Note 19 - Selected Quarterly Financial Data (Unaudited) (Detail) - Quarterly Financial Information (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 29, 2012		Sep. 29, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011		Oct. 01, 2011		Jul. 02, 2011		Apr. 02, 2011		Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Net sales	$ 158,794	[1]	$ 172,688	[2]	$ 175,853		$ 160,578	[3]	$ 147,193	[4]	$ 173,987	[5]	$ 176,615		$ 167,160	[6]	$ 667,913	$ 664,955	$ 608,021
Gross profit	59,407	[1]	68,636	[2]	69,562		60,862	[3]	53,526	[4]	68,471	[5]	69,994		64,703	[6]	258,467	256,694	233,872
Operating income	18,019	[1]	30,931	[2]	32,096		25,824	[3]	18,121	[4]	29,574	[5]	35,291		30,918	[6]	106,870	113,904	107,574
Net income (as previously reported)	9,841	[1]	23,998	[2]	23,604		17,889	[3]	15,238	[4]	24,939	[5]	25,269		21,578	[6]	75,332	87,024	78,663
Equity method loss adjustments(g)	2,188	[1],[7]	(1,220)	[2],[7]	(641)	[7]	(326)	[3],[7]		[4],[7]		[5],[7]		[7]		[6],[7]
Net income (restated)	$ 12,029	[1]	$ 22,778	[2]	$ 22,963		$ 17,563	[3]	$ 15,238	[4]	$ 24,939	[5]	$ 25,269		$ 21,578	[6]	$ 75,332	$ 87,024	$ 78,663
Net income per share (as reported):
Basic (in Dollars per share)	$ 0.45	[1]	$ 1.09	[2]	$ 1.08		$ 0.83	[3]	$ 0.71	[4]	$ 1.13	[5]	$ 1.13		$ 0.98	[6]
Diluted (in Dollars per share)	$ 0.44	[1]	$ 1.08	[2]	$ 1.07		$ 0.81	[3]	$ 0.70	[4]	$ 1.12	[5]	$ 1.11		$ 0.96	[6]
Impact of equity method loss adjustments:
Basic (in Dollars per share)	$ 0.10	[1]	$ (0.05)	[2]	$ (0.03)		$ (0.02)	[3]		[4]		[5]				[6]
Diluted (in Dollars per share)	$ 0.09	[1]	$ (0.05)	[2]	$ (0.03)		$ (0.01)	[3]		[4]		[5]				[6]
Net income per share (as restated):
Basic (in Dollars per share)	$ 0.55	[1]	$ 1.04	[2]	$ 1.05		$ 0.81	[3]	$ 0.71	[4]	$ 1.13	[5]	$ 1.13		$ 0.98	[6]	$ 3.45	$ 3.96	$ 3.58
Diluted (in Dollars per share)	$ 0.53	[1]	$ 1.03	[2]	$ 1.04		$ 0.80	[3]	$ 0.70	[4]	$ 1.12	[5]	$ 1.11		$ 0.96	[6]	$ 3.40	$ 3.90	$ 3.52

[1] In the fourth quarter of 2012, the company recorded a $7.3 million charge related to the impairment and equity method losses of Shocking Technology. (See Note 6). The company also recorded a $5.1 million charge related to a pension settlement. (See Note 13).

[2] In the third quarter of 2012, the company recorded $0.5 million charge related to the impairment of the Dnsen, Germany property. (See Note 12). The company also recorded $0.6 million in acquisition charges related to the Accel and Terra Power acquisitions and $0.4 million of non-cash charges related to the step-up of inventory from the Accel acquisition (See Note 2).

[3] In the first quarter of 2012, the company recorded a $0.2 million non-cash charge related to the step-up of inventory from the Selco acquisition (See Note 2).

[4] In the fourth quarter of 2011, the company recorded $0.5 million of non-cash charges related to the step-up of inventory from the Selco A/S acquisition. (See Note 2). The company also recorded a $1.7 million decrease to income tax expense related to a deferred tax asset write-up due to an increase in the statutory rate in China.

[5] In the third quarter of 2011, the company recorded a $2.3 million charge related to asset impairments in Europe.

[6] In the first quarter of 2011, the company recorded $3.7 million of non-cash charges related to the step-up of inventory from the Cole Hersee acquisition. (See Note 2).

[7] Equity method loss adjustments reflects the impact of recording Shocking Technology results for each of the quarters of 2012 on a retroactive basis. (See Note 6).