Description of the Business and Significant Accounting Policies (Details 2) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Goodwill
Goodwill	$ 743,528,000	$ 745,158,000
Omni Source
Goodwill
Goodwill decrease due to tax benefit related to the amortization of the component	1,600,000
Metals Recycling/Ferrous Resources | Omni Source
Goodwill
Goodwill	455,097,000	456,727,000
Metals Recycling/Ferrous Resources | Butler Flat Roll Division, Structural and Rail Division, and Engineered Bar Division
Goodwill
Goodwill	95,000,000	95,000,000
Steel Operations | The Techs Operations
Goodwill
Goodwill	142,783,000	142,783,000
Steel Operations | Roanoke Bar Division
Goodwill
Goodwill	29,041,000	29,041,000
Steel Operations | Columbus Flat Roll Division
Goodwill
Goodwill	19,682,000	19,682,000
Steel Fabrication Operations | New Millennium Building Systems
Goodwill
Goodwill	$ 1,925,000	$ 1,925,000