Quarterly Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Jan. 03, 2015		Sep. 27, 2014		Jun. 28, 2014		Mar. 29, 2014		Dec. 28, 2013		Sep. 28, 2013		Jun. 29, 2013		Mar. 30, 2013		Jan. 03, 2015	Dec. 28, 2013		Dec. 29, 2012
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 434,995		$ 404,289		$ 424,776		$ 372,478		$ 377,420		$ 360,013		$ 363,801		$ 327,451		$ 1,636,538	$ 1,428,685		$ 1,038,174
Gross Profit	169,055		162,380		166,174		142,976		150,731		141,438		136,574		121,268		640,585	550,011		402,989
Income from operations	82,295		86,465		75,739		55,933		74,454		67,488		60,325		42,195		300,432	244,462		188,084	[1]
Net earnings	$ 51,749		$ 59,713		$ 48,405		$ 33,445		$ 49,921		$ 40,942		$ 37,163		$ 25,902		$ 193,312	$ 153,928		$ 120,697
Basic earnings per share (usd per share)	$ 0.91	[2]	$ 1.05	[2]	$ 0.85	[2]	$ 0.59	[2]	$ 0.89	[2]	$ 0.73	[2]	$ 0.67	[2]	$ 0.47	[2]	$ 3.41	$ 2.76	[2]	$ 2.22
Diluted earnings per share (usd per share)	$ 0.91	[2]	$ 1.05	[2]	$ 0.85	[2]	$ 0.59	[2]	$ 0.87	[2]	$ 0.73	[2]	$ 0.67	[2]	$ 0.47	[2]	$ 3.40	$ 2.74	[2]	$ 2.20

[1] Non-operating expenses are not allocated to the reportable segments. Non-operating expenses consist of interest expense and deferred financing amortization, foreign exchange gains and losses and other income and expense items outside of income from operations.

[2] Sum of quarters may not equal the total for the year due to changes in the number of shares outstanding during the year.