePropertyPlantAndEquipmentScheduleOfPropertyPlantAndEquipmentDetail Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) Details 47 false false R48.htm 100470 - Disclosure - Property, Plant and Equipment - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePropertyPlantAndEquipmentAdditionalInformationDetail Property, Plant and Equipment - Additional Information (Detail) Details 48 false false R49.htm 100480 - Disclosure - Intangible Assets - Schedule of Intangible Assets (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureIntangibleAssetsScheduleOfIntangibleAssetsDetail Intangible Assets - Schedule of Intangible Assets (Detail) Details 49 false false R50.htm 100490 - Disclosure - Intangible Assets - Summary of Changes in Intangible Assets (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureIntangibleAssetsSummaryOfChangesInIntangibleAssetsDetail Intangible Assets - Summary of Changes in Intangible Assets (Detail) Details 50 false false R51.htm 100500 - Disclosure - Other Current Liabilities - Schedule of Other Current Liabilities (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureOtherCurrentLiabilitiesScheduleOfOtherCurrentLiabilitiesDetail Other Current Liabilities - Schedule of Other Current Liabilities (Detail) Details 51 false false R52.htm 100510 - Disclosure - Other Current Liabilities - Schedule of Changes in Liability for Product Warranty Claims (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureOtherCurrentLiabilitiesScheduleOfChangesInLiabilityForProductWarrantyClaimsDetail Other Current Liabilities - Schedule of Changes in Liability for Product Warranty Claims (Detail) Details 52 false false R53.htm 100520 - Disclosure - Other Current Liabilities - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureOtherCurrentLiabilitiesAdditionalInformationDetail Other Current Liabilities - Additional Information (Detail) Details 53 false false R54.htm 100530 - Disclosure - Other Current Liabilities - Schedule of Change in Customer Deposits (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureOtherCurrentLiabilitiesScheduleOfChangeInCustomerDepositsDetail Other Current Liabilities - Schedule of Change in Customer Deposits (Detail) Details 54 false false R55.htm 100540 - Disclosure - Borrowing Arrangements - Schedule of Outstanding Borrowings (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureBorrowingArrangementsScheduleOfOutstandingBorrowingsDetail Borrowing Arrangements - Schedule of Outstanding Borrowings (Detail) Details 55 false false R56.htm 100560 - Disclosure - Borrowing Arrangements - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureBorrowingArrangementsAdditionalInformationDetail Borrowing Arrangements - Additional Information (Detail) Details 56 false false R57.htm 100570 - Disclosure - Pension and Other Postretirement Benefits - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsAdditionalInformationDetail Pension and Other Postretirement Benefits - Additional Information (Detail) Details 57 false false R58.htm 100580 - Disclosure - Pension and Other Postretirement Benefits - Contributions for Pension and Other Postretirement Benefits (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsContributionsForPensionAndOtherPostretirementBenefitsDetail Pension and Other Postretirement Benefits - Contributions for Pension and Other Postretirement Benefits (Detail) Details 58 false false R59.htm 100590 - Disclosure - Pension and Other Postretirement Benefits - Net Periodic Pension and Other Postretirement Benefit Costs (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsNetPeriodicPensionAndOtherPostretirementBenefitCostsDetail Pension and Other Postretirement Benefits - Net Periodic Pension and Other Postretirement Benefit Costs (Detail) Details 59 false false R60.htm 100600 - Disclosure - Commitments and Contingent Liabilities - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingentLiabilitiesAdditionalInformationDetail Commitments and Contingent Liabilities - Additional Information (Detail) Details 60 false false R61.htm 100610 - Disclosure - Accumulated Other Comprehensive Loss - Net Change and Ending Balances for Various Components of Accumulated Other Comprehensive Loss (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossNetChangeAndEndingBalancesForVariousComponentsOfAccumulatedOtherComprehensiveLossDetail Accumulated Other Comprehensive Loss - Net Change and Ending Balances for Various Components of Accumulated Other Comprehensive Loss (Detail) Details 61 false false R62.htm 100620 - Disclosure - Accumulated Other Comprehensive Loss - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossAdditionalInformationDetail Accumulated Other Comprehensive Loss - Additional Information (Detail) Details 62 false false R63.htm 100630 - Disclosure - Accumulated Other Comprehensive Loss - Line Items Affected on Condensed Consolidated Statements of Operations for Components Reclassified from Accumulated Other Comprehensive Loss (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossLineItemsAffectedOnCondensedConsolidatedStatementsOfOperationsForComponentsReclassifiedFromAccumulatedOtherComprehensiveLossDetail Accumulated Other Comprehensive Loss - Line Items Affected on Condensed Consolidated Statements of Operations for Components Reclassified from Accumulated Other Comprehensive Loss (Detail) Details 63 false false R64.htm 100640 - Disclosure - Derivative Instruments - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDerivativeInstrumentsAdditionalInformationDetail Derivative Instruments - Additional Information (Detail) Details 64 false false R65.htm 100650 - Disclosure - Derivative Instruments - Location and Fair Value of Foreign Currency Sales Contracts Recorded on Condensed Consolidated Balance Sheets (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDerivativeInstrumentsLocationAndFairValueOfForeignCurrencySalesContractsRecordedOnCondensedConsolidatedBalanceSheetsDetail Derivative Instruments - Location and Fair Value of Foreign Currency Sales Contracts Recorded on Condensed Consolidated Balance Sheets (Detail) Details 65 false false R66.htm 100660 - Disclosure - Derivative Instruments - Summary of Amount Recognized as and Reclassified from Accumulated Other Comprehensive Income (Loss) (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDerivativeInstrumentsSummaryOfAmountRecognizedAsAndReclassifiedFromAccumulatedOtherComprehensiveIncomeLossDetail Derivative Instruments - Summary of Amount Recognized as and Reclassified from Accumulated Other Comprehensive Income (Loss) (Detail) Details 66 false false R67.htm 100670 - Disclosure - Derivative Instruments - Summary of Change in Fair Value Reclassified or Expected to be Reclassified from Accumulated Other Comprehensive Loss to Earnings (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureDerivativeInstrumentsSummaryOfChangeInFairValueReclassifiedOrExpectedToBeReclassifiedFromAccumulatedOtherComprehensiveLossToEarningsDetail Derivative Instruments - Summary of Change in Fair Value Reclassified or Expected to be Reclassified from Accumulated Other Comprehensive Loss to Earnings (Detail) Details 67 false false R68.htm 100680 - Disclosure - Fair Value - Fair Value of Financial Assets and Liabilities (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureFairValueFairValueOfFinancialAssetsAndLiabilitiesDetail Fair Value - Fair Value of Financial Assets and Liabilities (Detail) Details 68 false false R69.htm 100690 - Disclosure - Revenue - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureRevenueAdditionalInformationDetail Revenue - Additional Information (Detail) Details 69 false false R70.htm 100700 - Disclosure - Revenue - Net Sales and (Loss) Income from Continuing Operations before Income Taxes (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureRevenueNetSalesAndLossIncomeFromContinuingOperationsBeforeIncomeTaxesDetail Revenue - Net Sales and (Loss) Income from Continuing Operations before Income Taxes (Detail) Details 70 false false R71.htm 100710 - Disclosure - Stock-Based Compensation - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureStockBasedCompensationAdditionalInformationDetail Stock-Based Compensation - Additional Information (Detail) Details 71 false false R72.htm 100720 - Disclosure - Litigation - Schedule of Loss Contingencies by Contingency (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureLitigationScheduleOfLossContingenciesByContingencyDetail Litigation - Schedule of Loss Contingencies by Contingency (Detail) Details 72 false false R73.htm 100730 - Disclosure - Litigation - Schedule of Loss Contingencies by Contingency (Parenthetical) (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureLitigationScheduleOfLossContingenciesByContingencyParentheticalDetail Litigation - Schedule of Loss Contingencies by Contingency (Parenthetical) (Detail) Details 73 false false R74.htm 100740 - Disclosure - Litigation - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureLitigationAdditionalInformationDetail Litigation - Additional Information (Detail) Details 74 false false R75.htm 100750 - Disclosure - Litigation - Summary of Activity in Asbestos Insurance Recoveries (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureLitigationSummaryOfActivityInAsbestosInsuranceRecoveriesDetail Litigation - Summary of Activity in Asbestos Insurance Recoveries (Detail) Details 75 false false R76.htm 100760 - Disclosure - Environmental Matters - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureEnvironmentalMattersAdditionalInformationDetail Environmental Matters - Additional Information (Detail) Details 76 false false R77.htm 100770 - Disclosure - Business Segments - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureBusinessSegmentsAdditionalInformationDetail Business Segments - Additional Information (Detail) Details 77 false false R78.htm 100780 - Disclosure - Business Segments - Business Segment Net Sales and (Loss) Income from Continuing Operations before Income Taxes (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureBusinessSegmentsBusinessSegmentNetSalesAndLossIncomeFromContinuingOperationsBeforeIncomeTaxesDetail Business Segments - Business Segment Net Sales and (Loss) Income from Continuing Operations before Income Taxes (Detail) Details 78 false false R79.htm 100790 - Disclosure - Subsequent Events - Additional Information (Detail) Sheet http://ampcopgh.com/20190331/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetail Subsequent Events - Additional Information (Detail) Details 79 false false All Reports Book All Reports ap-20190331.xml ap-20190331.xsd ap-20190331_cal.xml ap-20190331_def.xml ap-20190331_lab.xml ap-20190331_pre.xml http://fasb.org/srt/2018-01-31 http://xbrl.sec.gov/country/2017-01-31 http://fasb.org/us-gaap/2018-01-31 http://xbrl.sec.gov/dei/2018-01-31 http://xbrl.sec.gov/invest/2013-01-31 http://xbrl.sec.gov/stpr/2018-01-31 true true