Annual report pursuant to Section 13 and 15(d)

Investments in Affiliated Companies - Summarized Income Statement (Details)

v3.20.4
Investments in Affiliated Companies - Summarized Income Statement (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2020
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]                      
Gross profit $ 67,227 $ 70,172 $ 63,662 $ 72,295 $ 65,898 $ 82,913 $ 81,863 $ 67,728 $ 273,356 $ 298,402 $ 303,392
Operating income (245,623) 33,310 20,175 29,214 28,482 41,191 48,840 28,995 (162,924) 147,508 155,563
Net income $ (302,896) $ 4,436 $ 16,247 $ 509 $ 27,399 $ 18,751 $ 30,719 $ 3,441 (281,704) 80,310 59,621
Equity method investments                      
Schedule of Equity Method Investments [Line Items]                      
Sales                 278,414 380,381 351,839
Gross profit                 89,471 144,828 126,505
Operating income                 54,010 106,195 88,294
Net income                 $ 55,722 $ 107,112 $ 88,411