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	9 Months Ended
	Oct. 04, 2014	Oct. 04, 2014
Goodwill [Line Items]
Balance, beginning of period		$ 1,973,608
Other	26,400	26,663
Translation		(17,495)
Balance, end of period	1,982,776	1,982,776
Steel Mills [Member]
Goodwill [Line Items]
Balance, beginning of period		495,897
Other		0
Translation		0
Balance, end of period	495,897	495,897
Steel Products [Member]
Goodwill [Line Items]
Balance, beginning of period		774,486
Other		311
Translation		(17,495)
Balance, end of period	757,302	757,302
Raw Materials [Member]
Goodwill [Line Items]
Balance, beginning of period		703,225
Other		26,352
Translation		0
Balance, end of period	$ 729,577	$ 729,577