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Share-Based Compensation - Stock Options Narrative (Details) - USD ($)
$ / shares in Units, shares in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award      
Fair value of stock options granted $ 4,400,000 $ 34,200,000 $ 1,000,000.0
Total intrinsic value of options exercised 0.0 200,000 8,200,000
Cash received for options exercised 0 $ 900,000 $ 9,700,000
Intrinsic value of exercisable options outstanding $ 500,000    
Weighted average fair value of options granted (in dollars per share) $ 18.33 $ 18.36 $ 48.64
Stock Options      
Share-based Compensation Arrangement by Share-based Payment Award      
Options available for future grant under the Company's option plans (in shares) 1.2    
Stock Options | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award      
Vesting period of options 3 years    
Expiration period of options 7 years    
Stock Options | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award      
Vesting period of options 5 years