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Concentrations of Credit Risk and Major Customers (Details)	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Concentrations of Credit Risk and Major Customers (Details) [Line Items]
Customers accounting percentage	10.00%
Accounts Receivable [Member]
Concentrations of Credit Risk and Major Customers (Details) [Line Items]
Customers accounting percentage	10.00%	10.00%
Total revenue [Member]
Concentrations of Credit Risk and Major Customers (Details) [Line Items]
Customers accounting percentage	10.00%	10.00%	10.00%

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator), this concept represents the concentration percentage derived from the division.

+ References

No definition available.

+ Details

Name:	hiho_ConcentrationRiskThresholdPercentage
Namespace Prefix:	hiho_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

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- References

No definition available.

+ Details

Name:	hiho_ConcentrationsofCreditRiskandMajorCustomersDetailsLineItems
Namespace Prefix:	hiho_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: