Goodwill and Other Intangible Assets, Net - Narrative (Details)	12 Months Ended
	Jun. 30, 2021 USD ($) reporting_unit	Jun. 30, 2020 USD ($) facility	Jun. 30, 2019 USD ($)
Goodwill [Line Items]
Number of reporting units | reporting_unit	3
Goodwill	$ 241,400,000	$ 290,400,000	$ 326,400,000
Goodwill impairment	52,800,000	34,600,000	0
Amortization expense	6,900,000	8,300,000	7,300,000
Accumulated goodwill impairment loss	(134,600,000)	(81,800,000)	(47,200,000)
Estimated annual amortization expense for 2022	6,800,000
Estimated annual amortization expense for 2023	6,800,000
Estimated annual amortization expense for 2024	6,600,000
Estimated annual amortization expense for 2025	6,500,000
Estimated annual amortization expense for 2026	6,500,000
Impairment of intangible assets		7,300,000
Finite-lived intangible assets	$ 43,100,000	52,100,000
Special Alloy Operations Reporting Unit
Goodwill [Line Items]
Percentage of goodwill	81.00%
Reporting unit, percentage of fair value in excess of carrying amount	26.30%
Reporting unit, long term growth rate reduction necessary to approximate net Book value	0.50%
Reporting unit, percentage of fair value in excess of carrying value if fair value reduced by one half percent	22.00%
Additive Reporting Unit
Goodwill [Line Items]
Goodwill impairment	$ 52,800,000
Additive Reporting Unit | Technology Based Intangible Assets And Customer Relationships
Goodwill [Line Items]
Impairment of intangible assets	4,300,000
Facility Closing
Goodwill [Line Items]
Impairment of intangible assets		7,300,000
Finite-lived intangible assets	$ 0	$ 0
Number of power production facilities closed | facility		2
Valuation Technique, Discounted Cash Flow | Measurement Input, Weighted Average Cost of Capital | Special Alloy Operations Reporting Unit
Goodwill [Line Items]
Goodwill, measurement input	9.00%
Valuation Technique, Discounted Cash Flow | Measurement Input, Terminal Growth Rate | Special Alloy Operations Reporting Unit
Goodwill [Line Items]
Goodwill, measurement input	3.00%
Performance Engineered Products
Goodwill [Line Items]
Number of reporting units | reporting_unit	2
Goodwill	$ 45,900,000	$ 94,900,000	$ 130,900,000
Goodwill impairment	$ 52,800,000	$ 34,600,000
Reporting unit, percentage of fair value in excess of carrying amount	45.00%
Performance Engineered Products | Dynamet
Goodwill [Line Items]
Goodwill	$ 31,900,000
Performance Engineered Products | Latrobe Distribution
Goodwill [Line Items]
Goodwill	$ 14,000,000.0