CAPITAL CONSTRUCTION FUND - Investment maturity (Details) $ in Millions	Sep. 30, 2024 USD ($) item
CAPITAL CONSTRUCTION FUND
Remainder of 2024	$ 47.8
2025	189.8
2026	166.9
2027	52.2
Total CCF investments	456.7
Remainder of 2024	47.8
2025	190.5
2026	168.6
2027	53.0
Total CCF investments	$ 459.9
Number of vessels under agreements for construction \| item	3

No definition available.

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Namespace Prefix:	matx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Cost of capital construction fund investments maturing maturing in third fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestments
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cost of capital construction fund investments maturing in remainder of current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsCostMaturitiesRemainderOfFiscalYear
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cost of capital construction fund investments maturing maturing in next fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsCostMaturitiesYearOne
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cost of capital construction fund investments maturing maturing in second fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsCostMaturitiesYearThree
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cost of capital construction fund investments maturing maturing in second fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsCostMaturitiesYearTwo
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of investments made under capital construction fund.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsFairValue
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of capital construction fund investments maturing in remainder of current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsFairValueMaturitiesRemainderOfFiscalYear
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of capital construction fund investments maturing maturing in next fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsFairValueMaturitiesYearOne
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of capital construction fund investments maturing maturing in third fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsFairValueMaturitiesYearThree
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of capital construction fund investments maturing maturing in second fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	matx_CapitalConstructionFundInvestmentsFairValueMaturitiesYearTwo
Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of vessels under agreements for construction.

+ References

No definition available.

+ Details

Name:	matx_NumberOfVesselsUnderAgreementForConstruction
Namespace Prefix:	matx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant