Goodwill and Other Intangible Assets - Schedule of Change in Net Carrying Amount of Goodwill by Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 04, 2015
Goodwill [Line Items]
Balance, beginning of period	$ 2,068,664
Translation	(25,349)
Balance, end of period	2,043,315
Steel Mills [Member]
Goodwill [Line Items]
Balance, beginning of period	594,402
Translation	0
Balance, end of period	594,402
Steel Products [Member]
Goodwill [Line Items]
Balance, beginning of period	744,685
Translation	(25,349)
Balance, end of period	719,336
Raw Materials [Member]
Goodwill [Line Items]
Balance, beginning of period	729,577
Translation	0
Balance, end of period	$ 729,577