Covenant for minimum working capital.

No definition available.

Name:	matx_DebtInstrumentCovenantMinimumWorkingCapital
Namespace Prefix:	matx_
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Balance Type:	debit
Period Type:	instant

- Definition

Debt instrument covenant, long-term debt to net worth.

+ References

No definition available.

+ Details

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- Definition

Debt instrument covenant ratio, maintenance of net worth.

+ References

No definition available.

+ Details

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Namespace Prefix:	matx_
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Balance Type:	na
Period Type:	instant

- Definition

Threshold leverage ratio under the debt instrument covenant.

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold leverage ratio in connection with material acquisition under the debt instrument covenant.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Amount of semi-annual principal payments that the company has to pay after year five since the first year of maturity payment as stated in the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of semi-annual principal payments that the company has to pay in the year one as stated in the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of semi-annual principal payments that the company has to pay in year two to year five since the first year of maturity payment as stated in the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	matx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of vessels committed to securing debt.

+ References

No definition available.

+ Details

Name:	matx_NumberOfVesselsCommittedToSecuringDebt
Namespace Prefix:	matx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the total principal payments made during the annual reporting period.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The average effective interest rate during the reporting period.

+ References

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+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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- Details

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Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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- Details

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- Details

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DEBT - REVOLVING CREDIT FACILITY (Details)			12 Months Ended
DEBT - REVOLVING CREDIT FACILITY (Details)	Mar. 31, 2021 USD ($)	Sep. 14, 2016 USD ($)	Dec. 31, 2021 USD ($) item	Jun. 22, 2020 USD ($)	Apr. 27, 2020 USD ($)
Title XI Notes
Debt
The number of vessels committed to securing debt \| item			2
Revolving Credit Facility
Debt
Maximum borrowing capacity under revolving credit facility	$ 650,000,000
Ratio of debt instrument covenant threshold leverage	3.50
Ratio of debt instrument covenant threshold leverage connection with material acquisition	4.0
Fees paid	$ 2,200,000
Funds available under the revolving credit facility			$ 642,000,000.0
Interest rate during period (as a percent)			1.10%
Standby commercial letters of credit
Debt
Used portion of revolving credit facility			$ 8,000,000.0
The Senior Unsecured Notes (The "Series D Notes")
Debt
Debt issued		$ 200,000,000.0
Debt instrument term		15 years
Maturities of Long-term Debt
Semi-annual principal payments in year 2019		$ 6,000,000.0
Semi-annual principal payments in 2020 to 2023		9,200,000
Semi-annual principal payments in 2024 to 2031		$ 7,150,000
London Interbank Offered Rate (LIBOR) \| Revolving Credit Facility \| Minimum
Debt
Variable rate margin	1.00%
London Interbank Offered Rate (LIBOR) \| Revolving Credit Facility \| Maximum
Debt
Variable rate margin	1.75%
Base rate \| Revolving Credit Facility \| Minimum
Debt
Variable rate margin	0.00%
Base rate \| Revolving Credit Facility \| Maximum
Debt
Variable rate margin	0.75%
MatNav \| Title XI Notes
Debt
Minimum working capital covenant			$ 1
Debt instrument covenant ratio, maintenance of net worth			90.00%
Debt issued				$ 139,600,000	$ 185,900,000
Annual principal payments				$ 3,000,000.0	$ 4,000,000.0
MatNav \| Minimum \| Title XI Notes
Debt
Debt instrument covenant, long-term debt to net worth			2.00%