Segment Information, Geographic and Product Data - Schedule of Results of Operation, Depreciation and Amortization, Capital Expenditures and Total Assets by Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Consolidated net sales	$ 1,836.3	$ 1,475.6	$ 2,181.1
Consolidated operating (loss) income	(24.9)	(248.6)	25.3
Consolidated depreciation and amortization	131.4	123.6	123.9
Consolidated capital expenditures	91.3	100.5	171.4
Consolidated total assets	2,932.3	2,971.2
Corporate costs (including restructuring and asset impairment charges)
Segment Reporting Information [Line Items]
Consolidated operating (loss) income	(52.8)	(144.3)	(205.0)
Consolidated depreciation and amortization	5.5	5.6	6.2
Consolidated capital expenditures	2.9	25.2	54.9
Consolidated total assets	248.9	402.2
Intersegment
Segment Reporting Information [Line Items]
Consolidated net sales	(73.8)	(46.4)	(51.6)
Consolidated operating (loss) income	0.2	(0.4)	1.7
Consolidated depreciation and amortization	0.0	0.0	(0.6)
Consolidated capital expenditures	0.1	(0.1)	0.0
Consolidated total assets	2.1	0.4
Specialty Alloys Operations | Operating
Segment Reporting Information [Line Items]
Consolidated net sales	1,565.6	1,262.2	1,831.6
Consolidated operating (loss) income	9.6	(87.4)	239.0
Consolidated depreciation and amortization	110.1	99.7	93.5
Consolidated capital expenditures	77.5	69.4	99.3
Consolidated total assets	2,262.4	2,150.1
Performance Engineered Products | Operating
Segment Reporting Information [Line Items]
Consolidated net sales	344.5	259.8	401.1
Consolidated operating (loss) income	18.1	(16.5)	(10.4)
Consolidated depreciation and amortization	15.8	18.3	24.8
Consolidated capital expenditures	10.8	6.0	$ 17.2
Consolidated total assets	$ 418.9	$ 418.5