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Incentive Stock Plans - Summary of Performance Share Activity (Details) - Performance-Based Stock Units - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Awards      
Beginning balance (in shares) 1,325,894    
Granted (in shares) 400,404    
Forfeited (in shares) (15,605)    
Vested (in shares) (520,167)    
Ending balance (in shares) 1,190,526 1,325,894  
Weighted Average Grant Date Fair Value      
Beginning balance (in dollars per share) $ 14.69    
Granted (in dollars per share) 14.98 $ 22.75 $ 14.60
Forfeited (in dollars per share) 16.90    
Vested (in dollars per share) 7.80    
Ending balance (in dollars per share) $ 17.77 $ 14.69