| Line | 
           Label | 
           Object Class | 
           Period Type | 
           Balance | 
           Report ElementName | 
        
        
           | 1 | 
           Financial Reporting Ontology | 
           [Network] | 
           *  | 
           *  | 
           http://www.xbrlsite.com/2015/fro/us-gaap/xbrl/Ontology/role/FinancialReportingOntology | 
        
        
           | 2 | 
           Thing | 
           Abstract  | 
            | 
            | 
           fro:Thing | 
        
        
           | 3 | 
           Business Report | 
           Abstract  | 
            | 
            | 
           fro:BusinessReport | 
        
        
           | 4 | 
           Financial Report | 
           Abstract  | 
            | 
            | 
           fro:FinancialReport | 
        
        
           | 5 | 
           Submission | 
           Abstract  | 
            | 
            | 
           fro:Submission | 
        
        
           | 6 | 
           Economic Entity | 
           Abstract  | 
            | 
            | 
           fro:EconomicEntity | 
        
        
           | 7 | 
           Reporting Unit | 
           Abstract  | 
            | 
            | 
           fro:ReportingUnit | 
        
        
           | 8 | 
           Business Segment | 
           Abstract  | 
            | 
            | 
           fro:BusinessSegment | 
        
        
           | 9 | 
           Geographic Area | 
           Abstract  | 
            | 
            | 
           fro:GeographicArea | 
        
        
           | 10 | 
           Asset Group | 
           Abstract  | 
            | 
            | 
           fro:AssetGroup | 
        
        
           | 11 | 
           Disposal Group | 
           Abstract  | 
            | 
            | 
           fro:DisposalGroup | 
        
        
           | 12 | 
           Subsidiary | 
           Abstract  | 
            | 
            | 
           fro:Subsidiary | 
        
        
           | 13 | 
           Operating Segment | 
           Abstract  | 
            | 
            | 
           fro:OperatingSegment | 
        
        
           | 14 | 
           Reportable Segment | 
           Abstract  | 
            | 
            | 
           fro:ReportableSegment | 
        
        
           | 15 | 
           Business Unit | 
           Abstract  | 
            | 
            | 
           fro:BusinessUnit | 
        
        
           | 16 | 
           Reporting Scheme | 
           Abstract  | 
            | 
            | 
           fro:ReportingScheme | 
        
        
           | 17 | 
           US GAAP | 
           Abstract  | 
            | 
            | 
           fro:USGAAP | 
        
        
           | 18 | 
           IFRS | 
           Abstract  | 
            | 
            | 
           fro:IFRS | 
        
        
           | 19 | 
           Income Tax Basis | 
           Abstract  | 
            | 
            | 
           fro:IncomeTaxBasis | 
        
        
           | 20 | 
           Other Comprehensive Basis of Accounting | 
           Abstract  | 
            | 
            | 
           fro:OtherComprehensiveBasisOfAccounting | 
        
        
           | 21 | 
           Elements of Financial Statement | 
           Abstract  | 
            | 
            | 
           fro:ElementsOfFinancialStatements | 
        
        
           | 22 | 
           Assets | 
           Abstract  | 
            | 
            | 
           fro:Assets | 
        
        
           | 23 | 
           Liabilities | 
           Abstract  | 
            | 
            | 
           fro:Liabilities | 
        
        
           | 24 | 
           Equity | 
           Abstract  | 
            | 
            | 
           fro:Equity | 
        
        
           | 25 | 
           Investments by Owners | 
           Abstract  | 
            | 
            | 
           fro:InvestmentsByOwners | 
        
        
           | 26 | 
           Distributions to Owners | 
           Abstract  | 
            | 
            | 
           fro:DistributionsToOwners | 
        
        
           | 27 | 
           Revenues | 
           Abstract  | 
            | 
            | 
           fro:Revenues | 
        
        
           | 28 | 
           Expenses | 
           Abstract  | 
            | 
            | 
           fro:Expenses | 
        
        
           | 29 | 
           Gains | 
           Abstract  | 
            | 
            | 
           fro:Gains | 
        
        
           | 30 | 
           Losses | 
           Abstract  | 
            | 
            | 
           fro:Losses | 
        
        
           | 31 | 
           Comprehensive Income | 
           Abstract  | 
            | 
            | 
           fro:ComprehensiveIncome | 
        
        
           | 32 | 
           Elements of Financial Statement of Economic Entity | 
           Abstract  | 
            | 
            | 
           fro:ElementsOfFinancialStatementsOfEconomicEntity | 
        
        
           | 33 | 
           Statement of Financial Position (Balance sheet) | 
           Abstract  | 
            | 
            | 
           fro:StatementOfFinancialPosition | 
        
        
           | 34 | 
           Statement of Earnings (Income statement) | 
           Abstract  | 
            | 
            | 
           fro:StatementOfEarnings | 
        
