Revenue (Schedule Of Disaggregated Revenue By Product Group) (Details) - USD ($) $ in Thousands	3 Months Ended
Jun. 29, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 317,063	$ 295,811
Brakes [Member]
Disaggregation of Revenue [Line Items]
Revenue	46,776	42,748
Exhaust [Member]
Disaggregation of Revenue [Line Items]
Revenue	6,953	7,076
Steering [Member]
Disaggregation of Revenue [Line Items]
Revenue	26,232	25,059
Tires [Member]
Disaggregation of Revenue [Line Items]
Revenue	154,065	141,103
Maintenance [Member]
Disaggregation of Revenue [Line Items]
Revenue	82,174	79,010
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 863	$ 815

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration