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Commitments (Details) (USD $) | 0 Months Ended | 12 Months Ended |  |  | 12 Months Ended | 0 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
Nov. 02, 2012 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2012 Grizzly [Member] | Oct. 05, 2012 Grizzly [Member] | Dec. 31, 2012 Minimum [Member] | Mar. 11, 1997 WCBB [Member] wells | Dec. 31, 2012 WCBB [Member] wells | Dec. 31, 2012 Executive Officer [Member]
Commitments [Line Items] |  |  |  |  |  |  |  |  |  |
Percentage of interest in WCBB |  |  |  |  |  |  |  | 50.00% |  |
Contribution to plugging and abandonment trust |  |  |  |  |  |  |  | $ 18,000 |  |
Annual minimum wells to be plugged |  |  |  |  |  |  |  | 20 |  |
Tenure of minimum wells to be plugged, years |  |  |  |  |  |  |  | 20 years |  |
Plugging and abandonment escrow account |  | 3,113,000 | 3,121,000 |  |  |  |  |  |  |
Number of wells plugged |  |  |  |  |  |  |  |  | 354 |
Maximum annual contribution per employee (401K Plan) |  | 100.00% |  |  |  |  |  |  |  |
Miminum matching employer contribution for 401k |  |  |  |  |  |  | 3.00% |  |  |
Cost recognized on defined contribution plan |  | 361,000 | 310,000 | 316,000 |  |  |  |  |  |
Employement agreement | 3 years |  |  |  |  |  |  |  |  |
Extension period | 1 year |  |  |  |  |  |  |  |  |
Notice period | 90 days |  |  |  |  |  |  |  |  |
Other Commitment |  |  |  |  |  |  |  |  |  | 7,050,000
Contractual obligation for future salaries and benefits |  |  |  |  | 6,300,000 | 8,500,000 |  |  |  |
Contractual oblication in excess of |  | $ 2,000,000 |  |  |  |  |  |  |  |

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