Disclosure About Oil and Gas Producing Activities (Unaudited) (Details 6) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Proven Properties [Abstract]
Acquisition, equipment, exploration, drilling and evnironmental costs	$ 9,731,407	$ 7,817,374
Less: Accumulated depletion, depreciation and amortization	(6,094,764)	(5,808,836)
Proved	3,636,643	2,008,538
Unproven Properties:
Oil Gas Properties Using Full Cost Method Accounting Unproved	242,294	413,073
Net capitalized costs - oil and gas properties	$ 3,878,937	$ 2,421,611

Net amount of capitalized costs relating to oil and gas producing activates.

No definition available.

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

- Definition

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

+ References

No definition available.

+ Details

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

- Details

Name:	upl_ProvenPropertiesAbstract
Namespace Prefix:	upl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accumulated depreciation, depletion, amortization and valuation allowance relating to oil and gas producing activities.

+ References

+ Details

Name:	us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Definition

Net amount of capitalized costs relating to oil and gas producing activities.

+ References

+ Details

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

- Definition

Capitalized costs of proved properties incurred for any combination mineral interests acquisitions; wells and related equipment; support equipment and facilities; and uncompleted wells and equipment and other costs not previously disclosed within this table.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 360

-Glossary Proved Properties

-URI http://asc.fasb.org/extlink&oid=6522428

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Properties

-URI http://asc.fasb.org/extlink&oid=21914647

+ Details

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