Commitments And Contingencies (Cumulative Letters Of Credit) (Details)	Sep. 30, 2011 CAD	Sep. 30, 2011 March 1, 2012 USD ($)		Sep. 30, 2011 March 1, 2012 CAD		Sep. 30, 2011 October 1, 2012 USD ($)		Sep. 30, 2011 October 1, 2012 CAD		Sep. 30, 2011 July 1, 2013 CAD		Sep. 30, 2011 July 1, 2013 USD ($)		Sep. 30, 2011 October 1, 2013 CAD		Sep. 30, 2011 October 1, 2013 USD ($)
Line of Credit Facility [Line Items]
Cumulative letters of credit		$ 65,124,000	[1]	68,264,000	[1]	$ 104,764,000	[1]	109,816,000	[1]	148,400,000	[1]	$ 141,574,000	[1]	257,400,000	[1]	$ 245,560,000	[1]
Letters of credit outstanding	32,600,000

[1] A letter of credit for C$32.6 million is outstanding for the NGTL Project as of September 30, 2011.