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SHAREHOLDERS' EQUITY, Options Outstanding and Exercisable and Weighted Average Fair Value Assumptions Used (Details) (Details) (USD $) | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Fair Value Assumptions [Abstract] |  |  |
Risk free interest rate (in hundredths) | 2.06%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate | 1.66%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate |
Expected lives | 6 years | 6 years |
Expected volatility (in hundredths) | 65.45%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate | 62.59%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate |
Expected dividend yield (in hundredths) | 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate | 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate | 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
Minimum [Member] |  |  |
Fair Value Assumptions [Abstract] |  |  |
Risk free interest rate, minimum (in hundredths) |  |  | 0.82%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum / us-gaap_RangeAxis = us-gaap_MinimumMember
Expected lives |  |  | 5 years
Expected volatility, minimum (in hundredths) |  |  | 61.87%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum / us-gaap_RangeAxis = us-gaap_MinimumMember
Maximum [Member] |  |  |
Fair Value Assumptions [Abstract] |  |  |
Risk free interest rate, maximum (in hundredths) |  |  | 1.41%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum / us-gaap_RangeAxis = us-gaap_MaximumMember
Expected lives |  |  | 6 years
Expected volatility, maximum (in hundredths) |  |  | 63.59%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum / us-gaap_RangeAxis = us-gaap_MaximumMember
Employee Stock Options [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Outstanding at end of period (in shares) | 2,097,413 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember |  |
Weighted average remaining contractual life | 3 years 7 months 24 days |  |
Weighted average exercise price (in dollars per share) | 3.82 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember |  |
Exercisable at end of period (in shares) | 1,949,080 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember |  |
Weighted average exercise price (in dollars per share) | 3.95 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember |  |
Employee Stock Options [Member] | $2.08 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range upper range limit (in dollars per share) | 2.08 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Outstanding at end of period (in shares) | 270,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Weighted average remaining contractual life | 8 years 8 months 26 days |  |
Weighted average exercise price (in dollars per share) | 2.08 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Exercisable at end of period (in shares) | 166,668 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Weighted average exercise price (in dollars per share) | 2.08 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Employee Stock Options [Member] | $2.09 - $2.32 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 2.09 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Exercise price range upper range limit (in dollars per share) | 2.32 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Outstanding at end of period (in shares) | 123,333 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Weighted average remaining contractual life | 7 years 6 months 11 days |  |
Weighted average exercise price (in dollars per share) | 2.32 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Exercisable at end of period (in shares) | 78,332 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Weighted average exercise price (in dollars per share) | 2.32 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Employee Stock Options [Member] | $2.33 - $2.52 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 2.33 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Exercise price range upper range limit (in dollars per share) | 2.52 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Outstanding at end of period (in shares) | 405,312 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Weighted average remaining contractual life | 3 years 8 months 23 days |  |
Weighted average exercise price (in dollars per share) | 2.52 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Exercisable at end of period (in shares) | 405,312 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Weighted average exercise price (in dollars per share) | 2.52 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Employee Stock Options [Member] | $2.53 - $3.86 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 2.53 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range4Member |  |
Exercise price range upper range limit (in dollars per share) | 3.86 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range4Member |  |
Outstanding at end of period (in shares) | 273,768 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range4Member |  |
Weighted average remaining contractual life | 0 years 9 months 14 days |  |
Weighted average exercise price (in dollars per share) | 3.86 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range4Member |  |
Exercisable at end of period (in shares) | 273,768 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range4Member |  |
Weighted average exercise price (in dollars per share) | 3.86 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range4Member |  |
Employee Stock Options [Member] | $3.87 - $4.97 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 3.87 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range5Member |  |
Exercise price range upper range limit (in dollars per share) | 4.97 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range5Member |  |
Outstanding at end of period (in shares) | 1,025,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range5Member |  |
Weighted average remaining contractual life | 2 years 6 months 25 days |  |
Weighted average exercise price (in dollars per share) | 4.97 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range5Member |  |
Exercisable at end of period (in shares) | 1,025,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range5Member |  |
Weighted average exercise price (in dollars per share) | 4.97 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = us-gaap_EmployeeStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range5Member |  |
Director Stock Options [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Outstanding at end of period (in shares) | 178,666 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember |  |
Weighted average remaining contractual life | 7 years 10 months 17 days |  |
Weighted average exercise price (in dollars per share) | 3.28 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember |  |
Exercisable at end of period (in shares) | 82,333 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember |  |
Weighted average exercise price (in dollars per share) | 3.30 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember |  |
Director Stock Options [Member] | $2.08 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range upper range limit (in dollars per share) | 2.08 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Outstanding at end of period (in shares) | 27,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Weighted average remaining contractual life | 8 years 6 months |  |
Weighted average exercise price (in dollars per share) | 2.08 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Exercisable at end of period (in shares) | 9,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Weighted average exercise price (in dollars per share) | 2.08 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range10Member |  |
Director Stock Options [Member] | $2.09 - $2.32 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 2.09 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Exercise price range upper range limit (in dollars per share) | 2.32 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Outstanding at end of period (in shares) | 6,666 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Weighted average remaining contractual life | 7 years 6 months 11 days |  |
Weighted average exercise price (in dollars per share) | 2.32 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Exercisable at end of period (in shares) | 3,333 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Weighted average exercise price (in dollars per share) | 2.32 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range11Member |  |
Director Stock Options [Member] | $2.33 - $2.52 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 2.33 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Exercise price range upper range limit (in dollars per share) | 2.52 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Outstanding at end of period (in shares) | 10,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Weighted average remaining contractual life | 3 years 8 months 23 days |  |
Weighted average exercise price (in dollars per share) | 2.52 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Exercisable at end of period (in shares) | 10,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Weighted average exercise price (in dollars per share) | 2.52 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range2Member |  |
Director Stock Options [Member] | $2.53 - $2.85 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 2.53 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range8Member |  |
Exercise price range upper range limit (in dollars per share) | 2.85 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range8Member |  |
Outstanding at end of period (in shares) | 45,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range8Member |  |
Weighted average remaining contractual life | 7 years 2 months 23 days |  |
Weighted average exercise price (in dollars per share) | 2.85 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range8Member |  |
Exercisable at end of period (in shares) | 30,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range8Member |  |
Weighted average exercise price (in dollars per share) | 2.85 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range8Member |  |
Director Stock Options [Member] | $2.86 - $4.19 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 2.86 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range9Member |  |
Exercise price range upper range limit (in dollars per share) | 4.19 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range9Member |  |
Outstanding at end of period (in shares) | 80,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range9Member |  |
Weighted average remaining contractual life | 8 years 10 months 24 days |  |
Weighted average exercise price (in dollars per share) | 3.88 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range9Member |  |
Exercisable at end of period (in shares) | 20,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range9Member |  |
Weighted average exercise price (in dollars per share) | 4.19 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range9Member |  |
Director Stock Options [Member] | $4.20 - $5.04 [Member] |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |
Exercise price range lower range limit (in dollars per share) | 4.20 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range6Member |  |
Exercise price range upper range limit (in dollars per share) | 5.04 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range6Member |  |
Outstanding at end of period (in shares) | 10,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range6Member |  |
Weighted average remaining contractual life | 5 years 5 months 23 days |  |
Weighted average exercise price (in dollars per share) | 5.04 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range6Member |  |
Exercisable at end of period (in shares) | 10,000 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range6Member |  |
Weighted average exercise price (in dollars per share) | 5.04 us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1 / us-gaap_PlanNameAxis = useg_DirectorStockOptionMember / us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis = useg_Range6Member |  |

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- Definition The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 14.D.2) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section D -Subsection 2 + Details
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. + References No definition available. + Details
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- Definition The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. + References No definition available. + Details
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iv) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The maximum risk-free interest rate assumption that is used in valuing an option on its own shares. + References No definition available. + Details
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- Definition The minimum risk-free interest rate assumption that is used in valuing an option on its own shares. + References No definition available. + Details
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- Definition Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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