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Valuation and Qualifying Accounts and Reserves | 12 Months Ended
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Dec. 31, 2012
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] | SCHEDULE II MARTEN TRANSPORT, LTD. Valuation and Qualifying Accounts and Reserves (In thousands)
Description |  | Balance at Beginning of Year |  |  | Charged to Costs and Expenses |  |  | Deductions |  |  | Balance at End of Year |
Insurance and claims accruals: |  |  |  |  |  |  |  |  |  |  |  |
Year ended December 31, 2012 |  | $ | 13,042 |  |  | $ | 32,548 |  |  | $ | (31,752 | )(1) |  | $ | 13,838 |
Year ended December 31, 2011 |  |  | 17,653 |  |  |  | 27,675 |  |  |  | (32,286 | )(1) |  |  | 13,042 |
Year ended December 31, 2010 |  |  | 19,222 |  |  |  | 24,892 |  |  |  | (26,461 | )(1) |  |  | 17,653 |
Allowance for doubtful accounts: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Year ended December 31, 2012 |  |  | 470 |  |  |  | — |  |  |  | (136 | )(2) |  |  | 334 |
Year ended December 31, 2011 |  |  | 170 |  |  |  | 544 |  |  |  | (244 | )(2) |  |  | 470 |
Year ended December 31, 2010 |  |  | 245 |  |  |  | (21 | ) |  |  | (54 | )(2) |  |  | 170 |
(1) | Claims payments
(2) | Write-off of bad debts, net of recoveries

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- Definition The entire disclosure for any allowance and reserve accounts (their beginning and ending balances, as well as a reconciliation by type of activity during the period). Alternatively, disclosure of the required information may be within the footnotes to the financial statements or a supplemental schedule to the financial statements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 09 -Article 12 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e24092-122690 + Details
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Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration