Quarterly report pursuant to Section 13 or 15(d)

Share-based Compensation (Narrative) (Details)

v3.21.1
Share-based Compensation (Narrative) (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
RSUs      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted (in shares) 570,000 232,000  
TSR, maximum percent of performance period 5.00%    
Vested (in shares) (21,000) (16,000)  
Grant date fair value $ 0.3 $ 0.7  
Unrecognized compensation costs $ 32.7    
Period for recognition (in years) 2 years 6 months    
Performance-based Equity Awards      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vested (in shares) 0    
Grant date fair value   $ 2.9  
Performance-based Equity Awards | Vesting Percentage, Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting rights     0.00%
Performance-based Equity Awards | Vesting Percentage, Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting rights     300.00%
Cash-Settled RSUs      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted (in shares) 0 86,000  
Vested (in shares) (1,000) (1,000)  
Unrecognized compensation costs $ 5.4    
Award vesting period (in years) 3 years    
Period for recognition (in years) 1 year 8 months 12 days    
Cash Stock Appreciation Rights (SARs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Unrecognized compensation costs $ 6.5   $ 1.7