QUARTERLY DATA (UNAUDITED) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2011		Oct. 01, 2011		Jul. 02, 2011		Apr. 02, 2011		Jan. 01, 2011		Oct. 02, 2010		Jul. 03, 2010		Apr. 03, 2010		Dec. 31, 2011		Jan. 01, 2011		Jan. 02, 2010
Quarterly Financial Information [Line Items]
Net sales	$ 243,760		$ 218,720		$ 210,855		$ 182,572		$ 207,233		$ 177,793		$ 173,412		$ 160,683		$ 855,907	[1]	$ 719,121	[1]	$ 646,629	[1]
Gross profit	99,652		87,318		85,337		71,830		83,093		70,687		69,424		63,473		344,137		286,677		250,628
Income from operations	44,912		37,186		35,248		31,364		34,613		32,011		29,729		26,435		148,710	[1]	122,788	[1]	111,441	[1]
Net earnings	$ 34,559		$ 23,461		$ 19,628		$ 17,825		$ 20,994		$ 20,602		$ 17,509		$ 13,762		$ 95,473		$ 72,867		$ 61,156
Basic earnings per share	$ 1.92	[2]	$ 1.30	[2]	$ 1.09	[2]	$ 1.00	[2]	$ 1.18	[2]	$ 1.16	[2]	$ 0.98	[2]	$ 0.78	[2]	$ 5.30	[2]	$ 4.09	[2]	$ 3.47
Diluted earnings per share	$ 1.87	[2]	$ 1.26	[2]	$ 1.06	[2]	$ 0.97	[2]	$ 1.13	[2]	$ 1.13	[2]	$ 0.96	[2]	$ 0.74	[2]	$ 5.15	[2]	$ 3.97	[2]	$ 3.29

[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 outstandingduring the year.