Revenue - Summary of Revenues by End-Use Markets and Geography (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Total net sales	$ 684.9	$ 690.1	$ 1,961.1	$ 1,792.1
Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(26.0)	(28.4)	(66.8)	(69.6)
United States
Disaggregation of Revenue [Line Items]
Total net sales	383.3	419.6	1,150.7	1,093.0
United States | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(8.1)	(10.3)	(19.9)	(27.8)
Europe
Disaggregation of Revenue [Line Items]
Total net sales	141.6	130.2	355.5	308.2
Europe | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(7.8)	(6.1)	(16.1)	(13.4)
Asia Pacific
Disaggregation of Revenue [Line Items]
Total net sales	94.7	78.8	280.7	216.2
Asia Pacific | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(10.0)	(12.0)	(30.9)	(28.3)
Mexico
Disaggregation of Revenue [Line Items]
Total net sales	29.3	25.1	88.1	90.3
Mexico | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(0.1)	0.0	0.0	0.0
Canada
Disaggregation of Revenue [Line Items]
Total net sales	21.3	18.9	49.1	45.9
Canada | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.1	0.0	0.0
Other
Disaggregation of Revenue [Line Items]
Total net sales	14.7	17.5	37.0	38.5
Other | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	(0.1)	0.1	(0.1)
Aerospace and Defense
Disaggregation of Revenue [Line Items]
Total net sales	391.1	344.2	1,064.7	885.9
Aerospace and Defense | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(6.7)	(8.6)	(18.3)	(21.2)
Medical
Disaggregation of Revenue [Line Items]
Total net sales	99.6	86.2	267.2	219.1
Medical | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(13.1)	(10.5)	(34.5)	(25.4)
Transportation
Disaggregation of Revenue [Line Items]
Total net sales	34.4	52.8	113.7	131.1
Transportation | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(0.4)	(0.2)	(0.3)	(0.7)
Energy
Disaggregation of Revenue [Line Items]
Total net sales	38.7	46.6	135.4	109.4
Energy | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	(0.1)	0.0	0.1
Industrial and Consumer
Disaggregation of Revenue [Line Items]
Total net sales	97.6	130.7	307.0	355.3
Industrial and Consumer | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	(5.8)	(9.0)	(13.6)	(22.3)
Distribution
Disaggregation of Revenue [Line Items]
Total net sales	23.5	29.6	73.1	91.3
Distribution | Intersegment
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0	(0.1)	(0.1)
Specialty Alloys Operations
Disaggregation of Revenue [Line Items]
Total net sales	608.5	603.4	1,728.0	1,546.6
Specialty Alloys Operations | United States
Disaggregation of Revenue [Line Items]
Total net sales	335.4	368.4	1,002.4	942.7
Specialty Alloys Operations | Europe
Disaggregation of Revenue [Line Items]
Total net sales	127.0	112.8	313.8	262.8
Specialty Alloys Operations | Asia Pacific
Disaggregation of Revenue [Line Items]
Total net sales	94.3	78.3	279.3	214.9
Specialty Alloys Operations | Mexico
Disaggregation of Revenue [Line Items]
Total net sales	20.9	15.9	61.6	60.0
Specialty Alloys Operations | Canada
Disaggregation of Revenue [Line Items]
Total net sales	18.5	13.9	39.4	34.6
Specialty Alloys Operations | Other
Disaggregation of Revenue [Line Items]
Total net sales	12.4	14.1	31.5	31.6
Specialty Alloys Operations | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Total net sales	367.3	321.6	1,001.5	832.1
Specialty Alloys Operations | Medical
Disaggregation of Revenue [Line Items]
Total net sales	77.7	63.9	198.6	154.2
Specialty Alloys Operations | Transportation
Disaggregation of Revenue [Line Items]
Total net sales	33.0	51.2	108.0	127.2
Specialty Alloys Operations | Energy
Disaggregation of Revenue [Line Items]
Total net sales	37.5	42.8	129.0	101.4
Specialty Alloys Operations | Industrial and Consumer
Disaggregation of Revenue [Line Items]
Total net sales	93.0	123.9	290.9	331.7
Specialty Alloys Operations | Distribution
Disaggregation of Revenue [Line Items]
Total net sales	0.0	0.0	0.0	0.0
Performance Engineered Products
Disaggregation of Revenue [Line Items]
Total net sales	102.4	115.1	299.9	315.1
Performance Engineered Products | United States
Disaggregation of Revenue [Line Items]
Total net sales	56.0	61.5	168.2	178.1
Performance Engineered Products | Europe
Disaggregation of Revenue [Line Items]
Total net sales	22.4	23.5	57.8	58.8
Performance Engineered Products | Asia Pacific
Disaggregation of Revenue [Line Items]
Total net sales	10.4	12.5	32.3	29.6
Performance Engineered Products | Mexico
Disaggregation of Revenue [Line Items]
Total net sales	8.5	9.2	26.5	30.3
Performance Engineered Products | Canada
Disaggregation of Revenue [Line Items]
Total net sales	2.8	4.9	9.7	11.3
Performance Engineered Products | Other
Disaggregation of Revenue [Line Items]
Total net sales	2.3	3.5	5.4	7.0
Performance Engineered Products | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Total net sales	30.5	31.2	81.5	75.0
Performance Engineered Products | Medical
Disaggregation of Revenue [Line Items]
Total net sales	35.0	32.8	103.1	90.3
Performance Engineered Products | Transportation
Disaggregation of Revenue [Line Items]
Total net sales	1.8	1.8	6.0	4.6
Performance Engineered Products | Energy
Disaggregation of Revenue [Line Items]
Total net sales	1.2	3.9	6.4	7.9
Performance Engineered Products | Industrial and Consumer
Disaggregation of Revenue [Line Items]
Total net sales	10.4	15.8	29.7	45.9
Performance Engineered Products | Distribution
Disaggregation of Revenue [Line Items]
Total net sales	$ 23.5	$ 29.6	$ 73.2	$ 91.4