Annual report pursuant to Section 13 and 15(d)

Benefit Plans and Collective Bargaining Agreements - United Steelworkers Narrative (Details)

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Benefit Plans and Collective Bargaining Agreements - United Steelworkers Narrative (Details) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Defined Contribution Plan Disclosure [Line Items]    
Total employer contributions to plans under collective-bargaining arrangements $ 29,851 $ 28,469
401(k) and Profit Sharing Plan    
Defined Contribution Plan Disclosure [Line Items]    
Employee maximum contribution percentage 60.00%  
Employee maximum contribution amount $ 19,500  
Minimum age to qualify under Economic Growth and Tax Relief Reconciliation Act 50 years  
Employee additional contribution eligible under economic growth and tax relief reconciliation act $ 6,500  
Employee maximum contribution eligible under economic growth and tax relief reconciliation act $ 26,000  
Employer contribution as a percentage of participant's eligible compensation 3.00%  
Matching percentage by employer of employees' gross pay 4.00%  
Employer contributions to defined benefit plans $ 200,000 200,000
Employer discretionary contribution 0 0
Maximum | Other Pension, Postretirement and Supplemental Plans    
Defined Contribution Plan Disclosure [Line Items]    
Employer contributions to defined benefit plans $ 200,000 $ 200,000
Funding percentage under defined benefit plans   84.00%
Employer contribution percentage of each participant's eligible compensation 4.25%  
Employer's contribution percentage of total contributions 5.00%