Note 11 - Business Segments - Operating Revenue and Operating Income by Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Operating Revenue	$ 161,287us-gaap_Revenues	$ 159,409us-gaap_Revenues
Operating Income	17,311us-gaap_OperatingIncomeLoss	8,640us-gaap_OperatingIncomeLoss
Total operating income before gain on disposition of facility	13,599	8,640
Revenue, Net of Fuel Surcharge [Member] \| Truckload [Member]
Operating Revenue	86,811	86,802
Revenue, Net of Fuel Surcharge [Member] \| Dedicated [Member]
Operating Revenue	19,863	10,728
Revenue, Net of Fuel Surcharge [Member] \| Intermodal [Member]
Operating Revenue	17,019	18,354
Fuel Surcharge Revenue [Member] \| Truckload [Member]
Operating Revenue	14,590	23,712
Fuel Surcharge Revenue [Member] \| Dedicated [Member]
Operating Revenue	2,591	2,822
Fuel Surcharge Revenue [Member] \| Intermodal [Member]
Operating Revenue	3,373	5,336
Truckload [Member]
Operating Revenue	101,401	110,514
Operating Income	9,602	6,178
Dedicated [Member]
Operating Revenue	22,454	13,550
Operating Income	2,004	1,322
Intermodal [Member]
Operating Revenue	20,392	23,690
Operating Income	1,251	483
Brokerage [Member]
Operating Revenue	17,040	11,655
Operating Income	742	657
Facility [Member]
Gain on disposition of facility	$ 3,712

Represents the operating income or loss before the gain or loss on the disposition of the facility.

No definition available.

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Namespace Prefix:	mrtn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2443-110228

+ Details

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

- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_OperatingIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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- Details

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Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=mrtn_DedicatedMember
Namespace Prefix:
Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

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