Revenue - Summary of Revenues by End-Use Markets and Geography (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total net sales	$ 717.6	$ 651.9
Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(28.3)	(20.0)
United States
Disaggregation of Revenue [Line Items]
Total net sales	421.1	393.3
United States | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(10.9)	(5.7)
Europe
Disaggregation of Revenue [Line Items]
Total net sales	140.3	107.4
Europe | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(5.8)	(4.3)
Asia Pacific
Disaggregation of Revenue [Line Items]
Total net sales	94.4	103.0
Asia Pacific | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(11.7)	(10.1)
Mexico
Disaggregation of Revenue [Line Items]
Total net sales	36.9	24.2
Mexico | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0
Canada
Disaggregation of Revenue [Line Items]
Total net sales	14.3	13.7
Canada | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	(0.1)
Other
Disaggregation of Revenue [Line Items]
Total net sales	10.6	10.3
Other | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.1	0.2
Aerospace and Defense
Disaggregation of Revenue [Line Items]
Total net sales	437.4	352.5
Aerospace and Defense | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(4.5)	(5.0)
Medical
Disaggregation of Revenue [Line Items]
Total net sales	86.9	80.0
Medical | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(16.0)	(11.0)
Energy
Disaggregation of Revenue [Line Items]
Total net sales	52.5	44.7
Energy | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0
Transportation
Disaggregation of Revenue [Line Items]
Total net sales	28.3	42.0
Transportation | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0
Industrial and Consumer
Disaggregation of Revenue [Line Items]
Total net sales	91.2	105.0
Industrial and Consumer | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(7.7)	(4.0)
Distribution
Disaggregation of Revenue [Line Items]
Total net sales	21.3	27.7
Distribution | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(0.1)	0.0
Specialty Alloys Operations | Operating
Disaggregation of Revenue [Line Items]
Total net sales	645.1	570.1
Specialty Alloys Operations | United States | Operating
Disaggregation of Revenue [Line Items]
Total net sales	373.7	340.7
Specialty Alloys Operations | Europe | Operating
Disaggregation of Revenue [Line Items]
Total net sales	129.8	94.9
Specialty Alloys Operations | Asia Pacific | Operating
Disaggregation of Revenue [Line Items]
Total net sales	94.4	102.7
Specialty Alloys Operations | Mexico | Operating
Disaggregation of Revenue [Line Items]
Total net sales	29.1	14.4
Specialty Alloys Operations | Canada | Operating
Disaggregation of Revenue [Line Items]
Total net sales	10.5	9.3
Specialty Alloys Operations | Other | Operating
Disaggregation of Revenue [Line Items]
Total net sales	7.6	8.1
Specialty Alloys Operations | Aerospace and Defense | Operating
Disaggregation of Revenue [Line Items]
Total net sales	417.9	332.2
Specialty Alloys Operations | Medical | Operating
Disaggregation of Revenue [Line Items]
Total net sales	61.1	55.3
Specialty Alloys Operations | Energy | Operating
Disaggregation of Revenue [Line Items]
Total net sales	51.6	43.2
Specialty Alloys Operations | Transportation | Operating
Disaggregation of Revenue [Line Items]
Total net sales	26.4	40.1
Specialty Alloys Operations | Industrial and Consumer | Operating
Disaggregation of Revenue [Line Items]
Total net sales	88.1	99.3
Specialty Alloys Operations | Distribution | Operating
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0
Performance Engineered Products | Operating
Disaggregation of Revenue [Line Items]
Total net sales	100.8	101.8
Performance Engineered Products | United States | Operating
Disaggregation of Revenue [Line Items]
Total net sales	58.3	58.3
Performance Engineered Products | Europe | Operating
Disaggregation of Revenue [Line Items]
Total net sales	16.3	16.8
Performance Engineered Products | Asia Pacific | Operating
Disaggregation of Revenue [Line Items]
Total net sales	11.7	10.4
Performance Engineered Products | Mexico | Operating
Disaggregation of Revenue [Line Items]
Total net sales	7.8	9.8
Performance Engineered Products | Canada | Operating
Disaggregation of Revenue [Line Items]
Total net sales	3.8	4.5
Performance Engineered Products | Other | Operating
Disaggregation of Revenue [Line Items]
Total net sales	2.9	2.0
Performance Engineered Products | Aerospace and Defense | Operating
Disaggregation of Revenue [Line Items]
Total net sales	24.0	25.3
Performance Engineered Products | Medical | Operating
Disaggregation of Revenue [Line Items]
Total net sales	41.8	35.7
Performance Engineered Products | Energy | Operating
Disaggregation of Revenue [Line Items]
Total net sales	0.9	1.5
Performance Engineered Products | Transportation | Operating
Disaggregation of Revenue [Line Items]
Total net sales	1.9	1.9
Performance Engineered Products | Industrial and Consumer | Operating
Disaggregation of Revenue [Line Items]
Total net sales	10.8	9.7
Performance Engineered Products | Distribution | Operating
Disaggregation of Revenue [Line Items]
Total net sales	$ 21.4	$ 27.7