Segment Information - Results Footnote (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Operating income (loss)
Corporate SG & A	$ (107,242)	$ (102,614)	$ (324,530)	$ (310,076)
Profit sharing	(17,848)	(45,304)	(64,396)	(114,301)
Operating income (loss)	228,045	531,572	804,919	1,356,856
Gross profit	359,839	686,081	1,214,575	1,801,579
Assets
Accounts receivable	986,946		986,946		$ 1,043,756
Cash and equivalents	1,146,007		1,146,007		828,220
Short-term Investments	69,529		69,529		228,783
Inventories	1,767,020		1,767,020		1,859,168
Property, plant and equipment, net	3,031,731		3,031,731		2,945,767
Other assets	100,685		100,685		25,166
Total assets	7,943,247		7,943,247		$ 7,703,563
Operating Segment | Other
Operating income (loss)
Corporate SG & A	(15,400)	(13,800)	(56,000)	(44,000)
Company-wide equity-based compensation	(8,700)	(7,800)	(26,100)	(24,800)
Profit sharing	(17,000)	(43,400)	(61,300)	(109,600)
Other, net	(1,300)	(2,100)	(5,100)	(7,700)
Operating income (loss)	(42,441)	(67,113)	(148,514)	(186,137)
Assets
Cash and equivalents	1,072,500		1,072,500
Short-term Investments	69,500		69,500
Accounts receivable	7,800		7,800
Inventories	36,500		36,500
Property, plant and equipment, net	271,800		271,800
Intra-company debt	8,700		8,700
Other assets	47,000		47,000
Total assets	1,513,798		1,513,798
Operating Segment | Metals Recycling Operations
Operating income (loss)
Operating income (loss)	(101)	14,674	24,480	62,027
Assets
Total assets	972,493		972,493
Eliminations
Operating income (loss)
Operating income (loss)	624	(2,941)	7,214	(7,977)
Gross profit	400	$ (2,900)	6,600	$ (8,000)
Assets
Accounts receivable	(61,200)		(61,200)
Intra-company debt	(8,700)		(8,700)
Other assets	(7,400)		(7,400)
Total assets	$ (77,298)		$ (77,298)