Quarterly Information - Schedule of Quarterly Information (Unaudited) (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
	Dec. 31, 2019	Mar. 30, 2019	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information [Line Items]
Impairment of assets						$ 66,916	$ 110,000
Tax benefit related to insurance recoveries			$ 18,000	$ 9,600
Deferred tax assets write-off					$ 21,800		$ 21,300
Tax benefit included in gross margin related to insurance recoveries			24,800	$ 23,300
Aggregate Assets Impaired [Member]
Quarterly Financial Information [Line Items]
Impairment of assets	$ 66,900
Raw Materials [Member]
Quarterly Financial Information [Line Items]
Gain on the sale of an equity method investment		$ 33,700
Raw Materials [Member] | Proved Producing Natural Gas Well Assets [Member]
Quarterly Financial Information [Line Items]
Impairment of assets	35,000		$ 110,000
Steel Mills [Member]
Quarterly Financial Information [Line Items]
Impairment of assets	20,000
Steel Products [Member]
Quarterly Financial Information [Line Items]
Impairment of assets	$ 11,900