Common Shares (Details 2)	Jul. 16, 2012 $ / shares shares
Series A Preferred Stock
Shareholder Rights Plan
Par value (in dollars per share)	$ 0.001
Right To Purchase Series Junior Participating Preferred Shares1
Shareholder Rights Plan
Number of purchase rights issued per Common Share	$ 1
Number of shares each Right entitled to purchase | shares	0.001
Exercise price (in dollars per share)	$ 80.00
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
Conditions of rights issuance, business days following Commencement or Announcement to make an offer	10 days
Right To Purchase Series Junior Participating Preferred Shares1 | Maximum
Shareholder Rights Plan
Conditions of rights issuance, number of days following announcement	20 days