Business Segments - Schedule of Results of Operation, Depreciation and Amortization, Capital Expenditures and Total Assets by Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Jun. 30, 2024
Net Sales
Total net sales	$ 676.9	$ 624.2	$ 1,394.5	$ 1,276.1
Operating Income (Loss)
Consolidated operating income	118.9	69.8	232.5	138.8
Depreciation and Amortization
Consolidated depreciation and amortization	34.3	33.6	68.1	66.7
Capital Expenditures
Consolidated capital expenditures	29.3	25.3	56.2	47.3
Total Assets
Consolidated total assets	3,326.7		3,326.7		$ 3,291.7
Operating | Specialty Alloys Operations
Net Sales
Total net sales	601.5	549.4	1,246.6	1,119.4
Operating Income (Loss)
Consolidated operating income	135.6	83.3	270.2	164.1
Depreciation and Amortization
Consolidated depreciation and amortization	28.8	28.4	57.4	56.2
Capital Expenditures
Consolidated capital expenditures	25.2	20.3	45.7	39.0
Total Assets
Consolidated total assets	2,597.5		2,597.5		2,542.2
Operating | Performance Engineered Products
Net Sales
Total net sales	95.0	95.7	195.8	197.4
Operating Income (Loss)
Consolidated operating income	7.0	7.1	14.3	16.2
Depreciation and Amortization
Consolidated depreciation and amortization	4.1	4.0	8.0	8.0
Capital Expenditures
Consolidated capital expenditures	3.6	2.9	9.7	6.2
Total Assets
Consolidated total assets	439.1		439.1		431.5
Corporate
Operating Income (Loss)
Consolidated operating income	(23.6)	(20.7)	(51.6)	(42.0)
Depreciation and Amortization
Consolidated depreciation and amortization	1.4	1.2	2.7	2.5
Capital Expenditures
Consolidated capital expenditures	0.5	2.1	0.8	2.1
Total Assets
Consolidated total assets	294.4		294.4		334.8
Intersegment
Net Sales
Total net sales	(19.6)	(20.9)	(47.9)	(40.7)
Operating Income (Loss)
Consolidated operating income	(0.1)	$ 0.1	(0.4)	$ 0.5
Total Assets
Consolidated total assets	$ (4.3)		$ (4.3)		$ (16.8)