Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)

v3.20.4
Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Liabilities:      
Derivative contracts $ 32,512 $ 10,956  
Goodwill impairment charge 260,000 0 $ 0
Recurring      
Assets:      
Derivative contracts 3,249 3,928  
Restoration plan assets 3,724 4,199  
Total 6,973 8,127  
Liabilities:      
Derivative contracts 34,466 11,376  
Recurring | Quoted Prices in Active Markets (Level 1)      
Assets:      
Derivative contracts 0 0  
Restoration plan assets 3,724 4,199  
Total 3,724 4,199  
Liabilities:      
Derivative contracts 0 0  
Recurring | Significant Other Observable Inputs (Level 2)      
Assets:      
Derivative contracts 3,249 3,928  
Restoration plan assets 0 0  
Total 3,249 3,928  
Liabilities:      
Derivative contracts 34,466 11,376  
Recurring | Significant Unobservable Inputs (Level 3)      
Assets:      
Derivative contracts 0 0  
Restoration plan assets 0 0  
Total 0 0  
Liabilities:      
Derivative contracts $ 0 $ 0