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Acquisitions and Dispositions (Narrative) (Details) - USD ($) $ in Thousands |  |  |  |  | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Jun. 28, 2024 | Jun. 01, 2023 | Oct. 01, 2022 | Feb. 01, 2022 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Sep. 12, 2024
Schedule of Business Dispositions, by Dispositions [Line Items] |  |  |  |  |  |  |  |
Gain on sale of business |  |  |  |  | $ 0 | $ 18,965 | $ 225,832 |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Goodwill, Acquired During Period |  |  |  |  | 114,589 |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |
Equity method investments |  |  |  |  | $ 862,500 | $ 605,900 |  |
Educational Partners International [Member] |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |
Equity method investment, ownership percentage |  |  |  |  |  |  |  | 68.00%
Equity method investments |  |  |  |  |  |  |  | $ 167,700
Volante [Member] |  |  |  |  |  |  |  |
Schedule of Business Dispositions, by Dispositions [Line Items] |  |  |  |  |  |  |  |
Total sale consideration |  |  | $ 181,900 |  |  |  |  |
Proceeds from sale of business |  |  | 155,600 |  |  |  |  |
Gain on sale of business |  |  | $ 118,500 |  |  |  |  |
Velocity [Member] |  |  |  |  |  |  |  |
Schedule of Business Dispositions, by Dispositions [Line Items] |  |  |  |  |  |  |  |
Total sale consideration |  |  |  | $ 181,300 |  |  |  |
Gain on sale of business |  |  |  | $ 107,300 |  |  |  |
ISIC [Member] |  |  |  |  |  |  |  |
Schedule of Business Dispositions, by Dispositions [Line Items] |  |  |  |  |  |  |  |
Gain on sale of business |  | $ 16,900 |  |  |  |  |  |
Valor Environmental [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Percentage acquired | 98.00% |  |  |  |  |  |  |
Total purchase consideration | $ 156,400 |  |  |  |  |  |  |
Cash consideration | 156,400 |  |  |  |  |  |  |
Goodwill, Acquired During Period | 107,500 |  |  |  |  |  |  |
Goodwill, tax deductible | 0 |  |  |  |  |  |  |
Finite-lived intangible assets | $ 49,000 |  |  |  |  |  |  |

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