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ORGANIZATION AND OPERATIONS OF THE COMPANY - Accounting for Contracts (Details) | 12 Months Ended
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Dec. 27, 2019 USD ($) segment | Dec. 28, 2018 USD ($) | Dec. 29, 2017 USD ($)
Accounting for Contracts |  |  |
Number of reportable segments | segment | 2 |  |
Costs of contract revenue |  |  |
Payroll taxes, bonuses and employee benefit costs for all Company personnel | $ 66,303,000 | $ 45,248,000 | $ 36,534,000
Facilities costs | 8,568,000 | 5,600,000 | $ 4,624,000
Revenue of the entity recorded in which it acts solely in the capacity of an agent | 0 |  |
Costs recorded for costs to the entity in which it acts solely in the capacity of an agent | $ 0 |  |
Maximum |  |  |
Costs of contract revenue |  |  |
Percent of revenue (as a percent) | 3.00% |  |
Minimum |  |  |
Costs of contract revenue |  |  |
Percent of revenue (as a percent) | 2.00% |  |
Accounts receivable |  |  |
Costs of contract revenue |  |  |
Retained accounts receivable | $ 5,400,000 | $ 6,700,000 |
Cost of Sales |  |  |
Costs of contract revenue |  |  |
Payroll taxes, bonuses and employee benefit costs for all Company personnel | 0 |  |
Facilities costs | $ 0 |  |

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