Significant Customers (Details)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Significant customers
Concentration percentage, disclosure threshold	5.00%
Customers | Sales
Significant customers
Concentration percentage	36.90%	45.00%
Customers | Receivables
Significant customers
Concentration percentage	34.20%	18.40%
Customers | Receivables | Customer 1
Significant customers
Concentration percentage	11.50%
Customers | Receivables | Customer 2
Significant customers
Concentration percentage	8.80%	6.80%
Customers | Receivables | Customer 3
Significant customers
Concentration percentage	8.60%
Customers | Receivables | Customer 4
Significant customers
Concentration percentage	5.30%
Customers | Receivables | Customer 5
Significant customers
Concentration percentage		11.60%
Precision Components Group | Customers | Sales | Customer 1
Significant customers
Concentration percentage	10.50%	10.60%
Precision Components Group | Customers | Sales | Customer 2
Significant customers
Concentration percentage	9.90%	7.20%
Precision Components Group | Customers | Sales | Customer 4
Significant customers
Concentration percentage	7.10%	13.80%
Stamping Group | Customers | Sales | Customer 3
Significant customers
Concentration percentage	9.40%	6.70%
Stamping Group | Customers | Sales | Customer 5
Significant customers
Concentration percentage		6.70%