Revenue - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 25, 2017	Jun. 30, 2018	Jun. 25, 2017
Revenue From Contract With Customers [Line Items]
Revenue, performance obligation, description of timing			Delivery periods of less than a month
Revenue, performance obligation, description of payment terms			Customer payment is generally due 40-60 days after shipment
Deferred revenue, revenue recognized	$ 2.1	$ 1.8	$ 3.7	$ 3.5
Contract with customer, timing of satisfaction of performance obligation and payment			Contract terms are substantially less than a year (generally less than one month)
Tooling Reimbursement [Member]
Revenue From Contract With Customers [Line Items]
Deferred revenue, revenue recognized	2.1		$ 3.7
Price Adjustments [Member]
Revenue From Contract With Customers [Line Items]
Deferred revenue, revenue recognized	$ 0.2		$ 1.9