Summarized Quarterly Data (Unaudited) (Details) (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		Dec. 31, 2010		Oct. 02, 2010		Jul. 03, 2010		Apr. 03, 2010		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Summarized Quarterly Data (Unaudited) [Abstract]
Revenues	$ 226,987		$ 215,988	[1]	$ 228,785	[2]	$ 224,323		$ 253,389	[3]	$ 236,998	[4]	$ 207,478		$ 180,838		$ 896,083		$ 878,703		$ 654,301
Gross profit	67,039		75,356	[1]	92,142	[2]	87,394		98,897	[3]	97,959	[4]	85,483		68,499		321,931		350,838		208,580
Net income	4,308		14,838	[1]	16,565	[2]	12,439		42,494	[3]	112,175	[4]	22,459		13,709		48,150		190,837		16,245
Net income per common share:
Basic	$ 0.03	[5]	$ 0.09	[1],[5]	$ 0.1	[2],[5]	$ 0.08	[5]	$ 0.27	[3],[5]	$ 0.72	[4],[5]	$ 0.14	[5]	$ 0.09	[5]	$ 0.29	[5]	$ 1.22	[5]	$ 0.11
Diluted	$ 0.03	[5]	$ 0.09	[1],[5]	$ 0.1	[2],[5]	$ 0.07	[5]	$ 0.25	[3],[5]	$ 0.69	[4],[5]	$ 0.14	[5]	$ 0.09	[5]	$ 0.28	[5]	$ 1.17	[5]	$ 0.11
Income Tax Beneift			5,811		2,183				4,436		73,367						(10,822)		74,308		(405)
Investment Impairment Recovery																	$ 1,363		$ 1,340		$ (116)

[1] During the third quarter of 2011, the Company recorded a tax benefit of $5,811 resulting from the release of certain liabilities due to the expiration of statute of limitations and the recognition of additional tax credits for 2010 related to R&E spending.

[2] During the second quarter of 2011, the Company recorded a tax benefit of $2,183 resulting from the release of certain liabilities due to the expiration of statute of limitations.

[3] During the fourth quarter of 2010, the Company received $1,340 for the recovery of a previously impaired investment. The Company also recorded a tax benefit of $4,436 primarily due to the recognition of a deferred tax asset related to R&E credits resulting from a change in the tax legislation that was passed at the end of 2010.

[4] During the third quarter of 2010, the Company recorded a tax benefit of $73,367 due to the release of the valuation allowance.

[5] Earnings per share is computed individually for each of the quarters presented; therefore, the sum of the quarterly earnings per share may not necessarily equal the total for the year.