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Comprehensive Income (Tables) | 12 Months Ended
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Dec. 31, 2011
Comprehensive Income [Abstract] |
Components Of Comprehensive Income |
|  | Fiscal Year |
|  | 2011 |  |  | 2010 |  |  | 2009 |
Net income attributable to Landstar System, Inc. and subsidiary |  | $ | 113,007 |  |  | $ | 87,514 |  |  | $ | 70,395 |
Unrealized holding gains on available-for-sale investments |  |  | 26 |  |  |  | 312 |  |  |  | 791 |
Income tax expense on unrealized holding gains on available-for-sale investments |  |  | (9 | ) |  |  | (111 | ) |  |  | (279 | )
Net unrealized holding gains on available-for-sale investments |  |  | 17 |  |  |  | 201 |  |  |  | 512 |
Foreign currency translation gains (losses) |  |  | (171 | ) |  |  | 182 |  |  |  | 547 |
Comprehensive income attributable to Landstar System, Inc. and subsidiary |  | $ | 112,853 |  |  | $ | 87,897 |  |  | $ | 71,454 |

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- Definition Tabular disclosure of the components of accumulated other comprehensive income (loss). + References No definition available. + Details
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