Note 18 - Selected Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Information (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
Quarterly Financial Information [Abstract]
Net sales	$ 206,620	[1]	$ 217,608	[2]	$ 220,908	[3]	$ 206,859	[4]	$ 198,129	[5]	$ 201,040	[6]	$ 187,766	[7]	$ 170,918	[7],[8]	$ 851,995	$ 757,853	$ 667,913
Gross profit	75,559	[1]	87,380	[2]	82,995	[3]	78,494	[4]	77,109	[5]	80,960	[6]	73,557	[7]	64,606	[7],[8]	324,428	296,232	258,467
Operating income	26,391	[1]	40,130	[2]	33,719	[3]	33,590	[4]	32,823	[5]	37,559	[6]	31,382	[7]	28,117	[7],[8]	133,830	129,881	106,870
Net income (as previously reported)	19,511	[1]	29,940	[2]	24,578	[3]	25,389	[4]	23,658	[5]	26,990	[6]	26,648	[7]	14,794	[7],[8]	99,418	88,784	75,332
Tax adjustment(d)		[1],[4]		[2],[4]		[3],[4]		[4]		[4],[5]		[4],[6]		[4],[7]	(3,306)	[4],[7],[8]
Net income (Q1 2013 as restated)	$ 19,511	[1]	$ 29,940	[2]	$ 24,578	[3]	$ 25,389	[4]	$ 23,658	[5]	$ 26,990	[6]	$ 26,648	[7]	$ 11,488	[7],[8]	$ 99,418	$ 88,784	$ 75,332
Net income per share (as reported):
Basic	$ 0.86	[1]	$ 1.33	[2]	$ 1.09	[3]	$ 1.13	[4]	$ 1.05	[5]	$ 1.20	[6]	$ 1.19	[7]	$ 0.67	[7],[8]
Diluted	$ 0.86	[1]	$ 1.32	[2]	$ 1.08	[3]	$ 1.12	[4]	$ 1.04	[5]	$ 1.19	[6]	$ 1.18	[7]	$ 0.66	[7],[8]
Impact of tax adjustment:
Basic		[1]		[2]		[3]		[4]		[5]		[6]		[7]	$ (0.15)	[7],[8]
Diluted		[1]		[2]		[3]		[4]		[5]		[6]		[7]	$ (0.15)	[7],[8]
Net income per share (Q1 2013 as restated):
Basic	$ 0.86	[1]	$ 1.33	[2]	$ 1.09	[3]	$ 1.13	[4]	$ 1.05	[5]	$ 1.20	[6]	$ 1.19	[7]	$ 0.52	[7],[8]	$ 4.41	$ 3.98	$ 3.45
Diluted	$ 0.86	[1]	$ 1.32	[2]	$ 1.08	[3]	$ 1.12	[4]	$ 1.04	[5]	$ 1.19	[6]	$ 1.18	[7]	$ 0.51	[7],[8]	$ 4.37	$ 3.94	$ 3.40

[1] In the fourth quarter of 2014, the company recorded $2.2 million in charges related to severance and to the company's reorganization of its internal legal structure toenable the up-streaming of cash to the U.S. The company also recorded $0.3 million in acquisition costs and $0.3 million in impairment costs.

[2] In the third quarter of 2014, the company recorded $1.1 million in charges related to the company's reorganization of its internal legal structure, as noted above.

[3] In the second quarter of 2014, the company recorded a $1.4 million non-cash charge related to the step-up of inventory from the SymCom acquisition (See Note 2), $2.0 million in severance charges and $0.2 million in acquisition costs.

[4] In the first quarter of 2014, the company recorded a $1.4 million non-cash charge related to the step-up of inventory from the SymCom acquisition (See Note 2).

[5] In the fourth quarter of 2013, the company recorded a $2.8 million charge to income tax expense related to the company's impairment of its investment in Shocking Technologies in the fourth quarter of 2012 (See Note 6). The company also recorded a $0.5 million non-cash credit related to the step-up of inventory from the Hamlin acquisition (See Note 2) and $0.2 million in acquisition expenses for the Hamlin acquisition.

[6] In the third quarter of 2013, the company recorded a $0.3 million non-cash charge related to the step-up of inventory from the Hamlin acquisition (See Note 2). Thecompany also recorded $0.3 million in acquisition charges related to the Hamlin acquisition.

[7] In the second quarter of 2013, the company recorded a $1.7 million non-cash charge related to the step-up of inventory from the Hamlin acquisition (See Note 2).The company also recorded $1.2 million in acquisition charges related to the Hamlin acquisition.

[8] In the first quarter of 2013, the company recorded a $10.7 million charge related to the impairment of Shocking Technologies. Additionally, the company restated netincome for a $3.3 million charge to income tax expense related to the company's investment in Shocking Technologies (See Note 6).