Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Consolidated Statements of Income [Abstract]
Net sales	$ 3,466,807	$ 3,136,720	$ 2,876,748
Cost of sales, including warehousing and distribution expenses	2,540,348	2,264,565	2,090,016
Gross profit on sales	926,459	872,155	786,732
Operating, general and administrative expenses	850,034	773,830	695,953
Income from operations	76,425	98,325	90,779
Investment income and interest expense	2,598	2,457	1,552
Gain on bargain purchase	0	23,879	0
Income before provision for income taxes	79,023	124,661	92,331
Provision for income taxes	(19,391)	37,499	33,001
Net income	$ 98,414	$ 87,162	$ 59,330
Weighted-average shares outstanding, basic and diluted	26,898,443	26,898,443	26,898,443
Cash dividends per share	$ 1.20	$ 1.20	$ 1.20
Basic and diluted earnings per share	$ 3.66	$ 3.24	$ 2.21