Description of the Business and Summary of Significant Accounting Policies (Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill
Goodwill	$ 477,471	$ 502,067
Goodwill impairment loss	0	0	$ 0
Compensation expense for stock-based employee compensation plan	60,100	69,200	$ 80,200
Steel Operations
Goodwill
Goodwill	272,133	272,133
Metals Recycling Operations
Goodwill
Goodwill	203,413	228,009
Metals Recycling Operations | OmniSource
Goodwill
Goodwill impaired accumulated impairment loss	346,800	346,800
Steel Fabrication Operations
Goodwill
Goodwill	$ 1,925	$ 1,925