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
	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016
Segment Data
Net Sales:	$ 389.0	$ 455.6
Operating Income (Loss):	1.4	24.8
Depreciation and Amortization:	28.9	29.9
Capital Expenditures:	26.6	29.9
Total Assets:	2,814.1		$ 2,794.3
Corporate
Segment Data
Operating Income (Loss):	(13.8)	(12.0)
Depreciation and Amortization:	0.8	0.9
Capital Expenditures:	7.5	1.1
Total Assets:	166.0		151.3
Intersegment
Segment Data
Net Sales:	(4.6)	(8.5)
Operating Income (Loss):	0.1	0.9
Pension earnings, interest and deferrals	(7.1)	(4.8)
Depreciation and Amortization:	(0.4)	(0.2)
Capital Expenditures:	(0.1)	0.0
Total Assets:	(21.3)		(29.3)
Specialty Alloys Operations | Operating
Segment Data
Net Sales:	315.1	372.6
Operating Income (Loss):	25.0	41.1
Depreciation and Amortization:	23.4	23.5
Capital Expenditures:	14.7	19.7
Total Assets:	2,254.0		2,256.5
Performance Engineered Products | Operating
Segment Data
Net Sales:	78.5	91.5
Operating Income (Loss):	(2.8)	(0.4)
Depreciation and Amortization:	5.1	5.7
Capital Expenditures:	4.5	$ 9.1
Total Assets:	$ 415.4		$ 415.8