Represents the dividend limit as a percentage of net income as required by the terms of the credit facility.

No definition available.

Name:	mrtn_LineOfCreditFacilityDividendRestrictionsPercentageOfNetIncomeLimit
Namespace Prefix:	mrtn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	mrtn_Note8DividendsDetailsLineItems
Namespace Prefix:	mrtn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash outflow in the form of capital distributions and dividends to common shareholders, preferred shareholders and noncontrolling interests.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

+ Details

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

- Details

Name:	us-gaap_DividendsAxis=mrtn_PaidQuarterlyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=mrtn_SpecialDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 8 - Dividends (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended			3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012
Note 8 - Dividends (Details) [Line Items]
Payments of Dividends (in Dollars)	$ 3.3us-gaap_PaymentsOfDividends	$ 2.8us-gaap_PaymentsOfDividends	$ 18.7us-gaap_PaymentsOfDividends
Line of Credit Facility, Dividend Restrictions, Percentage of Net Income Limit	25.00%
Paid Quarterly [Member]
Note 8 - Dividends (Details) [Line Items]
Common Stock, Dividends, Per Share, Declared				$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.017	$ 0.017	$ 0.017	$ 0.017	$ 0.017	$ 0.013
Special Dividend [Member]
Note 8 - Dividends (Details) [Line Items]
Common Stock, Dividends, Per Share, Declared												$ 0.50