XML 66 R48.htm IDEA: XBRL DOCUMENT v3.20.4
Revenue From Contracts With Customers - Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Disaggregation of Revenue [Line Items]      
Total Revenues $ 1,224,361 $ 1,790,793 $ 1,895,910
Graphite Electrodes - Long-term agreements      
Disaggregation of Revenue [Line Items]      
Total Revenues 1,069,772 1,437,354 1,341,557
Graphite Electrodes - Short-term agreements and spot sales      
Disaggregation of Revenue [Line Items]      
Total Revenues 123,845 260,979 395,928
By-products and other      
Disaggregation of Revenue [Line Items]      
Total Revenues $ 30,744 $ 92,460 $ 158,425