Discontinued Operations - Schedule of Loss from Discontinued Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations, net of tax	$ (26.2)	$ (24.3)	$ (25.9)
Disposed of by Sale | Aluminum Products Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales	180.6	210.4	161.0
Cost of sales	164.9	220.0	169.3
Selling, general and administrative	15.8	14.2	11.5
Restructuring and other special charges	0.0	3.9	4.0
Goodwill impairment	0.0	0.0	4.6
Operating loss	(0.1)	(27.7)	(28.4)
Interest expense	(3.3)	(2.8)	(3.0)
Loss from operation of discontinued operations	(3.4)	(30.5)	(31.4)
Loss on sale of discontinued operations	(28.3)	(1.8)
Income tax benefit	5.5	8.0	5.5
Loss from discontinued operations, net of tax	(26.2)	(24.3)	(25.9)
Interest expense allocated	$ 3.0	$ 2.5	$ 2.6