3.26.1 html 81 232 1 false 32 0 false 7 false false R1.htm 995200090 - Document - Document and Entity Information Sheet http://www.millerind.com/role/DocumentDocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 995200100 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS Sheet http://www.millerind.com/role/StatementCondensedConsolidatedBalanceSheets CONDENSED CONSOLIDATED BALANCE SHEETS Statements 2 false false R3.htm 995200105 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) Sheet http://www.millerind.com/role/StatementCondensedConsolidatedBalanceSheetsParentheticals CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) Statements 3 false false R4.htm 995200200 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF INCOME Sheet http://www.millerind.com/role/StatementCondensedConsolidatedStatementsOfIncome CONDENSED CONSOLIDATED STATEMENTS OF INCOME Statements 4 false false R5.htm 995200300 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME Sheet http://www.millerind.com/role/StatementCondensedConsolidatedStatementsOfComprehensiveIncome CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME Statements 5 false false R6.htm 995200400 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY Sheet http://www.millerind.com/role/StatementCondensedConsolidatedStatementsOfShareholdersEquity CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY Statements 6 false false R7.htm 995200405 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parentheticals) Sheet http://www.millerind.com/role/StatementCondensedConsolidatedStatementsOfShareholdersEquityParentheticals CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parentheticals) Statements 7 false false R8.htm 995200500 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS Sheet http://www.millerind.com/role/StatementCondensedConsolidatedStatementsOfCashFlows CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS Statements 8 false false R9.htm 995210101 - Disclosure - BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES Sheet http://www.millerind.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES Notes 9 false false R10.htm 995210201 - Disclosure - BUSINESS COMBINATIONS Sheet http://www.millerind.com/role/DisclosureBusinessCombinations BUSINESS COMBINATIONS Notes 10 false false R11.htm 995210301 - Disclosure - INVENTORY Sheet http://www.millerind.com/role/DisclosureInventory INVENTORY Notes 11 false false R12.htm 995210401 - Disclosure - PROPERTY, PLANT AND EQUIPMENT Sheet http://www.millerind.com/role/DisclosurePropertyPlantAndEquipment PROPERTY, PLANT AND EQUIPMENT Notes 12 false false R13.htm 995210501 - Disclosure - LONG-TERM OBLIGATIONS Sheet http://www.millerind.com/role/DisclosureLongTermObligations LONG-TERM OBLIGATIONS Notes 13 false false R14.htm 995210601 - Disclosure - INCOME TAXES Sheet http://www.millerind.com/role/DisclosureIncomeTaxes INCOME TAXES Notes 14 false false R15.htm 995210701 - Disclosure - LEASES Sheet http://www.millerind.com/role/DisclosureLeases LEASES Notes 15 false false R16.htm 995210801 - Disclosure - COMMITMENTS AND CONTINGENCIES Sheet http://www.millerind.com/role/DisclosureCommitmentsAndContingencies COMMITMENTS AND CONTINGENCIES Notes 16 false false R17.htm 995210901 - Disclosure - SHAREHOLDERS' EQUITY Sheet http://www.millerind.com/role/DisclosureShareholdersEquity SHAREHOLDERS' EQUITY Notes 17 false false R18.htm 995211001 - Disclosure - REVENUE Sheet http://www.millerind.com/role/DisclosureRevenue REVENUE Notes 18 false false R19.htm 995211101 - Disclosure - EARNINGS PER SHARE Sheet http://www.millerind.com/role/DisclosureEarningsPerShare EARNINGS PER SHARE Notes 19 false false R20.htm 995211201 - Disclosure - SUBSEQUENT EVENTS Sheet http://www.millerind.com/role/DisclosureSubsequentEvents SUBSEQUENT EVENTS Notes 20 false false R21.htm 995410 - Disclosure - Pay vs Performance Disclosure Sheet http://xbrl.sec.gov/ecd/role/PvpDisclosure Pay vs Performance Disclosure Notes 21 false false R22.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 22 false false R23.htm 99920102 - Disclosure - BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies) Sheet http://www.millerind.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPolicies BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies) Policies 23 false false R24.htm 99930103 - Disclosure - BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Tables) Sheet http://www.millerind.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesTables BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Tables) Tables http://www.millerind.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies 24 false false R25.htm 99930203 - Disclosure - BUSINESS COMBINATIONS (Tables) Sheet http://www.millerind.com/role/DisclosureBusinessCombinationsTables BUSINESS COMBINATIONS (Tables) Tables http://www.millerind.com/role/DisclosureBusinessCombinations 25 false false R26.htm 99930303 - Disclosure - INVENTORY (Tables) Sheet http://www.millerind.com/role/DisclosureInventoryTables INVENTORY (Tables) Tables http://www.millerind.com/role/DisclosureInventory 26 false false R27.htm 99930403 - Disclosure - PROPERTY, PLANT AND EQUIPMENT (Tables) Sheet http://www.millerind.com/role/DisclosurePropertyPlantAndEquipmentTables PROPERTY, PLANT AND EQUIPMENT (Tables) Tables http://www.millerind.com/role/DisclosurePropertyPlantAndEquipment 27 false false R28.htm 99930703 - Disclosure - LEASES (Tables) Sheet http://www.millerind.com/role/DisclosureLeasesTables LEASES (Tables) Tables http://www.millerind.com/role/DisclosureLeases 28 false false R29.htm 99930903 - Disclosure - SHAREHOLDERS' EQUITY (Tables) Sheet http://www.millerind.com/role/DisclosureShareholdersEquityTables SHAREHOLDERS' EQUITY (Tables) Tables http://www.millerind.com/role/DisclosureShareholdersEquity 29 false false R30.htm 99931003 - Disclosure - REVENUE (Tables) Sheet http://www.millerind.com/role/DisclosureRevenueTables REVENUE (Tables) Tables http://www.millerind.com/role/DisclosureRevenue 30 false false R31.htm 99931303 - Disclosure - EARNINGS PER SHARE (Tables) Sheet http://www.millerind.com/role/DisclosureEarningsPerShareTables EARNINGS PER SHARE (Tables) Tables http://www.millerind.com/role/DisclosureEarningsPerShare 31 false false R32.htm 99940111 - Disclosure - BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Segment Disclosures (Details) Sheet http://www.millerind.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesSegmentDisclosuresDetails BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Segment Disclosures (Details) Details 32 false false R33.htm 99940201 - Disclosure - BUSINESS COMBINATIONS - Narrative (Details) Sheet http://www.millerind.com/role/DisclosureBusinessCombinationsNarrativeDetails BUSINESS COMBINATIONS - Narrative (Details) Details 33 false false R34.htm 99940202 - Disclosure - BUSINESS COMBINATIONS - Schedule of allocations for net assets acquired (Details) Sheet http://www.millerind.com/role/DisclosureBusinessCombinationsScheduleOfAllocationsForNetAssetsAcquiredDetails BUSINESS COMBINATIONS - Schedule of allocations for net assets acquired (Details) Details 34 false false R35.htm 99940203 - Disclosure - BUSINESS COMBINATIONS - Pro forma summary (Details) Sheet http://www.millerind.com/role/DisclosureBusinessCombinationsProFormaSummaryDetails BUSINESS COMBINATIONS - Pro forma summary (Details) Details 35 false false R36.htm 99940301 - Disclosure - INVENTORY - Schedule of Inventories, Net of Reserves (Details) Sheet http://www.millerind.com/role/DisclosureInventoryScheduleOfInventoriesNetOfReservesDetails INVENTORY - Schedule of Inventories, Net of Reserves (Details) Details 36 false false R37.htm 99940401 - Disclosure - PROPERTY, PLANT AND EQUIPMENT (Details) Sheet http://www.millerind.com/role/DisclosurePropertyPlantAndEquipmentDetails PROPERTY, PLANT AND EQUIPMENT (Details) Details http://www.millerind.com/role/DisclosurePropertyPlantAndEquipmentTables 37 false false R38.htm 99940501 - Disclosure - LONG-TERM OBLIGATIONS (Details) Sheet http://www.millerind.com/role/DisclosureLongTermObligationsDetails LONG-TERM OBLIGATIONS (Details) Details http://www.millerind.com/role/DisclosureLongTermObligations 38 false false R39.htm 99940601 - Disclosure - INCOME TAXES - Narrative (Details) Sheet http://www.millerind.com/role/DisclosureIncomeTaxesNarrativeDetails INCOME TAXES - Narrative (Details) Details 39 false false R40.htm 99940604 - Disclosure - INCOME TAXES - Reconciliation of income taxes (Details) Sheet http://www.millerind.com/role/DisclosureIncomeTaxesReconciliationOfIncomeTaxesDetails INCOME TAXES - Reconciliation of income taxes (Details) Details 40 false false R41.htm 99940606 - Disclosure - INCOME TAXES - Schedule of Income Taxes Paid (Details) Sheet http://www.millerind.com/role/DisclosureIncomeTaxesScheduleOfIncomeTaxesPaidDetails INCOME TAXES - Schedule of Income Taxes Paid (Details) Details 41 false false R42.htm 99940701 - Disclosure - LEASES - Lease cost (Details) Sheet http://www.millerind.com/role/DisclosureLeasesLeaseCostDetails LEASES - Lease cost (Details) Details 42 false false R43.htm 99940702 - Disclosure - LEASES - Schedule of Weighted-average lease term and weighted-average discount rate (Details) Sheet http://www.millerind.com/role/DisclosureLeasesScheduleOfWeightedAverageLeaseTermAndWeightedAverageDiscountRateDetails LEASES - Schedule of Weighted-average lease term and weighted-average discount rate (Details) Details 43 false false R44.htm 99940703 - Disclosure - LEASES - Maturity of Undiscounted Cash flows of operating lease obligations (Details) Sheet http://www.millerind.com/role/DisclosureLeasesMaturityOfUndiscountedCashFlowsOfOperatingLeaseObligationsDetails LEASES - Maturity of Undiscounted Cash flows of operating lease obligations (Details) Details 44 false false R45.htm 99940801 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details) Sheet http://www.millerind.com/role/DisclosureCommitmentsAndContingenciesDetails COMMITMENTS AND CONTINGENCIES (Details) Details http://www.millerind.com/role/DisclosureCommitmentsAndContingencies 45 false false R46.htm 99940901 - Disclosure - SHAREHOLDERS' EQUITY (Details) Sheet http://www.millerind.com/role/DisclosureShareholdersEquityDetails SHAREHOLDERS' EQUITY (Details) Details http://www.millerind.com/role/DisclosureShareholdersEquityTables 46 false false R47.htm 99940902 - Disclosure - STOCK INCENTIVE PLAN - Restricted Stock Units (Details) Sheet http://www.millerind.com/role/DisclosureStockIncentivePlanRestrictedStockUnitsDetails STOCK INCENTIVE PLAN - Restricted Stock Units (Details) Details 47 false false R48.htm 99941001 - Disclosure - REVENUE - Schedule of Disaggregation of Revenue by Geographic Segment (Details) 10Q Sheet http://www.millerind.com/role/DisclosureRevenueScheduleOfDisaggregationOfRevenueByGeographicSegmentDetails10q REVENUE - Schedule of Disaggregation of Revenue by Geographic Segment (Details) 10Q Details 48 false false R49.htm 99941002 - Disclosure - REVENUE - Narrative (Details) Sheet http://www.millerind.com/role/DisclosureRevenueNarrativeDetails REVENUE - Narrative (Details) Details 49 false false R50.htm 99941101 - Disclosure - EARNINGS PER SHARE (Details) Sheet http://www.millerind.com/role/DisclosureEarningsPerShareDetails EARNINGS PER SHARE (Details) Details http://www.millerind.com/role/DisclosureEarningsPerShareTables 50 false false R51.htm 99941201 - Disclosure - SUBSEQUENT EVENTS (Details) Sheet http://www.millerind.com/role/DisclosureSubsequentEventsDetails SUBSEQUENT EVENTS (Details) Details http://www.millerind.com/role/DisclosureSubsequentEvents 51 false false All Reports Book All Reports mlr-20260331.xsd mlr-20260331_cal.xml mlr-20260331_def.xml mlr-20260331_lab.xml mlr-20260331_pre.xml mlr-20260331x10q.htm mlr-20260331x10q001.jpg mlr-20260331x10q003.jpg http://fasb.org/srt/2025 http://fasb.org/us-gaap/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 true true