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Investments (Tables) | 12 Months Ended
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Dec. 31, 2020
Investments Debt And Equity Securities [Abstract] |
Short-Term and Long-Term Investments Available-for-Sale | Investments classified as short-term consist of the following:
|  | Years Ended December 31, |
|  | 2020 |  |  | 2019 |
Available-for-sale investments: |  |  |  |  |  |  |  |
Time deposits and certificates of deposit |  | $ | 0.7 |  |  | $ | 13.1 |
Bankers’ acceptance drafts |  |  | 3.8 |  |  |  | 4.0 |
Commercial paper |  |  | — |  |  |  | 61.2 |
U.S. treasury obligations |  |  | 223.2 |  |  |  | 5.0 |
U.S. agency obligations |  |  | — |  |  |  | 26.1 |
|  | $ | 227.7 |  |  | $ | 109.4 |
Investments classified as long-term consist of the following:
|  | Years Ended December 31, |
|  | 2020 |  |  | 2019 |
Available-for-sale investments: |  |  |  |  |  |  |  |
Group insurance contracts |  | $ | 6.5 |  |  | $ | 5.8 |
Gross Unrealized Gains and (Losses) Aggregated by Investment Category | The following table shows the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments:
As of December 31, 2020: |  | Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized (Losses) |  |  | Estimated Fair Value |
Short-term investments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Available-for-sale investments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Time deposits and certificates of deposit |  | $ | 0.7 |  |  | $ | — |  |  | $ | — |  |  | $ | 0.7 |
Bankers' acceptance drafts |  |  | 3.8 |  |  |  | — |  |  |  | — |  |  |  | 3.8 |
U.S. treasury obligations |  |  | 223.2 |  |  |  | — |  |  |  | — |  |  |  | 223.2 |
|  | $ | 227.7 |  |  | $ | — |  |  | $ | — |  |  | $ | 227.7 |
As of December 31, 2020: |  | Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized (Losses) |  |  | Estimated Fair Value |
Long-term investments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Available-for-sale investments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Group insurance contracts |  | $ | 5.6 |  |  | $ | 0.9 |  |  | $ | — |  |  | $ | 6.5 |
As of December 31, 2019: |  | Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized (Losses) |  |  | Estimated Fair Value |
Short-term investments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Available-for-sale investments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Time deposits and certificates of deposit |  | $ | 13.1 |  |  | $ | — |  |  | $ | — |  |  | $ | 13.1 |
Bankers' acceptance drafts |  |  | 4.0 |  |  |  | — |  |  |  | — |  |  |  | 4.0 |
Commercial paper |  |  | 61.5 |  |  |  | — |  |  |  | (0.3 | ) |  |  | 61.2 |
U.S. treasury obligations |  |  | 5.0 |  |  |  | — |  |  |  | — |  |  |  | 5.0 |
U.S. agency obligations |  |  | 26.1 |  |  |  | — |  |  |  | — |  |  |  | 26.1 |
|  | $ | 109.7 |  |  | $ | — |  |  | $ | (0.3 | ) |  | $ | 109.4 |
As of December 31, 2019: |  | Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized (Losses) |  |  | Estimated Fair Value |
Long-term investments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Available-for-sale investments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Group insurance contracts |  | $ | 5.2 |  |  | $ | 0.6 |  |  | $ | — |  |  | $ | 5.8 |

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- Definition Investments classified as short-term and long-term available-for-sale investments and long-term cost method investments. + References No definition available. + Details
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- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
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