Quarterly Results of Operations - Schedule of Quarterly Financial Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended								12 Months Ended
	Sep. 29, 2012	Dec. 31, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Oct. 01, 2011	Jul. 02, 2011	Apr. 02, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Results Of Operations [Line Items]
Net sales of tangible products		$ 241,257	$ 239,786	$ 234,708	$ 232,476	$ 235,714	$ 241,686	$ 232,762	$ 226,120	$ 948,227	$ 936,282	$ 849,530
Revenue from services and software		11,922	12,251	12,369	11,399	11,594	11,652	12,779	11,181	47,941	47,206	44,829
Total net sales		253,179	252,037	247,077	243,875	247,308	253,338	245,541	237,301	996,168	983,488	894,359
Cost of sales of tangible products		121,869	118,751	119,980	119,033	118,792	122,529	117,732	110,781	479,633	469,834	450,630
Cost of sales services and software		6,850	6,362	6,720	4,959	6,996	7,256	6,111	6,522	24,891	26,885	22,954
Total cost of sales		128,719	125,113	126,700	123,992	125,788	129,785	123,843	117,303	504,524	496,719	473,584
Gross Profit		124,460	126,924	120,377	119,883	121,520	123,553	121,698	119,998	491,644	486,769	420,775
Selling and marketing		33,313	32,321	32,158	32,114	36,377	31,942	30,950	28,528	129,906	127,797	112,365
Research and development		22,605	22,007	22,336	20,416	23,174	22,584	22,487	21,681	87,364	89,926	82,575
General and administrative		20,964	22,481	24,402	24,320	18,973	18,978	20,688	22,706	92,167	81,345	73,229
Amortization of intangible assets		1,463	1,670	770	770	806	843	836	835	4,673	3,320	3,211
Acquisition costs		1,037	566	1,252	254	116	188	0	0	3,109	304	0
Exit and restructuring costs		960	0	0	0	(49)	138	66	1,886	960	2,041	2,262
Asset impairment charge	9,114	0	9,114	0	0					9,114	0	0
Total operating expenses		80,342	88,159	80,918	77,874	79,397	74,673	75,027	75,636	327,293	304,733	272,560
Operating income		44,118	38,765	39,459	42,009	42,123	48,880	46,671	44,362	164,351	182,036	148,215
Investment income		526	541	826	592	594	134	656	560	2,485	1,944	2,678
Foreign exchange (loss)		(5)	(514)	(80)	(342)	(706)	(173)	(833)	(294)	(941)	(2,006)	(169)
Other, net		(577)	(294)	(486)	(364)	(899)	(859)	(243)	(254)	(1,721)	(2,255)	(1,117)
Total other income (loss)		(56)	(267)	260	(114)	(1,011)	(898)	(420)	12	(177)	(2,317)	1,392
Income from continuing operations before income taxes		44,062	38,498	39,719	41,895	41,112	47,982	46,251	44,374	164,174	179,719	149,607
Income taxes		9,263	11,917	9,366	11,731	8,253	13,795	13,082	14,246	42,277	49,376	44,993
Income from continuing operations		34,799	26,581	30,353	30,164	32,859	34,187	33,169	30,128	121,897	130,343	104,614
Income (loss) from discontinued operations, net of tax		191	516	300	0	2,185	10,814	(205)	31,506	1,007	44,300	(2,836)
Net income		$ 34,990	$ 27,097	$ 30,653	$ 30,164	$ 35,044	$ 45,001	$ 32,964	$ 61,634	$ 122,904	$ 174,643	$ 101,778
Income from continuing operations		$ 0.69	$ 0.52	$ 0.58	$ 0.58	$ 0.63	$ 0.64	$ 0.60	$ 0.54	$ 2.36	$ 2.42	$ 1.83
Income from discontinued operations		$ 0.00	$ 0.01	$ 0.01	$ 0.00	$ 0.04	$ 0.20	$ 0.00	$ 0.57	$ 0.02	$ 0.82	$ (0.05)
Net Income		$ 0.69	$ 0.53	$ 0.59	$ 0.58	$ 0.67	$ 0.84	$ 0.60	$ 1.11	$ 2.38	$ 3.24	$ 1.78
Income from continuing operations		$ 0.68	$ 0.51	$ 0.58	$ 0.58	$ 0.63	$ 0.64	$ 0.60	$ 0.54	$ 2.35	$ 2.40	$ 1.82
Income from discontinued operations		$ 0.00	$ 0.01	$ 0.01	$ 0.00	$ 0.04	$ 0.20	$ 0.00	$ 0.56	$ 0.02	$ 0.82	$ (0.05)
Net Income		$ 0.68	$ 0.52	$ 0.59	$ 0.58	$ 0.67	$ 0.84	$ 0.60	$ 1.10	$ 2.37	$ 3.22	$ 1.77
Basic weighted average shares outstanding		50,968	51,566	51,771	51,998	52,108	53,339	54,546	55,353	51,566	53,854	57,143
Diluted weighted average and equivalent shares outstanding		51,262	51,809	52,030	52,301	52,354	53,628	54,958	55,774	51,843	54,191	57,428