Line of credit facility dividend restrictions percentage of net income limit.

No definition available.

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Balance Type:	na
Period Type:	instant

- Definition

The maximum amount for a waiver to pay for dividends as part of a line of credit facility.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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=120397183&loc=d3e187085-122770

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=124098289&loc=d3e6935-107765

+ Details

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

- Definition

Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3291-108585

+ Details

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

- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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Note 6 - Dividends (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended		9 Months Ended
	Aug. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Nov. 30, 2020
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 0.54	$ 0.04			$ 0.62	$ 0.093
Payments of Ordinary Dividends, Common Stock				$ 6,600		$ 6,626	$ 7,705
Dividends Payable, Current		$ 44,789				44,789		$ 0
Line Of Credit Facility Dividend Restrictions Percentage Of Net Income Limit									25.00%
Line of Credit Facility, Waiver to Pay Dividends, Maximum		$ 80,000				$ 80,000			$ 60,000
Paid Quarterly [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.04		$ 0.04	$ 0.04	$ 0.027
Special Dividend [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.50