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Fair Value Measurements - Fair Value Measurements (Details) - Recurring Basis [Member] - USD ($) $ in Thousands | Sep. 30, 2025 | Dec. 31, 2024
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Fair Value Measurements [Abstract] |  |  |  |  |
Cash equivalents | [1] | $ 167,298 |  | $ 180,445 |
Total |  | 2,154,279 |  | 2,241,716 |
Corporate Debt Securities [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities |  | 1,058,068 | [2] | 1,032,066 | [3]
Debt Securities Issued by U.S. Government Agencies [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 150,590 |  | 208,998 |
Debt Securities Issued by the U.S. Treasury [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities |  | 768,085 | [4] | 806,724 | [3]
Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 6,284 |  | 7,524 |
Other Municipal Debt Securities [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 698 |  | 696 |
Publicly Traded Equity Securities [Member] | Other Current Assets [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Equity securities | [5] | 3,256 |  | 5,263 |
Quoted Prices in Active Markets (Level 1) [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Cash equivalents | [1] | 167,298 |  | 180,445 |
Total |  | 938,639 |  | 992,432 |
Quoted Prices in Active Markets (Level 1) [Member] | Corporate Debt Securities [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities |  | 0 | [2] | 0 | [3]
Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by U.S. Government Agencies [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 0 |  | 0 |
Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by the U.S. Treasury [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities |  | 768,085 | [4] | 806,724 | [3]
Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 0 |  | 0 |
Quoted Prices in Active Markets (Level 1) [Member] | Other Municipal Debt Securities [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 0 |  | 0 |
Quoted Prices in Active Markets (Level 1) [Member] | Publicly Traded Equity Securities [Member] | Other Current Assets [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Equity securities | [5] | 3,256 |  | 5,263 |
Significant Other Observable Inputs (Level 2) [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Cash equivalents | [1] | 0 |  | 0 |
Total |  | 1,215,640 |  | 1,249,284 |
Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities |  | 1,058,068 | [2] | 1,032,066 | [3]
Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by U.S. Government Agencies [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 150,590 |  | 208,998 |
Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by the U.S. Treasury [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities |  | 0 | [4] | 0 | [3]
Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 6,284 |  | 7,524 |
Significant Other Observable Inputs (Level 2) [Member] | Other Municipal Debt Securities [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Available-for-sale securities | [3] | 698 |  | 696 |
Significant Other Observable Inputs (Level 2) [Member] | Publicly Traded Equity Securities [Member] | Other Current Assets [Member] |  |  |  |  |
Fair Value Measurements [Abstract] |  |  |  |  |
Equity securities | [5] | $ 0 |  | $ 0 |
[1] | Included in cash and cash equivalents.
[2] | $39.9 million was included in cash and cash equivalents, with the difference included in short-term investments.
[3] | Included in short-term investments.
[4] | $36.0 million was included in cash and cash equivalents, with the difference included in short-term investments.
[5] | Included in other current assets.

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