Acquisitions and Divestitures - Pro Forma Disclosure (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2010
Magellan as Reported
Sales	$ 1,970	$ 4,805	$ 3,202	$ 3,735	$ 5,149	$ 4,867	$ 4,461	$ 3,699	$ 13,712		$ 18,176		$ 28,525
Net income (loss) attributable to Magellan Petroleum Corporation	34,705	(4,590)	(4,557)	940	(26,873)	(84)	(2,099)	(3,376)	26,498		(32,432)		(1,446)
Net income (loss) per basic share outstanding (dollars per share)	$ 0.64	$ (0.09)	$ (0.08)	$ 0.02	$ (0.51)		$ (0.04)	$ (0.06)	$ 0.49		$ (0.62)		$ (0.03)
Net income (loss) per diluted share outstanding (dollars per share)	$ 0.64	$ (0.09)	$ (0.08)	$ 0.02	$ (0.51)		$ (0.04)	$ (0.06)	$ 0.49		$ (0.62)		$ (0.03)
Santos Sales Agreement
Pro Forma Acquisition
Pro Forma Acquisition, Sales									1,025	[1]	4,492	[1]
Pro Forma Acquisition, Net income (loss) attributable to Magellan Petroleum Corporation									(223)	[1]	2,471	[1]
Pro Forma Disposition
Pro Forma Disposition, Sales									(5,891)	[2]	(8,813)	[2]
Pro Forma Disposition, Net income (loss) attributable to Magellan Petroleum Corporation									835	[2]	(1,144)	[2]
Pro Forma Combined
Pro Forma Combined, Sales									8,846		13,855
Pro Forma Combined, Net income (loss) attributable to Magellan Petroleum Corporation									$ 27,110		$ (31,105)
Pro Forma Combined, Net income per basic share outstanding									$ 0.51		$ (0.59)
Pro Forma Combined, Net income per diluted share outstanding									$ 0.50		$ (0.59)

[1] Reflects the pro forma results from operations related to the Palm Valley Interests and the Dingo Interests.

[2] Reflects the pro forma results from operations related to the Mereenie Interests.