Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Additional Information (Details)

v3.20.4
Employee Benefit Plans - Additional Information (Details)
12 Months Ended
Dec. 31, 2020
USD ($)
Plans
Members
Employer
shares
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Jun. 30, 2020
shares
Jun. 30, 2019
shares
Jun. 30, 2017
shares
Jun. 30, 2014
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of active stock compensation plans | Plans 2            
Restricted stock shares | shares 69,000            
Number of employers obligated to make contribution under multiemployer plan | Employer 153            
Number of employee increase / (decrease) under multiemployer benefit percentage (18.60%) 5.50%          
Total contributions of multi employer Plan   5.00%          
SERP              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Members of senior management | Members 13            
Options | Selling, general and administrative expenses              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Compensation expense | $ $ 2,300,000 $ 2,300,000 $ 2,300,000        
Restricted stock units and restricted stock awards              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Tax benefit recognized | $ 2,500,000 2,900,000 3,000,000.0        
Restricted stock units and restricted stock awards | Selling, general and administrative expenses              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Compensation expense | $ 11,700,000 10,800,000 11,900,000        
Restricted stock units and restricted stock awards              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Compensation expense not yet recognized | $ $ 28,300,000            
Total compensation cost related to non-vested options expected to be recognized over weighted average period 5 years 6 months            
401(k) plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Employer contribution | $ $ 8,400,000 $ 8,900,000 $ 9,200,000        
2012 Formula Plan | Restricted stock awards | Board of Directors              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Restricted stock shares | shares 69,000            
2012 Formula Plan | Class A common stock              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares authorized | shares         500,000   300,000
2012 Plan | Restricted stock units              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock award vesting period 3 years            
2012 Plan | Restricted stock units | Executive officers and other key associates              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Restricted stock shares | shares 2,273,000            
2012 Plan | Class A common stock              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares authorized | shares       6,000,000   4,000,000 2,000,000
2012 Formula Plan and 2004 Plan | Class A common stock | Options              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock option expiration period 10 years            
2012 Formula Plan and 2004 Plan | Class A common stock | Options | Minimum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock award vesting period 6 months            
2012 Formula Plan and 2004 Plan | Class A common stock | Options | Maximum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock award vesting period 3 years            
2012 Formula Plan and 2004 Plan | Class A common stock | Restricted stock awards and restricted stock units | Minimum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock award vesting period 1 year            
2012 Formula Plan and 2004 Plan | Class A common stock | Restricted stock awards and restricted stock units | Maximum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock award vesting period 3 years