Note 10 - Deferred Compensation Plan (Detail)	Dec. 31, 2012
Deferred Compensation Plan, Number of Common Shares Credited to Account Balances	35,040.2

Number of common shares credit to account balances within the deferred compensation plan as of the reported date.

No definition available.

Name:	mrtn_DeferredCompensationPlanNumberOfCommonSharesCreditedToAccountBalances
Namespace Prefix:	mrtn_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant