Share-based Compensation (Details 3)	12 Months Ended			1 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2012 1995 Plan	Dec. 31, 2012 2001 Plan	Apr. 30, 2012 2005 Plan	May 31, 2008 2005 Plan	Dec. 31, 2012 2005 Plan
Share-Based Compensation
Number of option plans	3
Increase in the number of shares available for issuance				2,500,000	5,000,000
Number of shares originally available for issuance	20,350,000	4,500,000	500,000			15,350,000
Shares outstanding	15,656,250	4,500,000	500,000			10,656,250
Shares available for grant	4,693,750