Name:	upl_CapitalizedExplorationCosts
Namespace Prefix:	upl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

Name:	upl_ChangeOfOilGasPropertiesUsingFullCostMethodAccountingUnproved
Namespace Prefix:	upl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Total amount of interest that was capitalized during the period on unproven oil and gas properties.

No definition available.

Name:	upl_InterestCostsCapitalizedInception
Namespace Prefix:	upl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Interest capitalized on unproven oil and gas properties during the year.

No definition available.

Name:	upl_InterestCostsCapitalizedYear
Namespace Prefix:	upl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Properties on which oil or natural gas reserves do not exist with enough certainty to be classified as proved.

No definition available.

Name:	upl_OilGasPropertiesUsingFullCostMethodAccountingUnproved
Namespace Prefix:	upl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The capitalized costs incurred during the period (excluded from amortization) to purchase, lease or otherwise acquire an unproved property, including costs of lease bonuses and options to purchase or lease properties, the portion of costs applicable to minerals when land including mineral rights is purchased in fee, brokers' fees, recording fees, legal costs, and other costs incurred in acquiring properties.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-10.(c)(7)(ii))
-URI http://asc.fasb.org/extlink&oid=27015464&loc=d3e511914-122862

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 10
-Paragraph c
-Subparagraph 3(ii)(A)
-Article 4

Name:	us-gaap_AcquisitionCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The capitalized costs incurred (excluded from amortization), as of the date of the balance sheet, to purchase, lease or otherwise acquire an unproved property, including costs of lease bonuses and options to purchase or lease properties, the portion of costs applicable to minerals when land including mineral rights is purchased in fee, brokers' fees, recording fees, legal costs, and other costs incurred in acquiring properties.

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

- References

No definition available.

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The capitalized costs incurred during the period (excluded from amortization) in identifying areas that may warrant examination and in examining specific areas that are considered to have prospects of containing oil and gas reserves, including costs of drilling exploratory wells and exploratory-type stratigraphic test wells. Exploration costs may be incurred both before acquiring the related property (sometimes referred to in part as prospecting costs) and after acquiring the property. Principal types of exploration costs, which include depreciation and applicable operating costs of support equipment and facilities and other costs of exploration activities, are: costs of topographical, geographical and geophysical studies, rights of access to properties to conduct those studies, and salaries and other expenses of geologists, geophysical crews, and others conducting those studies. Collectively, these are sometimes referred to as geological and geophysical or "G&G" costs. Exploration costs also include costs of carrying and retaining undeveloped properties, such as delay rentals, ad valorem taxes on properties, legal costs for title defense, the maintenance of land and lease records, dry hole contributions and bottom hole contributions, costs of drilling and equipping exploratory wells and costs of drilling exploratory-type stratigraphic test wells.