Other liabilities (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		113 Months Ended		9 Months Ended		1 Months Ended	9 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2013	Nov. 30, 2012	Aug. 31, 2013 Approximations [Member]	Aug. 31, 2013 Number of RSU's [Member]	Jun. 30, 2013 Officers [Member]	Aug. 31, 2013 Officers [Member] Number of RSU's [Member]
Units granted								1,000,000		1,000,000
Stock-based compensation	$ 755,000	$ 1,987,000	$ 6,868,000	$ 7,481,000	$ 17,393,000		$ 1,300,000
Deferred Compensation Share-based Arrangements, Liability, Current							500,000
Deferred Compensation Share-based Arrangements, Liability, Classified, Noncurrent	235,000		235,000		235,000	0	200,000
Units vested								(333,331)	333,333
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures									150,000
Payments for Settlement of Units Vested									$ 300,000