Significant Acounting Policies (Details)	3 Months Ended		6 Months Ended
	Jul. 11, 2020	Jul. 13, 2019	Jul. 11, 2020	Jul. 13, 2019
Revenue from External Customer [Line Items]
Percentage Of Sales By Product Group	100.00%	100.00%	100.00%	100.00%
Parts and Batteries [Member]
Revenue from External Customer [Line Items]
Percentage Of Sales By Product Group	66.00%	67.00%	66.00%	66.00%
Accessories and Chemicals [Member]
Revenue from External Customer [Line Items]
Percentage Of Sales By Product Group	22.00%	21.00%	21.00%	21.00%
Engine Maintenance [Member]
Revenue from External Customer [Line Items]
Percentage Of Sales By Product Group	11.00%	11.00%	12.00%	12.00%
Other [Member]
Revenue from External Customer [Line Items]
Percentage Of Sales By Product Group	1.00%	1.00%	1.00%	1.00%