Revenue - Schedule of Net Sales Disaggregates by Major Source (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2023	Jul. 02, 2022	Jul. 01, 2023	Jul. 02, 2022
Revenue from Contract with Customers [Line Items]
Revenues	$ 9,523,256	$ 11,794,474	$ 18,233,236	$ 22,287,756
Sheet [Member]
Revenue from Contract with Customers [Line Items]
Revenues	2,645,817	3,616,333	4,748,511	6,799,396
Bar [Member]
Revenue from Contract with Customers [Line Items]
Revenues	1,599,724	1,992,463	3,197,852	3,820,194
Structural [Member]
Revenue from Contract with Customers [Line Items]
Revenues	581,952	783,121	1,220,259	1,566,392
Plate [Member]
Revenue from Contract with Customers [Line Items]
Revenues	738,279	864,150	1,378,407	1,588,694
Tubular Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	436,551	613,238	875,534	1,124,391
Rebar Fabrication [Member]
Revenue from Contract with Customers [Line Items]
Revenues	615,814	579,000	1,113,931	1,024,232
Joist [Member]
Revenue from Contract with Customers [Line Items]
Revenues	638,975	687,882	1,274,791	1,300,117
Deck [Member]
Revenue from Contract with Customers [Line Items]
Revenues	473,775	582,414	959,218	1,133,323
Other Steel Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	1,277,747	1,380,414	2,495,385	2,583,973
Raw Materials [Member]
Revenue from Contract with Customers [Line Items]
Revenues	514,622	695,459	969,348	1,347,044
Steel Mills [Member]
Revenue from Contract with Customers [Line Items]
Revenues	5,565,772	7,256,067	10,545,029	13,774,676
Steel Mills [Member] | Sheet [Member]
Revenue from Contract with Customers [Line Items]
Revenues	2,645,817	3,616,333	4,748,511	6,799,396
Steel Mills [Member] | Bar [Member]
Revenue from Contract with Customers [Line Items]
Revenues	1,599,724	1,992,463	3,197,852	3,820,194
Steel Mills [Member] | Structural [Member]
Revenue from Contract with Customers [Line Items]
Revenues	581,952	783,121	1,220,259	1,566,392
Steel Mills [Member] | Plate [Member]
Revenue from Contract with Customers [Line Items]
Revenues	738,279	864,150	1,378,407	1,588,694
Steel Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	3,442,862	3,842,948	6,718,859	7,166,036
Steel Products [Member] | Tubular Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	436,551	613,238	875,534	1,124,391
Steel Products [Member] | Rebar Fabrication [Member]
Revenue from Contract with Customers [Line Items]
Revenues	615,814	579,000	1,113,931	1,024,232
Steel Products [Member] | Joist [Member]
Revenue from Contract with Customers [Line Items]
Revenues	638,975	687,882	1,274,791	1,300,117
Steel Products [Member] | Deck [Member]
Revenue from Contract with Customers [Line Items]
Revenues	473,775	582,414	959,218	1,133,323
Steel Products [Member] | Other Steel Products [Member]
Revenue from Contract with Customers [Line Items]
Revenues	1,277,747	1,380,414	2,495,385	2,583,973
Raw Materials [Member]
Revenue from Contract with Customers [Line Items]
Revenues	514,622	695,459	969,348	1,347,044
Raw Materials [Member] | Raw Materials [Member]
Revenue from Contract with Customers [Line Items]
Revenues	$ 514,622	$ 695,459	$ 969,348	$ 1,347,044