Business Segments - Narrative (Details) - segment	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2016
Segment Reporting [Abstract]
Number of reportable segments			2
Customer Concentration Risk | Net Sales | Alcoa
Concentration Risk [Line Items]
Concentration risk		14.00%		14.00%
Customer Concentration Risk | Net Sales | Arconic
Concentration Risk [Line Items]
Concentration risk	17.00%		15.00%
Customer Concentration Risk | Accounts Receivable | Arconic
Concentration Risk [Line Items]
Concentration risk			23.00%
Customer Concentration Risk | Accounts Receivable | Alcoa, Inc. and Precision Castparts Corporation
Concentration Risk [Line Items]
Concentration risk					22.00%