Intangible Assets, net (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Intangible assets subject to amortization:
Intangible assets subject to amortization, Gross Carrying Amount	$ 639.5		$ 720.0
Intangible assets subject to amortization, Accumulated Amortization	(388.3)		(447.5)
Intangible assets
Intangible assets, Gross Carrying Amount	1,362.6		1,478.6
Amortization expense for intangible assets	20.9	$ 21.5
Changes in intangible assets due to foreign currency translation gains (losses)	(3.2)	$ 1.7
Summary of estimated aggregate amortization expense for each of the succeeding five years
2020 (remaining six months)	18.9
2021	37.3
2022	36.6
2023	32.4
2024	28.8
2025	24.6
Fry Steel
Intangible assets
Intangible assets, Gross Carrying Amount	56.3
Trade names
Intangible assets not subject to amortization:
Intangible assets not subject to amortization, Gross Carrying Amount	723.1		758.6
Intangible assets
Impairment losses of intangible assets, indefinite-lived	64.3
Trade names | Fry Steel
Intangible assets not subject to amortization:
Intangible assets not subject to amortization, Gross Carrying Amount	$ 30.3
Covenants not to compete
Intangible assets subject to amortization:
Weighted average amortizable life in years	5 years
Intangible assets subject to amortization, Gross Carrying Amount	$ 0.7		0.7
Intangible assets subject to amortization, Accumulated Amortization	$ (0.4)		(0.4)
Customer lists/relationships
Intangible assets subject to amortization:
Weighted average amortizable life in years	14 years 8 months 12 days
Intangible assets subject to amortization, Gross Carrying Amount	$ 629.8		710.1
Intangible assets subject to amortization, Accumulated Amortization	(378.9)		(438.1)
Intangible assets
Impairment losses of intangible assets, finite-lived	24.7
Customer lists/relationships | Fry Steel
Intangible assets subject to amortization:
Intangible assets subject to amortization, Gross Carrying Amount	$ 26.0
Software
Intangible assets subject to amortization:
Weighted average amortizable life in years	10 years
Intangible assets subject to amortization, Gross Carrying Amount	$ 8.1		8.1
Intangible assets subject to amortization, Accumulated Amortization	$ (8.1)		(8.1)
Other
Intangible assets subject to amortization:
Weighted average amortizable life in years	7 years 3 months 18 days
Intangible assets subject to amortization, Gross Carrying Amount	$ 0.9		1.1
Intangible assets subject to amortization, Accumulated Amortization	$ (0.9)		$ (0.9)