Goodwill and Other Intangible Assets - Schedule of Change in Net Carrying Amount of Goodwill by Segment (Detail) $ in Thousands	9 Months Ended
	Oct. 03, 2015 USD ($)
Goodwill [Line Items]
Balance, beginning of period	$ 2,068,664
Translation	(41,108)
Other	(3,768)
Balance, end of period	2,023,788
Steel Mills [Member]
Goodwill [Line Items]
Balance, beginning of period	594,402
Other	(3,768)
Balance, end of period	590,634
Steel Products [Member]
Goodwill [Line Items]
Balance, beginning of period	744,685
Translation	(41,108)
Balance, end of period	703,577
Raw Materials [Member]
Goodwill [Line Items]
Balance, beginning of period	729,577
Balance, end of period	$ 729,577