Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jun. 25, 2016	Jul. 01, 2017	Jun. 25, 2016
Consolidated Statements of Income [Abstract]
Net sales	$ 876,569	$ 730,433	$ 1,728,798	$ 1,468,637
Cost of sales, including warehousing and distribution expenses	636,690	528,495	1,259,123	1,059,588
Gross profit on sales	239,879	201,938	469,675	409,049
Operating, general and administrative expenses	212,161	177,881	421,707	353,723
Income from operations	27,718	24,057	47,968	55,326
Investment income and interest expense	412	682	1,236	1,319
Income before provision for income taxes	28,130	24,739	49,204	56,645
Provision for income taxes	9,655	9,474	18,893	21,252
Net income	$ 18,475	$ 15,265	$ 30,311	$ 35,393
Weighted-average shares outstanding, basic and diluted	26,898,443	26,898,443	26,898,443	26,898,443
Cash dividends per share	$ 0.30	$ 0.30	$ 0.60	$ 0.60
Basic and diluted earnings per share	$ 0.69	$ 0.57	$ 1.13	$ 1.32