Sales By Product Category Information (Detail) - Sales - Product Concentration Risk	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Product Information [Line Items]
Sales	100.00%	100.00%	100.00%
Supplies
Product Information [Line Items]
Sales	45.20%	44.40%	43.60%
Technology
Product Information [Line Items]
Sales	38.90%	40.20%	41.20%
Furniture And Other
Product Information [Line Items]
Sales	15.90%	15.40%	15.20%