Earnings Per Share - Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income attributable to Ryerson Holding Corporation	$ 163.6	$ 25.3
Denominator:
Weighted average shares outstanding	38,391,000	38,117,000
Dilutive effect of stock-based awards	833,000	523,000
Weighted average shares outstanding adjusted for dilutive securities	39,224,000	38,640,000
Earnings per share
Basic	$ 4.26	$ 0.66
Diluted	$ 4.17	$ 0.66

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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