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Share-Based Compensation - Summary of Performance-Based Stock Units (Details) - Performance-Based Stock Units - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Shares [Roll Forward]      
Nonvested, beginning of period (in shares) 407,000    
Granted (in shares) 4,000   0
Shares adjustment for performance (in shares) [1] (74,000)    
Vested (in shares) (86,000)    
Forfeited (in shares) (165,000)    
Nonvested, end of period (in shares) 86,000 407,000  
Weighted-Average Grant Date Fair Value [Roll Forward]      
Nonvested, beginning of period (in dollars per share) $ 20.29    
Granted (in dollars per share) 21.49 $ 20.20  
Shares adjustment for performance (in dollars per share) [1] 20.26    
Vested (in dollars per share) 20.42    
Forfeited (in dollars per share) 20.26    
Nonvested, end of period (in dollars per share) $ 20.30 $ 20.29  
[1] Represents the number of shares at target for certain performance-based stock units that are no longer eligible to be earned as a result of actual performance being below the applicable performance targets. These awards are included in the nonvested balance at January 1, 2020 and the number of shares granted above.