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, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2023
Net Sales
Total net sales	$ 624.2	$ 579.1	$ 1,276.1	$ 1,102.0
Operating Income (Loss)
Consolidated operating income	69.8	22.6	138.8	30.9
Depreciation and Amortization
Consolidated depreciation and amortization	33.6	32.5	66.7	64.8
Capital Expenditures
Consolidated capital expenditures	25.3	17.5	47.3	31.0
Total Assets
Consolidated total assets	3,159.2		3,159.2		$ 3,053.9
Operating | Specialty Alloys Operations
Net Sales
Total net sales	549.4	495.8	1,119.4	943.2
Operating Income (Loss)
Consolidated operating income	83.3	30.3	164.1	50.2
Depreciation and Amortization
Consolidated depreciation and amortization	28.4	27.3	56.2	54.4
Capital Expenditures
Consolidated capital expenditures	20.3	16.0	39.0	27.4
Total Assets
Consolidated total assets	2,551.3		2,551.3		2,461.2
Operating | Performance Engineered Products
Net Sales
Total net sales	95.7	106.7	197.4	200.0
Operating Income (Loss)
Consolidated operating income	7.1	9.3	16.2	15.6
Depreciation and Amortization
Consolidated depreciation and amortization	4.0	3.8	8.0	7.7
Capital Expenditures
Consolidated capital expenditures	2.9	1.2	6.2	3.1
Total Assets
Consolidated total assets	470.6		470.6		451.6
Corporate
Operating Income (Loss)
Consolidated operating income	(20.7)	(16.4)	(42.0)	(33.5)
Depreciation and Amortization
Consolidated depreciation and amortization	1.2	1.4	2.5	2.7
Capital Expenditures
Consolidated capital expenditures	2.0	0.3	2.2	0.5
Total Assets
Consolidated total assets	152.8		152.8		159.0
Intersegment
Net Sales
Total net sales	(20.9)	(23.4)	(40.7)	(41.2)
Operating Income (Loss)
Consolidated operating income	0.1	(0.6)	0.5	(1.4)
Capital Expenditures
Consolidated capital expenditures	0.1	$ 0.0	(0.1)	$ 0.0
Total Assets
Consolidated total assets	$ (15.5)		$ (15.5)		$ (17.9)