Significant Accounting Policies Schedule of Comprehensive Income (Loss) (Details) (USD $) In Thousands, 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
Accounting Policies [Abstract]
Net income (loss)	$ 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
Other comprehensive (loss) income:
Net unrealized loss on available for sale investments													(3)	(14)	(306)
Net unrealized (loss) gain on pension obligations													(337)	(242)	64
Comprehensive income													$ 47,810	$ 190,581	$ 16,003

[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.