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Accounts Receivable, Contract Assets, and Contract Liabilities - Change in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jul. 25, 2020 | Jul. 27, 2019 | Jul. 25, 2020 | Jul. 27, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Allowance for doubtful accounts at beginning of period | $ 5,166 | $ 1,372 | $ 4,582 | $ 17,702
Provision for bad debt (recovery) | 119 | (202) | 236 | (10,514)
Amounts recovered (charged) against the allowance | (3,680) | (246) | (3,684) | (6,264)
Allowance for doubtful accounts at end of period | 1,605 | 924 | 1,605 | 924
Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Allowance for doubtful accounts at beginning of period |  |  | 471 |
Allowance for doubtful accounts at end of period | $ 0 | $ 0 | 0 | $ 0
Windstream Corporation |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Allowance for doubtful accounts at beginning of period |  |  | $ 16,800 |

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