Summary of Quarterly Financial Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Summary of Quarterly Results [Abstract]
Net sales	$ 713,788	$ 683,893	$ 691,875	$ 687,127	$ 686,392	$ 661,412	$ 662,072	$ 682,712	$ 2,776,683	$ 2,692,588	$ 2,701,405
Gross profit on sales	192,793	185,677	187,724	186,768	181,256	182,763	190,322	191,127	752,962	745,468	742,553
Net income	$ 13,896	$ 13,707	$ 12,798	$ 14,766	$ 15,721	$ 11,692	$ 24,179	$ 20,129	$ 55,167	$ 71,721	$ 82,511
Basic and diluted earnings per share	$ 0.51	$ 0.51	$ 0.48	$ 0.55	$ 0.59	$ 0.43	$ 0.90	$ 0.75	$ 2.05	$ 2.67	$ 3.07