Revenue - Summary of Revenues by End-Use Markets and Geography (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Total net sales	$ 733.7	$ 717.6
Operating
Disaggregation of Revenue [Line Items]
Total net sales	753.2	745.9
Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(19.5)	(28.3)
United States
Disaggregation of Revenue [Line Items]
Total net sales	432.4	421.1
United States | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(6.1)	(10.9)
Europe
Disaggregation of Revenue [Line Items]
Total net sales	166.2	140.3
Europe | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(3.8)	(5.8)
Asia Pacific
Disaggregation of Revenue [Line Items]
Total net sales	83.1	94.4
Asia Pacific | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(9.6)	(11.7)
Mexico
Disaggregation of Revenue [Line Items]
Total net sales	24.8	36.9
Mexico | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.1	0.0
Canada
Disaggregation of Revenue [Line Items]
Total net sales	14.4	14.3
Canada | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0
Other
Disaggregation of Revenue [Line Items]
Total net sales	12.8	10.6
Other | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(0.1)	0.1
Aerospace and Defense
Disaggregation of Revenue [Line Items]
Total net sales	470.9	437.4
Aerospace and Defense | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(2.2)	(4.5)
Medical
Disaggregation of Revenue [Line Items]
Total net sales	74.5	86.9
Medical | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(14.6)	(16.0)
Energy
Disaggregation of Revenue [Line Items]
Total net sales	54.7	52.5
Energy | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0
Transportation
Disaggregation of Revenue [Line Items]
Total net sales	22.8	28.3
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	92.9	91.2
Industrial and Consumer | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(2.7)	(7.7)
Distribution
Disaggregation of Revenue [Line Items]
Total net sales	17.9	21.3
Distribution | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	(0.1)
Specialty Alloys Operations
Disaggregation of Revenue [Line Items]
Total net sales	656.1	641.6
Specialty Alloys Operations | Operating
Disaggregation of Revenue [Line Items]
Total net sales	659.6	645.1
Specialty Alloys Operations | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(3.5)	(3.5)
Specialty Alloys Operations | United States | Operating
Disaggregation of Revenue [Line Items]
Total net sales	380.7	373.7
Specialty Alloys Operations | Europe | Operating
Disaggregation of Revenue [Line Items]
Total net sales	154.6	129.8
Specialty Alloys Operations | Asia Pacific | Operating
Disaggregation of Revenue [Line Items]
Total net sales	82.1	94.4
Specialty Alloys Operations | Mexico | Operating
Disaggregation of Revenue [Line Items]
Total net sales	19.5	29.1
Specialty Alloys Operations | Canada | Operating
Disaggregation of Revenue [Line Items]
Total net sales	12.9	10.5
Specialty Alloys Operations | Other | Operating
Disaggregation of Revenue [Line Items]
Total net sales	9.8	7.6
Specialty Alloys Operations | Aerospace and Defense | Operating
Disaggregation of Revenue [Line Items]
Total net sales	447.0	417.9
Specialty Alloys Operations | Medical | Operating
Disaggregation of Revenue [Line Items]
Total net sales	52.9	61.1
Specialty Alloys Operations | Energy | Operating
Disaggregation of Revenue [Line Items]
Total net sales	53.9	51.6
Specialty Alloys Operations | Transportation | Operating
Disaggregation of Revenue [Line Items]
Total net sales	20.7	26.4
Specialty Alloys Operations | Industrial and Consumer | Operating
Disaggregation of Revenue [Line Items]
Total net sales	85.1	88.1
Specialty Alloys Operations | Distribution | Operating
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0
Performance Engineered Products
Disaggregation of Revenue [Line Items]
Total net sales	77.6	76.0
Performance Engineered Products | Operating
Disaggregation of Revenue [Line Items]
Total net sales	93.6	100.8
Performance Engineered Products | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(16.0)	(24.8)
Performance Engineered Products | United States | Operating
Disaggregation of Revenue [Line Items]
Total net sales	57.8	58.3
Performance Engineered Products | Europe | Operating
Disaggregation of Revenue [Line Items]
Total net sales	15.4	16.3
Performance Engineered Products | Asia Pacific | Operating
Disaggregation of Revenue [Line Items]
Total net sales	10.6	11.7
Performance Engineered Products | Mexico | Operating
Disaggregation of Revenue [Line Items]
Total net sales	5.2	7.8
Performance Engineered Products | Canada | Operating
Disaggregation of Revenue [Line Items]
Total net sales	1.5	3.8
Performance Engineered Products | Other | Operating
Disaggregation of Revenue [Line Items]
Total net sales	3.1	2.9
Performance Engineered Products | Aerospace and Defense | Operating
Disaggregation of Revenue [Line Items]
Total net sales	26.1	24.0
Performance Engineered Products | Medical | Operating
Disaggregation of Revenue [Line Items]
Total net sales	36.2	41.8
Performance Engineered Products | Energy | Operating
Disaggregation of Revenue [Line Items]
Total net sales	0.8	0.9
Performance Engineered Products | Transportation | Operating
Disaggregation of Revenue [Line Items]
Total net sales	2.1	1.9
Performance Engineered Products | Industrial and Consumer | Operating
Disaggregation of Revenue [Line Items]
Total net sales	10.5	10.8
Performance Engineered Products | Distribution | Operating
Disaggregation of Revenue [Line Items]
Total net sales	$ 17.9	$ 21.4