Inventories - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Inventory, Net [Abstract]
Inventory valuation reserves	$ 318,862							$ 318,862	$ 240,363
Lower of cost or market inventory valuation adjustment	$ 149,200	$ 62,800	$ 269,900		$ 232,300			78,499	$ (119,775)	$ 136,305
Increase (decrease) in costs of products sold				$ 36,600		$ 25,300	$ 33,800	$ 36,900			$ 37,900