Note 12 - Deferred Compensation Plan (Details Textual)	Dec. 31, 2016 shares
Deferred Compensation Plan Number Of Common Shares Credited To Account Balances	96,310

Deferred compensation plan number of common shares credited to account balances.

No definition available.

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