Note 6 - Dividends	6 Months Ended
Jun. 30, 2023
Notes to Financial Statements
Dividends [Text Block]	(6) Dividends In 2010, we announced that our Board of Directors approved a regular cash dividend program to our stockholders, subject to approval each quarter. Quarterly cash dividends of $0.06 per share of common stock were paid in each of the first two quarters of both 2023 and 2022, and totaled $9.8 million in each of the six-month periods.

Disclosure of information related to dividends paid during the period.

No definition available.

Name:	mrtn_DividendsTextBlock
Namespace Prefix:	mrtn_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration