Oil and Gas Properties - Additional Information (Details)	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Oil and Gas Property [Line Items]
Lease period	15 years
Number of drill wells, Maximum	68
Number of drill wells, Minimum	44
Number of sections	68
Seismic line	25
Number of drill wells for future oil production	10	10
Minimum | Undrilled Section
Oil and Gas Property [Line Items]
Seismic line	2