XML 49 R36.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Schedule II - Valuation and Qualifying Accounts and Reserves (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2018
Notes Tables |
Valuation Allowances and Reserves [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, 2018 |  | $ | 26,177 |  |  | $ | 56,122 |  |  | $ | (54,196 | ) | (1) | $ | 28,103 |
Year ended December 31, 2017 |  |  | 19,440 |  |  |  | 53,609 |  |  |  | (46,872 | ) | (1) |  | 26,177 |
Year ended December 31, 2016 |  |  | 16,235 |  |  |  | 49,614 |  |  |  | (46,409 | ) | (1) |  | 19,440 |
Allowance for doubtful accounts: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Year ended December 31, 2018 |  |  | 300 |  |  |  | 163 |  |  |  | (115 | ) | (2) |  | 348 |
Year ended December 31, 2017 |  |  | 275 |  |  |  | 33 |  |  |  | (8 | ) | (2) |  | 300 |
Year ended December 31, 2016 |  |  | 305 |  |  |  | 88 |  |  |  | (118 | ) | (2) |  | 275 |

X
- Definition Tabular disclosure of a schedule of allowance and reserve accounts where the valuation and qualifying accounts are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs. + References No definition available. + Details
Name: | mrtn_ValuationAllowancesAndReservesTableTextBlock
Namespace Prefix: | mrtn_
Data Type: | nonnum: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