        
           | 35 | 
           Statement of Comprehensive Income | 
           Abstract  | 
            | 
            | 
           fro:StatementOfComprehensiveIncome | 
        
        
           | 36 | 
           Statement of Cash Flows | 
           Abstract  | 
            | 
            | 
           fro:StatementOfCashFlows | 
        
        
           | 37 | 
           Statement of Changes in Equity | 
           Abstract  | 
            | 
            | 
           fro:StatementOfChangesInEquity | 
        
        
           | 38 | 
           Affects on Economic Entity During Period | 
           Abstract  | 
            | 
            | 
           fro:AffectsOnEconomicEntityDuringPeriod | 
        
        
           | 39 | 
           Event | 
           Abstract  | 
            | 
            | 
           fro:Event | 
        
        
           | 40 | 
           Transaction | 
           Abstract  | 
            | 
            | 
           fro:Transaction | 
        
        
           | 41 | 
           Circumstance | 
           Abstract  | 
            | 
            | 
           fro:Circumstance | 
        
        
           | 42 | 
           Entity Legal Form | 
           Abstract  | 
            | 
            | 
           fro:EntityLegalForm | 
        
        
           | 43 | 
           Partnership | 
           Abstract  | 
            | 
            | 
           fro:Partnership | 
        
        
           | 44 | 
           Limited Liability Partnership | 
           Abstract  | 
            | 
            | 
           fro:LimitedLiabilityPartnership | 
        
        
           | 45 | 
           Sole Proprietor | 
           Abstract  | 
            | 
            | 
           fro:SoleProprietor | 
        
        
           | 46 | 
           Corporation | 
           Abstract  | 
            | 
            | 
           fro:Corporation | 
        
        
           | 47 | 
           Limited Liability Corporation | 
           Abstract  | 
            | 
            | 
           fro:LimitedLiabilityCorporation | 
        
        
           | 48 | 
           Financial Report Component | 
           Abstract  | 
            | 
            | 
           fro:FinancialReportComponent | 
        
        
           | 49 | 
           Primary Financial Statement | 
           Abstract  | 
            | 
            | 
           fro:PrimaryFinancialStatement | 
        
        
           | 50 | 
           Parenthetical Comments | 
           Abstract  | 
            | 
            | 
           fro:ParentheticalComments | 
        
        
           | 51 | 
           Disclosure | 
           Abstract  | 
            | 
            | 
           fro:Disclosure | 
        
        
           | 52 | 
           Supplementary Information | 
           Abstract  | 
            | 
            | 
           fro:SupplementaryInformation | 
        
        
           | 53 | 
           Entity Information | 
           Abstract  | 
            | 
            | 
           fro:EntityInformation | 
        
        
           | 54 | 
           Document Information | 
           Abstract  | 
            | 
            | 
           fro:DocumentInformation | 
        
        
           | 55 | 
           Exemplar | 
           Abstract  | 
            | 
            | 
           fro:Exemplar | 
        
        
           | 56 | 
           Prototype | 
           Abstract  | 
            | 
            | 
           fro:Prototype | 
        
        
           | 57 | 
           Topic (Disclosure topic) | 
           Abstract  | 
            | 
            | 
           fro:Topic | 
        
        
           | 58 | 
           Report Element Category | 
           Abstract  | 
            | 
            | 
           fro:ReportElementCategory | 
        
        
           | 59 | 
           Table | 
           Abstract  | 
            | 
            | 
           fro:Table | 
        
        
           | 60 | 
           Concept | 
           Abstract  | 
            | 
            | 
           fro:Concept | 
        
        
           | 61 | 
           Abstract | 
           Abstract  | 
            | 
            | 
           fro:Abstract | 
        
        
           | 62 | 
           Line Items | 
           LineItems  | 
            | 
            | 
           fro:LineItems | 
        
        
           | 63 | 
           Axis | 
           Abstract  | 
            | 
            | 
           fro:Axis | 
        
        
           | 64 | 
           Network | 
           Abstract  | 
            | 
            | 
           fro:Network | 
        
        
           | 65 | 
           Member | 
           Abstract  | 
            | 
            | 
           fro:Member | 
        
        
           | 66 | 
           Characteristic | 
           Abstract  | 
            | 
            | 
           fro:Characteristic | 
        
        
           | 67 | 
           Reporting Entity | 
           Abstract  | 
            | 
            | 
           fro:ReportingEntity | 
        
        
           | 68 | 
           Legal Entity | 
           Abstract  | 
            | 
            | 
           fro:LegalEntity | 
        
        
           | 69 | 
           Parent Holding Company | 
           Abstract  | 
            | 
            | 
           fro:ParentHoldingCompany | 
        
        
           | 70 | 
           Consolidated Entity | 
           Abstract  | 
            | 
            | 
           fro:ConsolidatedEntity | 
        
        
           | 71 | 
           Reporting Scenario | 
           Abstract  | 
            | 
            | 
           fro:ReportingScenario | 
        
        
           | 72 | 
           Business Segment | 
           Abstract  | 
            | 
            | 
           fro:BusinessSegment | 
        
        
           | 73 | 
           Operating Segment | 
           Abstract  | 
            | 
            | 
           fro:OperatingSegment | 
        
        
           | 74 | 
           Geographic Area | 
           Abstract  | 
            | 
            | 
           fro:GeographicArea | 
        
        
           | 75 | 
           Report Date | 
           Abstract  | 
            | 
            | 
           fro:ReportDate | 
        
        
           | 76 | 
           Fiscal Period | 
           Abstract  | 
            | 
            | 
           fro:FiscalPeriod | 
        
        
           | 77 | 
           Calendar Period | 
           Abstract  | 
            | 
            | 
           fro:CalendarPeriod | 
        
        
           | 78 | 
           Instrument | 
           Abstract  | 
            | 
            | 
           fro:Instrument | 
        
        
           | 79 | 
           Range | 
           Abstract  | 
            | 
            | 
           fro:Range | 
        
        
           | 80 | 
           Line Item | 
           Abstract  | 
            | 
            | 
           fro:LineItem | 
        
        
           | 81 | 
           Member Aggregation Pattern | 
           Abstract  | 
            | 
            | 
           fro:MemberAggregationPattern | 
        
        
           | 82 | 
           Partial Set | 
           Abstract  | 
            | 
            | 
           fro:PartialSet | 
        
        
           | 83 | 
           Complete Flat Set | 
           Abstract  | 
            | 
            | 
           fro:CompleteFlatSet | 
        
        
           | 84 | 
           Complete Hierarchical Set | 
           Abstract  | 
            | 
            | 
           fro:CompleteHierarchicalSet | 
        
        
           | 85 | 
           Complete Complex Set | 
           Abstract  | 
            | 
            | 
           fro:CompleteComplexSet | 
        
        
           | 86 | 
           Whole Part Relation Pattern | 
           Abstract  | 
            | 
            | 
           fro:WholePartRelationPattern | 
        
        
           | 87 | 
           Component-Intregal Object | 
           Abstract  | 
            | 
            | 
           fro:ComponentIntregalObject | 
        
        
           | 88 | 
           Member-Collection | 
           Abstract  | 
            | 
            | 
           fro:MemberCollection | 
        
        
           | 89 | 
           Portion-Mass | 
           Abstract  | 
            | 
            | 
           fro:PortionMass | 
        
        
           | 90 | 
           Feature-Activity | 
           Abstract  | 
            | 
            | 
           fro:FeatureActivity | 
        
        
           | 91 | 
           Stuff-Object | 
           Abstract  | 
            | 
            | 
           fro:StuffObject | 
        
        
           | 92 | 
           Place-Area | 
           Abstract  | 
            | 
            | 
           fro:PlaceArea | 
        
        
           | 93 | 
           Computation Pattern | 
           Abstract  | 
            | 
            | 
           fro:ComputationPattern | 
        
        
           | 94 | 
           Roll Up | 
           Abstract  | 
            | 
            | 
           fro:RollUp | 
        
        
           | 95 | 
           Roll Forward | 
           Abstract  | 
            | 
            | 
           fro:RollForward | 
        
        
           | 96 | 
           Hierarchy | 
           Abstract  | 
            | 
            | 
           fro:Hierarchy | 
        
        
           | 97 | 
           Adjustment | 
           Abstract  | 
            | 
            | 
           fro:Adjustment | 
        
        
           | 98 | 
           Variance | 
           Abstract  | 
            | 
            | 
           fro:Variance | 
        
        
           | 99 | 
           Complex Computation | 
           Abstract  | 
            | 
            | 
           fro:ComplexComputation | 
        
        
           | 100 | 
           Text Block | 
           Abstract  | 
            | 
            | 
           fro:TextBlock | 
        
        
           | 101 | 
           Level 1 Text Block (Note) | 
           Abstract  | 
            | 
            | 
           fro:Level1TextBlock | 
        
        
           | 102 | 
           Level 2 Text Block (Policy) | 
           Abstract  | 
            | 
            | 
           fro:Level2TextBlock | 
        
        
           | 103 | 
           Level 2 Text Block (Policy) | 
           Abstract  | 
            | 
            | 
           fro:Level2TextBlock | 
        
        
           | 104 | 
           General Relation Pattern | 
           Abstract  | 
            | 
            | 
           fro:GeneralRelationPattern | 
        
        
           | 105 | 
           Full-Has Part | 
           Abstract  | 
            | 
            | 
           fro:FullHasPart | 
        
        
           | 106 | 
           Class-Subclass | 
           Abstract  | 
            | 
            | 
           fro:ClassSubclass | 
        
        
           | 107 | 
           Class-Equivalent Class | 
           Abstract  | 
            | 
            | 
           fro:ClassEquivalentClass | 
        
        
           | 108 | 
           Table-Equivalent Text Block | 
           Abstract  | 
            | 
            | 
           fro:TableEquivalentTextBlock | 
        
        
           | 109 | 
           Thing-Has Role | 
           Abstract  | 
            | 
            | 
           fro:ThingHasRole | 
        
        
           | 110 | 
           Part-Part of | 
           Abstract  | 
            | 
            | 
           fro:PartPartOf | 
        
        
           | 111 | 
           Verification Rule | 
           Abstract  | 
            | 
            | 
           fro:VerificationRule | 
        
        
           | 112 | 
           Business Rule | 
           Abstract  | 
            | 
            | 
           fro:BusinessRule | 
        
        
           | 113 | 
           Business Rule Pattern | 
           Abstract  | 
            | 
            | 
           fro:BusinessRulePattern | 
        
        
           | 114 | 
           Greater Than Or Equal To Zero | 
           Abstract  | 
            | 
            | 
           fro:GreaterThanOrEqualToZero | 
        
        
           | 115 | 
           Variance | 
           Abstract  | 
            | 
            | 
           fro:Variance | 
        
        
           | 116 | 
           Adjustment | 
           Abstract  | 
            | 
            | 
           fro:Adjustment | 
        
        
           | 117 | 
           Roll Up | 
           Abstract  | 
            | 
            | 
           fro:RollUp | 
        
        
           | 118 | 
           Roll Forward | 
           Abstract  | 
            | 
            | 
           fro:RollForward | 
        
        
           | 119 | 
           Greater Than | 
           Abstract  | 
            | 
            | 
           fro:GreaterThan | 
        
        
           | 120 | 
           Less Than | 
           Abstract  | 
            | 
            | 
           fro:LessThan | 
        
        
           | 121 | 
           Exists | 
           Abstract  | 
            | 
            | 
           fro:Exists | 
        
        
           | 122 | 
           Co Exists | 
           Abstract  | 
            | 
            | 
           fro:CoExists | 
        
        
           | 123 | 
           Equal To | 
           Abstract  | 
            | 
            | 
           fro:EqualTo | 
        
        
           | 124 | 
           Member Aggregation | 
           Abstract  | 
            | 
            | 
           fro:MemberAggregation | 
        
        
           | 125 | 
           Key Financial Ratio | 
           Abstract  | 
            | 
            | 
           fro:KeyFinancialRatio | 
        
        
           | 126 | 
           Domain Rule | 
           Abstract  | 
            | 
            | 
           fro:DomainRule | 
        
        
           | 127 | 
           Industry Specific Rule | 
           Abstract  | 
            | 
            | 
           fro:IndustrySpecificRule | 
        
        
           | 128 | 
           Reporting Entity Rule | 
           Abstract  | 
            | 
            | 
           fro:ReportingEntityRule | 
        
        
           | 129 | 
           Fundamental Concept Skeleton Rule | 
           Abstract  | 
            | 
            | 
           fro:FundamentalConceptSkeletonRule | 
        
        
           | 130 | 
           Peer Consistency Rule | 
           Abstract  | 
            | 
            | 
           fro:PeerConsistencyRule | 
        
        
           | 131 | 
           Prior Period Consistency Rule | 
           Abstract  | 
            | 
            | 
           fro:PriorPeriodConsistencyRule | 
        
        
           | 132 | 
           Reporting System Specific Rule | 
           Abstract  | 
            | 
            | 
           fro:ReportingSystemSpecificRule | 
        
        
           | 133 | 
           Report Level Model Structure Rule | 
           Abstract  | 
            | 
            | 
           fro:ReportLevelModelStructureRule | 
        
        
           | 134 | 
           XBRL Technical Syntax Rule | 
           Abstract  | 
            | 
            | 
           fro:XBRLTechnicalSyntaxRule | 
        
        
           | 135 | 
           Extension Properties | 
           Abstract  | 
            | 
            | 
           fro:ExtensionProperties | 
        
        
           | 136 | 
           Definition of New Subclass Allowed | 
           Abstract  | 
            | 
            | 
           fro:DefinitionOfNewSubclassAllowed | 
        
        
           | 137 | 
           Replace Redefine Allowed | 
           Abstract  | 
            | 
            | 
           fro:ReplaceRedefineAllowed | 
        
        
           | 138 | 
           Extension Disallowed | 
           Abstract  | 
            | 
            | 
           fro:ExtensionDisallowed | 
        
        
           | 139 | 
           Report Frame | 
           Abstract  | 
            | 
            | 
           fro:ReportFrame |