Fair Value Measurements (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended
	Jun. 30, 2010	Oct. 01, 2011	Apr. 02, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	May 31, 2011
Fair Value Measurements [Abstract]
Proceeds from redemption of auction rate securities	$ 1,650,000
Changes in unrealized gains and losses on available-for- sale securities, net of tax, recorded in accumulated other comprehensive income (loss)	200,000			(385,000)	(406,000)	737,000
Trading securities								2,550,000
Auction rate securities		0	450,000
Permanent write-down		326,000
Loss on sale of auction rate securities			36,000
Decline in other than temporarily impaired securities							4,374,000
Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount							4,374,000
Proceeds from sale of auction rate securities		$ 107,000