| **Financial Instruments and Commodity Contracts - Narrative (Details) (USD $)** | Apr. 30, 2015                                                                                                                                                                          | Oct. 31, 2014                                                                                                                                                                          | Apr. 30, 2014                           |
|---------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------|
| **Derivative [Line Items]**                                                     |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| Derivative, Amount of Hedged Item                                               | $ 0us-gaap_DerivativeAmountOfHedgedItem                                                                                                                                                |                                                                                                                                                                                   | $ 0us-gaap_DerivativeAmountOfHedgedItem |
| Derivative, Collateral, Obligation to Return Cash                               | 1,000,000us-gaap_DerivativeCollateralObligationToReturnCash                                                                                                                            | 0us-gaap_DerivativeCollateralObligationToReturnCash                                                                                                                                    |                                    |
| Exposure to Credit Risk                                                         | 1,000,000nav_ExposureToCreditRisk                                                                                                                                                      |                                                                                                                                                                                   |                                    |
| Interest Rate Contract [Member]                                                 |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| **Derivative [Line Items]**                                                     |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| Derivative, Notional Amount                                                     | 0invest_DerivativeNotionalAmount/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateContractMember                                                                             | 27,000,000invest_DerivativeNotionalAmount/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateContractMember                                                                    |                                    |
| Diesel Fuel Forward Contracts [Member] | Commodity Contract [Member]            |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| **Derivative [Line Items]**                                                     |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| Derivative, Notional Amount                                                     | 17,000,000invest_DerivativeNotionalAmount/ us-gaap_DerivativeByNatureAxis= nav_DieselFuelForwardContractsMember/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_CommodityContractMember | 24,000,000invest_DerivativeNotionalAmount/ us-gaap_DerivativeByNatureAxis= nav_DieselFuelForwardContractsMember/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_CommodityContractMember |                                    |
| Steel Forward Contracts [Member] | Commodity Contract [Member]                  |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| **Derivative [Line Items]**                                                     |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| Derivative, Notional Amount                                                     | 11,000,000invest_DerivativeNotionalAmount/ us-gaap_DerivativeByNatureAxis= nav_SteelForwardContractsMember/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_CommodityContractMember      | 23,000,000invest_DerivativeNotionalAmount/ us-gaap_DerivativeByNatureAxis= nav_SteelForwardContractsMember/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_CommodityContractMember      |                                    |
| Mexican Financial Services [Member] | Asset-backed Securities [Member]          |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| **Derivative [Line Items]**                                                     |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| Derivative, Notional Amount                                                     | 118,000,000invest_DerivativeNotionalAmount/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_AssetBackedSecuritiesMember/ dei_EntityByLocationAxis= nav_MexicanFinancialServicesMember    |                                                                                                                                                                                   |                                    |
| Mexican Financial Services [Member] | Interest Rate Cap [Member]                |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| **Derivative [Line Items]**                                                     |                                                                                                                                                                                   |                                                                                                                                                                                   |                                    |
| Derivative, Notional Amount                                                     |                                                                                                                                                                                   | $ 134,000,000invest_DerivativeNotionalAmount/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ dei_EntityByLocationAxis= nav_MexicanFinancialServicesMember        |                                    |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B
+ Details**Name:**invest_DerivativeNotionalAmount**Namespace Prefix:**invest_**Data Type:**xbrli:monetaryItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Exposure to Credit Risk
+ References
No definition available.
+ Details**Name:**nav_ExposureToCreditRisk**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of the hedged item as of the balance sheet date related to the derivative. For example, the hedged balance on a debt instrument.
+ References
No definition available.
+ Details**Name:**us-gaap_DerivativeAmountOfHedgedItem**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226016-175313Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41678-113959
+ Details**Name:**us-gaap_DerivativeCollateralObligationToReturnCash**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DerivativeLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**dei_EntityByLocationAxis=nav_MexicanFinancialServicesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DerivativeByNatureAxis=nav_DieselFuelForwardContractsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                      |
|--------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DerivativeByNatureAxis=nav_SteelForwardContractsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |