Goodwill and Other Intangible Assets - Schedule of Change in Net Carrying Amount of Goodwill by Segment (Detail) $ in Thousands	6 Months Ended
	Jul. 03, 2021 USD ($)
Goodwill [Line Items]
Balance, beginning of period	$ 2,229,672
Acquisitions	705
Other	(129)
Translation	11,310
Balance, end of period	2,241,558
Steel Mills [Member]
Goodwill [Line Items]
Balance, beginning of period	612,470
Acquisitions	705
Balance, end of period	613,175
Steel Products [Member]
Goodwill [Line Items]
Balance, beginning of period	887,625
Other	(129)
Translation	11,310
Balance, end of period	898,806
Raw Materials [Member]
Goodwill [Line Items]
Balance, beginning of period	729,577
Balance, end of period	$ 729,577