XML 42 R31.htm IDEA: XBRL DOCUMENT
v3.22.4

Schedule II - Valuation and Qualifying Accounts and Reserves (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2022
Notes Tables |
Schedule of Valuation and Qualifying Accounts [Table Text Block] |
|  | Balance at |  |  | Charged to |  |  |  |  |  |  |  |  |  |
|  | Beginning of |  |  | Costs and |  |  |  |  |  |  |  | Balance at |
Description |  | Year |  |  | Expenses |  |  | Deductions |  |  |  | End of Year |
Insurance and claims accruals: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Year ended December 31, 2022 |  | $ | 42,014 |  |  | $ | 67,790 |  |  | $ | (64,057 | ) | (1) |  | $ | 45,747 |
Year ended December 31, 2021 |  |  | 39,595 |  |  |  | 55,342 |  |  |  | (52,923 | ) | (1) |  |  | 42,014 |
Year ended December 31, 2020 |  |  | 31,729 |  |  |  | 64,276 |  |  |  | (56,410 | ) | (1) |  |  | 39,595 |
Allowance for doubtful accounts: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Year ended December 31, 2022 |  |  | 348 |  |  |  | 350 |  |  |  | (198 | ) | (2) |  |  | 500 |
Year ended December 31, 2021 |  |  | 348 |  |  |  | - |  |  |  | - |  | (2) |  |  | 348 |
Year ended December 31, 2020 |  |  | 382 |  |  |  | 220 |  |  |  | (254 | ) | (2) |  |  | 348 |

X
- Definition Tabular disclosure of valuation and qualifying accounts and reserves. + References No definition available. + Details
Name: | mrtn_ScheduleOfValuationAndQualifyingAccountsTableTextBlock
Namespace Prefix: | mrtn_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_TableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration