Common Shares (Details 2) (USD $)				0 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jul. 16, 2012 Series A Preferred Stock	Jul. 16, 2012 Series A Preferred Stock Rights	Jul. 16, 2012 Series A Preferred Stock Rights Maximum
Shareholder Rights Plan
Number of purchase rights issued per Common Share				$ 1
Number of shares each Right entitled to purchase				0.001
Par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Exercise price (in dollars per share)				$ 70.00
Minimum percentage holding of common shares for exercising preferred share purchase rights				10.00%
Conditions of rights issuance, number of days following announcement				10 days	20 days