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Represents maximum period for dry-docking.

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No definition available.

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- Definition

Represents minimum period for dry-docking.

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No definition available.

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- Definition

Represents the number of dry-docking inspections to be made within a specified period.

+ References

No definition available.

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- Definition

Represents the number of non-U.S. flag vessels operated by the entity.

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No definition available.

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Represents the number of non-U.S. flag vessels owned by the entity.

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No definition available.

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- Definition

Represents the number of non-U.S. flag vessels under bareboat charter operated by the entity.

+ References

No definition available.

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Represents the number of non-U.S. flag vessels under time charter operated by the entity.

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No definition available.

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- Definition

Represents the period within which number of specified dry-docking inspections to be made.

+ References

No definition available.

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- Definition

Sum of the carrying amounts of deferred costs that are expected to be recognized as a charge against earnings in periods after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

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The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Impairment

-URI http://asc.fasb.org/extlink&oid=6515133

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- Definition

Amount before tax of other than temporary impairment (OTTI) on investment in available-for-sale debt security, recognized in other comprehensive loss, attributable to parent entity.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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SIGNIFICANT ACCOUNTING POLICIES (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 item	Dec. 31, 2013	Dec. 31, 2012
Impairment of Investment
Impairment charges related to investment in Terminal joint venture	$ 0	$ 0	$ 0
Impairment of Vessels and Equipment
Impairment charges of vessels and equipment	0	0
Dry-docking
Number of dry-docking inspections to be made within a specified period	2
Period within which number of specified dry-docking inspections to be made	5 years
Number of non-U.S. flag vessels in operations	4
Number of non-U.S. flag vessels owned	1matx_NumberOfNonUSFlagVesselsOwned
Number of non-U.S. flag vessels under bareboat charter	1
Number of non-U.S. flag vessels under time charter	2
Dry-dock interval, minimum	2 years
Dry-dock interval, maximum	5 years
Deferred dry-docking costs	$ 47.5us-gaap_DeferredCosts	$ 56.9us-gaap_DeferredCosts
Vessels \| Minimum
Depreciation
Useful life	5 years
Vessels \| Maximum
Depreciation
Useful life	40 years
Machinery And Equipment \| Minimum
Depreciation
Useful life	2 years
Machinery And Equipment \| Maximum
Depreciation
Useful life	20 years
Terminal Facilities \| Minimum
Depreciation
Useful life	2 years
Terminal Facilities \| Maximum
Depreciation
Useful life	35 years