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Inventories, Net (Details) - USD ($) $ in Thousands | 12 Months Ended
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Mar. 31, 2021 | Mar. 31, 2020 | Mar. 31, 2019
Inventory Disclosure [Abstract] |  |  |
Slow moving inventories | $ 125 | $ 39 | $ 419

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- Definition slow moving inventories during the period. + References No definition available. + Details
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Namespace Prefix: | hiho_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_InventoryDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration