Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Consolidated Statements of Income [Abstract]
Net sales	$ 3,136,720	$ 2,876,748	$ 2,776,683
Cost of sales, including warehousing and distribution expenses	2,264,565	2,090,016	2,023,721
Gross profit on sales	872,155	786,732	752,962
Operating, general and administrative expenses	773,830	695,953	671,587
Income from operations	98,325	90,779	81,375
Investment income and interest expense	2,457	1,552	2,287
Gain on bargain purchase	23,879	0	0
Income before provision for income taxes	124,661	92,331	83,662
Provision for income taxes	37,499	33,001	29,281
Net income	$ 87,162	$ 59,330	$ 54,381
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	$ 3.24	$ 2.21	$ 2.02