Stock Plans (Details 1) (Employee Stock Purchase Plan [Member], USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee Stock Purchase Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Maximum employee contribution to ESPP, monetary	$ 25
Maximum employee contribution to ESPP, percent of base compensation	10.00%
Common Stock Discount Purchase Price	95.00%
Shares Available Under Employee Stock Purchase Plan	4,550,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans	27,949	31,874	41,791
Proceeds from Stock Plans	$ 646,000	$ 670,000	$ 733,000
Number Of Shares Available Under Employee Stock Purchase Plan	336,204