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Acquisitions and Divestitures - Purchase Price Allocation and Other Disclosures (Details)
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12 Months Ended | 0 Months Ended | 12 Months Ended | ||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Jun. 30, 2013
USD ($)
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Jun. 30, 2012
USD ($)
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Jun. 30, 2013
AUD
|
Sep. 02, 2011
USD ($)
|
Sep. 06, 2011
Lease Purchase and Sale and Participation Agreement with VAALCO Energy
USD ($)
|
Jun. 30, 2013
Santos Sales Agreement
USD ($)
|
Jun. 30, 2013
Nautilus Purchase and Sale Agreement (PSA)
USD ($)
|
Jun. 30, 2012
Nautilus Purchase and Sale Agreement (PSA)
USD ($)
|
Sep. 23, 2011
Nautilus Purchase and Sale Agreement (PSA)
|
Sep. 02, 2011
Nautilus Purchase and Sale Agreement (PSA)
USD ($)
|
Sep. 02, 2011
NT non-controlling interest in NP
USD ($)
|
Sep. 02, 2011
NT working interest in Poplar
USD ($)
|
Sep. 02, 2011
ER non-controlling interest in NP
USD ($)
|
Sep. 02, 2011
Maximum
Nautilus Purchase and Sale Agreement (PSA)
USD ($)
|
Sep. 02, 2011
J. Thomas Wilson
Nautilus Purchase and Sale Agreement (PSA)
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May 25, 2012
Mereenie Operating Joint Venture
Santos Sales Agreement
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May 25, 2012
Mereenie Pipeline Joint Venture
Santos Sales Agreement
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May 25, 2012
Palm Valley Joint Venture
Santos Sales Agreement
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May 25, 2012
Dingo Joint Venture
Santos Sales Agreement
|
Jul. 22, 2011
Evans Shoal
AUD
|
Jun. 30, 2011
Evans Shoal
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| Disposal Group, Other Information [Abstract] | |||||||||||||||||||||||||||||
| Ownership percentage | 40.00% | ||||||||||||||||||||||||||||
| Refund received for deposit | 10,000,000 | ||||||||||||||||||||||||||||
| Ownership interest sold | 35.00% | 35.00% | |||||||||||||||||||||||||||
| Ownership interest sold by third party | 48.00% | 66.00% | |||||||||||||||||||||||||||
| Contingent consideration arrangement, maximum | 17,500,000.0 | ||||||||||||||||||||||||||||
| Written off related to sale of business unit | 0 | 2,521,000 | |||||||||||||||||||||||||||
| Working interest sold | 65.00% | ||||||||||||||||||||||||||||
| Disposal Group, Cost of Disposed Entity [Abstract] | |||||||||||||||||||||||||||||
| Net purchase price per Santos SA | 5,000,000 | 25,493,000 | |||||||||||||||||||||||||||
| Purchase price adjustments | 1,138,000 | ||||||||||||||||||||||||||||
| Total | 26,631,000 | ||||||||||||||||||||||||||||
| Disposal Group, Consideration Received Allocation [Abstract] | |||||||||||||||||||||||||||||
| Proved oil and gas properties (Palm Valley) | 3,403,000 | ||||||||||||||||||||||||||||
| Unproved oil and gas properties (Dingo) | 2,957,000 | ||||||||||||||||||||||||||||
| Land, buildings, and equipment (Palm Valley) | 370,000 | ||||||||||||||||||||||||||||
| Total allocation of the fair value received | 6,730,000 | ||||||||||||||||||||||||||||
| Mereenie liabilities given up, net (including basis in properties exchanged and allocated goodwill) | 2,805,000 | ||||||||||||||||||||||||||||
| Net book value allocated to Deep Intervals | (829,000) | ||||||||||||||||||||||||||||
| Transaction costs | (162,000) | ||||||||||||||||||||||||||||
| Gain on sale of assets | 4,009,000 | 36,166,000 | |||||||||||||||||||||||||||
| Business Acquisition, Cost of Acquired Entity [Abstract] | |||||||||||||||||||||||||||||
| Cash consideration | 4,000,000 | [1] | 4,000,000 | 1,920,000 | [1] | 823,000 | [1] | 1,257,000 | [1] | ||||||||||||||||||||
| Share consideration | 1,822,000 | [1],[2] | 2,000,000 | 907,000 | [1],[2] | 389,000 | [1],[2] | 526,000 | [1],[2] | ||||||||||||||||||||
| Fair value of contingent consideration payable | 4,151,000 | [1] | 1,993,000 | [1] | 854,000 | [1] | 1,304,000 | [1] | 5,000,000 | ||||||||||||||||||||
| Total | 9,973,000 | [1] | 4,820,000 | [1] | 2,066,000 | [1] | 3,087,000 | [1] | |||||||||||||||||||||
| Share Consideration Paid, Par Value | $ 0.01 | ||||||||||||||||||||||||||||
| Share Consideration Paid, Shares | 1,182,742 | ||||||||||||||||||||||||||||
| Related Party Interest in Cash Consideration Paid | 52.00% | ||||||||||||||||||||||||||||
| Contingent consideration payable | 3,940,000 | 4,072,000 | 3,940,000 | 4,072,000 | |||||||||||||||||||||||||
| Share Consideration Paid, Per Share | $ 1.54 | ||||||||||||||||||||||||||||
| Business Acquisition, Purchase Price Allocation [Abstract] | |||||||||||||||||||||||||||||
| Oil and gas assets (proved) | 1,462,000 | ||||||||||||||||||||||||||||
| Oil and gas assets - Deep Intervals (unproved) | 679,000 | ||||||||||||||||||||||||||||
| ARO liability | (75,000) | ||||||||||||||||||||||||||||
| Total | $ 2,066,000 | ||||||||||||||||||||||||||||
| Share price | $ 1.54 | ||||||||||||||||||||||||||||
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