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Fair Value Measurements - Quantitative Information used in Valuing Level 3 Liabilities (Details) - Significant Unobservable Inputs (Level 3) - Affiliate equity purchase obligations - Discounted cash flow $ in Millions | Jun. 30, 2021 USD ($) | Dec. 31, 2020 USD ($)
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Quantitative information for Level 3 Fair Value Measurements Liabilities |  |
Fair Value | $ 47.9 | $ 22.0
Growth rates | Minimum |  |
Quantitative information for Level 3 Fair Value Measurements Liabilities |  |
Affiliate equity purchase obligations, measurement input | 0.01 | (0.05)
Growth rates | Maximum |  |
Quantitative information for Level 3 Fair Value Measurements Liabilities |  |
Affiliate equity purchase obligations, measurement input | 0.06 | 0.08
Growth rates | Weighted Average |  |
Quantitative information for Level 3 Fair Value Measurements Liabilities |  |
Affiliate equity purchase obligations, measurement input | 0.04 | 0.03
Discount rates | Minimum |  |
Quantitative information for Level 3 Fair Value Measurements Liabilities |  |
Affiliate equity purchase obligations, measurement input | 0.15 | 0.14
Discount rates | Maximum |  |
Quantitative information for Level 3 Fair Value Measurements Liabilities |  |
Affiliate equity purchase obligations, measurement input | 0.16 | 0.16
Discount rates | Weighted Average |  |
Quantitative information for Level 3 Fair Value Measurements Liabilities |  |
Affiliate equity purchase obligations, measurement input | 0.15 | 0.15

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