Revenue - Schedule of Net Sales Disaggregates by Major Source (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2022	Jul. 03, 2021	Jul. 02, 2022	Jul. 03, 2021
Revenue from Contract with Customers [Line Items]
Revenues	$ 11,794,474	$ 8,789,164	$ 22,287,756	$ 15,806,304
Sheet [Member]
Revenue from Contract with Customers [Line Items]
Revenues	3,616,333	3,104,304	6,799,396	5,455,759
Bar [Member]
Revenue from Contract with Customers [Line Items]
Revenues	1,992,463	1,515,115	3,820,194	2,776,157
Structural [Member]
Revenue from Contract with Customers [Line Items]
Revenues	783,121	619,541	1,566,392	1,096,736
Plate [Member]
Revenue from Contract with Customers [Line Items]
Revenues	864,150	670,949	1,588,694	1,190,034
Tubular Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	613,238	512,503	1,124,391	887,156
Rebar Fabrication [Member]
Revenue from Contract with Customers [Line Items]
Revenues	579,000	480,727	1,024,232	867,284
Joist [Member]
Revenue from Contract with Customers [Line Items]
Revenues	687,882	257,202	1,300,117	486,331
Deck [Member]
Revenue from Contract with Customers [Line Items]
Revenues	582,414	227,748	1,133,323	421,161
Other Steel Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	1,380,414	762,927	2,583,973	1,389,230
Raw Materials [Member]
Revenue from Contract with Customers [Line Items]
Revenues	695,459	638,148	1,347,044	1,236,456
Steel Mills [Member]
Revenue from Contract with Customers [Line Items]
Revenues	7,256,067	5,909,909	13,774,676	10,518,686
Steel Mills [Member] | Sheet [Member]
Revenue from Contract with Customers [Line Items]
Revenues	3,616,333	3,104,304	6,799,396	5,455,759
Steel Mills [Member] | Bar [Member]
Revenue from Contract with Customers [Line Items]
Revenues	1,992,463	1,515,115	3,820,194	2,776,157
Steel Mills [Member] | Structural [Member]
Revenue from Contract with Customers [Line Items]
Revenues	783,121	619,541	1,566,392	1,096,736
Steel Mills [Member] | Plate [Member]
Revenue from Contract with Customers [Line Items]
Revenues	864,150	670,949	1,588,694	1,190,034
Steel Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	3,842,948	2,241,107	7,166,036	4,051,162
Steel Products [Member] | Tubular Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	613,238	512,503	1,124,391	887,156
Steel Products [Member] | Rebar Fabrication [Member]
Revenue from Contract with Customers [Line Items]
Revenues	579,000	480,727	1,024,232	867,284
Steel Products [Member] | Joist [Member]
Revenue from Contract with Customers [Line Items]
Revenues	687,882	257,202	1,300,117	486,331
Steel Products [Member] | Deck [Member]
Revenue from Contract with Customers [Line Items]
Revenues	582,414	227,748	1,133,323	421,161
Steel Products [Member] | Other Steel Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	1,380,414	762,927	2,583,973	1,389,230
Raw Materials [Member]
Revenue from Contract with Customers [Line Items]
Revenues	695,459	638,148	1,347,044	1,236,456
Raw Materials [Member] | Raw Materials [Member]
Revenue from Contract with Customers [Line Items]
Revenues	$ 695,459	$ 638,148	$ 1,347,044	$ 1,236,456