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Retirement Plans - Fair Value of Entity's Plan Assets (Detail) - Pension Plan - USD ($) $ in Thousands | Dec. 25, 2020 | Mar. 27, 2020 | Mar. 29, 2019 | Mar. 29, 2018
--- | --- | --- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | $ 7,089 | $ 5,579 | $ 5,171 | $ 5,350
Government securities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1,826 | 1,260 | 805 |
Unit investment trust fund |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1,155 | 897 | 747 |
Loans |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 562 | 756 | 760 |
Bonds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1,193 | 1,094 | 1,160 |
Stocks and other investments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 2,353 | 1,572 | 1,699 |
Level 1 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 3,031 | 2,467 | 2,150 |
Level 1 | Government securities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1,826 | 1,260 | 805 |
Level 1 | Stocks and other investments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1,205 | 1,207 | 1,345 |
Level 2 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 2,349 | 1,992 | 1,908 |
Level 2 | Unit investment trust fund |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1,155 | 897 | 747 |
Level 2 | Bonds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1,193 | 1,094 | 1,160 |
Level 2 | Stocks and other investments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1 | 1 | 1 |
Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 1,709 | 1,120 | 1,113 |
Level 3 | Loans |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | 562 | 756 | 760 | $ 600
Level 3 | Stocks and other investments |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Assets of non-U.S. defined benefit plan | $ 1,147 | $ 364 | $ 353 |

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