Capital Stock (Schedule of Issuances and Forfeitures of Common Shares) (Details) - shares
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares of common stock issued pursuant to PBUs vested, net of forfeitures 497,636 472,189
Stock options exercised   7,500
Restricted shares    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares of restricted common stock granted 1,426,604 601,473
Shares of restricted common stock vested 1,422,670 1,915,242
Shares of restricted common stock surrendered upon vesting/exercise [1] 413,333 612,612
Shares of restricted common stock forfeited 119,499 47,398
[1] Represents shares of common stock forfeited in connection with the payment of estimated withholding taxes on shares of restricted common stock that vested and with the payment of the exercise price and estimated withholding taxes on option exercises during the period.