Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Revenue from External Customers by Product Line

Net sales by product line are presented below:

	2017		2016		2015
Carbon steel	$	4,034.5	$	4,014.5	$	4,746.8
Stainless and electrical steel	1,687.6		1,654.1		1,733.0
Tubular, components and other	358.4		213.9		213.1
Total	$	6,080.5	$	5,882.5	$	6,692.9

Schedule of Percentage of Net Sales by Market

Percentages of our net sales to various markets are presented below:

	2017		2016		2015
Automotive	65	%	66	%	60	%
Infrastructure and Manufacturing	16	%	16	%	16	%
Distributors and Converters	19	%	18	%	24	%