OIL PRICE RISK DERIVATIVES (Details Narrative) $ in Thousands	3 Months Ended
Mar. 31, 2016 USD ($) Boe	Dec. 31, 2015 USD ($)
Production of barrels of oil \| Boe	87,050
Call Contract [Member]
Derivative contracts	$ 18	$ 40
Put Contract [Member]
Derivative contracts	$ 1,079	1,674
Wells Fargo [Member]
Production of barrels of oil \| Boe	87,050
Price risk derivative	$ 1,061	$ 1,634

Fair value of each cash settlement alternative for each freestanding option contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 50
-Paragraph 5
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008

+ Details

Name:	us-gaap_OptionIndexedToIssuersEquitySettlementAlternativesCashAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of all price risk derivatives designated as fair value hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

+ Details

Name:	us-gaap_PriceRiskFairValueHedgeDerivativeAtFairValueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Energy measure of oil and natural gas production reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1204

+ Details

Name:	us-gaap_ProductionBarrelsOfOilEquivalents1
Namespace Prefix:	us-gaap_
Data Type:	num:energyItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_OptionIndexedToIssuersEquityTypeAxis=us-gaap_CallOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OptionIndexedToIssuersEquityTypeAxis=us-gaap_PutOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=useg_WellsFargoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: