Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net sales	$ 1,748.8	$ 1,147.3
Cost of materials sold	1,338.7	949.4
Gross profit	410.1	197.9
Warehousing, delivery, selling, general, and administrative	175.3	171.8
Gain on sale of assets		(20.3)
Operating profit	234.8	46.4
Other income and (expense), net	(5.7)	0.3
Interest and other expense on debt	(10.3)	(13.5)
Income before income taxes	218.8	33.2
Provision for income taxes	55.0	7.6
Net income	163.8	25.6
Less: Net income attributable to noncontrolling interest	0.2	0.3
Net income attributable to Ryerson Holding Corporation	163.6	25.3
Comprehensive income	166.7	28.0
Less: Comprehensive income attributable to noncontrolling interest	0.2	0.2
Comprehensive income attributable to Ryerson Holding Corporation	$ 166.5	$ 27.8
Basic earnings per share	$ 4.26	$ 0.66
Diluted earnings per share	4.17	$ 0.66
Dividends declared per share	$ 0.10