|**Stock-Based Compensation (Tables)**                                                           | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                             
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|**Share-based Payment Arrangement [Abstract]**                                                  |                                                                                                                                                                                                                                                                                                                                                                                                             
|Restricted shares, performance-based restricted share units and performance share unit activity | The following table presents activity for non-vested RSUs and performance share units under the Plan in2019.Number of AwardsWeighted Average Grant Date Fair ValueBalance as of January 1, 20192,204,148$43.98Awards granted1,051,05343.86Awards vested(801,504)36.81Awards forfeited, canceled or expired(379,425)45.98Performance-based adjustment40,91444.86Balance as of December 31, 20192,115,18646.25
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|                                                                                                | Number of Awards                                                                                                                                                                                                                                                                                                                                                                                            
|Balance as of January 1, 2019                                                                   | 2,204,148                                                                                                                                                                                                                                                                                                                                                                                                   
|Awards granted                                                                                  | 1,051,053                                                                                                                                                                                                                                                                                                                                                                                                   
|Awards vested                                                                                   | (801,504                                                                                                                                                                                                                                                                                                                                                                                                    
|Awards forfeited, canceled or expired                                                           | (379,425                                                                                                                                                                                                                                                                                                                                                                                                    
|Performance-based adjustment                                                                    | 40,914                                                                                                                                                                                                                                                                                                                                                                                                      
|Balance as of December 31, 2019                                                                 | 2,115,186                                                                                                                                                                                                                                                                                                                                                                                                   

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