Revenues (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 26, 2021	Mar. 27, 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue	$ 18,005	$ 16,712
Deferred revenue, current	12,669	11,956
Deferred revenue, noncurrent	$ 5,300	$ 4,700
Minimum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Payment term	15 days
Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Payment term	45 days
Tire Road Hazard Warranty [Member] | Minimum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognition, contract term	21 months
Tire Road Hazard Warranty [Member] | Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognition, contract term	36 months