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Supplemental Disclosures about Oil and Natural Gas Producing Properties (unaudited) (Details 2) | 12 Months Ended |
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Jun. 30, 2013 item Boe | Jun. 30, 2012 Boe | Jun. 30, 2011 Boe | Jun. 30, 2010 Boe
Estimated Net Quantities of Proved Oil and Natural Gas Reserves |  |  |  |
Period on the basis of which reserve volumes and values are determined | 12 months |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Balance at the beginning of the period (in BOE) | 13,441,116 | 13,847,462 | 12,418,256 |
Revisions of previous estimates (in BOE) | 2,806,181 | (344,440) | 1,937,405 |
Improved recovery, extensions and discoveries (in BOE) |  | 146,249 | 129,926 |
Sales of minerals in place (in BOE) | (2,254,038) |  | (521,688) |
Production (sales volumes) (in BOE) | (226,819) | (208,155) | (116,437) |
Balance at the end of the period (in BOE) | 13,766,440 | 13,441,116 | 13,847,462 |
Proved developed reserves (in BOE) | 10,089,861 | 8,032,809 | 5,344,471 | 1,119,498
Increase (decrease) in proved reserves (in BOE) | 300,000 | (400,000) | 1,400,000 |
Number of reservoirs | 1 |  |  |
Proved developed reserves (as a percent) | 73.00% | 60.00% |  |
Improvement percentage of proved developed reserves | 13.00% |  |  |
Giddings Field |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Revisions of previous estimates (in BOE) |  | 369,000 |  |
Sales of minerals in place (in BOE) | (2,254,000) |  | (521,688) |
Production (sales volumes) (in BOE) | (227,000) |  |  |
Delhi Field |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Revisions of previous estimates (in BOE) | 2,806,000 | 210,000 |  |
Increase (decrease) in proved reserves (in BOE) | 2,806,000 |  |  |
Woodford properties in Oklahoma |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Revisions of previous estimates (in BOE) |  | 127,000 |  |
Giddings Field in South Texas |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Improved recovery, extensions and discoveries (in BOE) |  | 146,000 |  |
Crude Oil |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Balance at the beginning of the period (in Bbls/Mcf) | 11,638,618 | 11,567,846 | 10,254,470 |
Revisions of previous estimates (in Bbls/Mcf) | 1,826,053 | 84,219 | 1,475,918 |
Improved recovery, extensions and discoveries (in Bbls/Mcf) |  | 137,634 |  |
Sales of minerals in place (in Bbls/Mcf) | (485,536) |  | (104,577) |
Production (sales volumes) (in Bbls/Mcf) | (196,380) | (151,081) | (57,965) |
Balance at the end of the period (in Bbls/Mcf) | 12,782,755 | 11,638,618 | 11,567,846 |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Proved developed reserves (in Bbls/Mcf) | 10,077,522 | 7,670,934 | 4,986,337 | 706,053
Period of acceleration in projected reversion date of working interest resulting in upward revision of proved oil reserves | 2 years |  |  |
Working interest in proved oil reserves (as a percent) | 24.00% |  |  |
Natural Gas Liquids |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Balance at the beginning of the period (in Bbls/Mcf) | 492,473 | 712,300 | 1,036,627 |
Revisions of previous estimates (in Bbls/Mcf) | 975,515 | (212,677) | (84,154) |
Improved recovery, extensions and discoveries (in Bbls/Mcf) |  | 5,461 |  |
Sales of minerals in place (in Bbls/Mcf) | (480,832) |  | (221,469) |
Production (sales volumes) (in Bbls/Mcf) | (7,271) | (12,611) | (18,704) |
Balance at the end of the period (in Bbls/Mcf) | 979,885 | 492,473 | 712,300 |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Proved developed reserves (in Bbls/Mcf) | 8,539 | 111,978 | 100,900 | 157,302
Natural Gas |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Balance at the beginning of the period (in Bbls/Mcf) | 7,860,156 | 9,403,899 | 6,762,954 |
Revisions of previous estimates (in Bbls/Mcf) | 27,679 | (1,295,893) | 3,273,846 |
Improved recovery, extensions and discoveries (in Bbls/Mcf) |  | 18,925 | 779,556 |
Sales of minerals in place (in Bbls/Mcf) | (7,726,032) |  | (1,173,850) |
Production (sales volumes) (in Bbls/Mcf) | (139,006) | (266,775) | (238,607) |
Balance at the end of the period (in Bbls/Mcf) | 22,797 | 7,860,156 | 9,403,899 |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Proved developed reserves (in Bbls/Mcf) | 22,797 | 1,499,382 | 1,543,401 | 1,536,858

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