Significant Customers (Details)	3 Months Ended
	Sep. 30, 2018	Oct. 01, 2017
Significant customers
Concentration percentage, disclosure threshold	5.00%	5.00%
Customers | Sales
Significant customers
Concentration percentage	42.70%	37.00%
Customers | Receivables
Significant customers
Concentration percentage	35.70%	34.20%
Customers | Receivables | Customer 1
Significant customers
Concentration percentage	10.50%	8.60%
Customers | Receivables | Customer 2
Significant customers
Concentration percentage	9.40%	8.80%
Customers | Receivables | Customer 3
Significant customers
Concentration percentage	5.80%	11.50%
Customers | Receivables | Customer 4
Significant customers
Concentration percentage	10.00%
Customers | Receivables | Customer 6
Significant customers
Concentration percentage		5.30%
Precision Components Group | Customers | Sales | Customer 1
Significant customers
Concentration percentage	13.10%	6.00%
Precision Components Group | Customers | Sales | Customer 3
Significant customers
Concentration percentage	10.60%	5.50%
Precision Components Group | Customers | Sales | Customer 4
Significant customers
Concentration percentage	8.20%	10.20%
Stamping Group | Customers | Sales | Customer 2
Significant customers
Concentration percentage	10.80%	9.10%
Stamping Group | Customers | Sales | Customer 5
Significant customers
Concentration percentage		6.20%