Segment Information - Results Footnote (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Operating income (loss)
Corporate SG & A	$ (112,898)	$ (111,038)
Profit sharing	(21,454)	(23,677)
Operating income (loss)	273,686	291,842
Gross profit	415,229	433,570
Assets
Cash and equivalents	1,235,478		$ 1,381,460
Short-term Investments	219,193		262,174
Accounts receivable	998,400
Inventories	1,644,538		1,689,043
Property, plant and equipment, net	3,327,605		3,135,886
Other assets	101,571		106,038
Total assets	8,344,923		$ 8,275,765
Operating Segment | Other
Operating income (loss)
Corporate SG & A	(17,200)	(22,600)
Company-wide equity-based compensation	(8,200)	(9,000)
Profit sharing	(21,300)	(23,000)
Other, net	300	(2,300)
Operating income (loss)	(46,355)	(56,920)
Assets
Cash and equivalents	1,169,600
Short-term Investments	219,200
Accounts receivable	8,600
Inventories	21,100
Property, plant and equipment, net	148,800
Intra-company debt	8,100
Other assets	44,500
Total assets	1,619,924
Operating Segment | Metals Recycling Operations
Operating income (loss)
Operating income (loss)	5,528	16,962
Assets
Total assets	918,403
Eliminations
Operating income (loss)
Operating income (loss)	(3,044)	2,099
Gross profit	(3,300)	$ (2,100)
Assets
Accounts receivable	(38,600)
Intra-company debt	(8,100)
Other assets	(11,100)
Total assets	$ (57,817)