Business Segments (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jul. 02, 2023	Jun. 30, 2024	Jul. 02, 2023
Segment Reporting Information [Line Items]
Sales	$ 1,095.3	$ 1,046.0	$ 2,138.2	$ 2,084.1
Segment EBITDA	201.3	183.8	370.7	349.1
Corporate expenses	(19.4)	(17.7)	(36.5)	(34.6)
Closed operations and other income (expense)	0.7	(1.9)	(0.6)	(3.2)
Depreciation & amortization	(37.9)	(35.9)	(73.9)	(71.0)
Interest expense, net	(28.4)	(21.3)	(55.0)	(41.2)
Income (loss) from equity investments	(0.4)	0.0	(0.8)	(0.3)
Restructuring and other charges	(5.4)	(9.2)	(8.5)	(10.4)
Loss on asset sales and sales of businesses, net	0.0		0.0
Income before income taxes	110.9	97.2	196.2	188.1
Northbrook, IL Operations
Segment Reporting Information [Line Items]
Loss on asset sales and sales of businesses, net		(0.6)		(0.6)
Houston, PA facility
Segment Reporting Information [Line Items]
Loss on asset sales and sales of businesses, net	2.3		2.3
Net proceeds on disposition of assets			3.5
Operating Segments
Segment Reporting Information [Line Items]
Sales	1,248.4	1,176.2	2,381.0	2,331.6
Depreciation & amortization	(37.9)	(35.9)	(73.9)	(71.0)
Operating Segments \| High Performance Materials & Components
Segment Reporting Information [Line Items]
Sales	643.8	562.8	1,215.7	1,092.4
Segment EBITDA	113.8	109.7	211.4	191.3
Depreciation & amortization	(17.9)	(17.9)	(34.2)	(35.3)
Operating Segments \| Advanced Alloys & Solutions
Segment Reporting Information [Line Items]
Sales	604.6	613.4	1,165.3	1,239.2
Segment EBITDA	87.5	74.1	159.3	157.8
Depreciation & amortization	(18.3)	(16.2)	(36.3)	(32.3)
Operating Segments \| Corporate Segment
Segment Reporting Information [Line Items]
Depreciation & amortization	(1.7)	(1.8)	(3.4)	(3.4)
Internal Customers \| Operating Segments
Segment Reporting Information [Line Items]
Sales	153.1	130.2	242.8	247.5
Internal Customers \| Operating Segments \| High Performance Materials & Components
Segment Reporting Information [Line Items]
Sales	81.8	35.7	123.8	94.2
Internal Customers \| Operating Segments \| Advanced Alloys & Solutions
Segment Reporting Information [Line Items]
Sales	71.3	94.5	119.0	153.3
External Customers \| Operating Segments
Segment Reporting Information [Line Items]
Sales	1,095.3	1,046.0	2,138.2	2,084.1
External Customers \| Operating Segments \| High Performance Materials & Components
Segment Reporting Information [Line Items]
Sales	562.0	527.1	1,091.9	998.2
External Customers \| Operating Segments \| Advanced Alloys & Solutions
Segment Reporting Information [Line Items]
Sales	$ 533.3	$ 518.9	$ 1,046.3	$ 1,085.9

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