Amortization percent of term loan quarterly basis.

No definition available.

Name:	upl_AmortizationPercentOfTermLoanQuarterlyBasis
Namespace Prefix:	upl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Bottom point of asset coverage ratio to trigger mandatory prepayment.

+ References

No definition available.

+ Details

Name:	upl_BottomPointOfAssetCoverageRatioToTriggerMandatoryPrepayment
Namespace Prefix:	upl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument call protection percentage.

+ References

No definition available.

+ Details

Name:	upl_DebtInstrumentCallProtectionPercentage
Namespace Prefix:	upl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument discount percentage on principal amount.

+ References

No definition available.

+ Details

Name:	upl_DebtInstrumentDiscountPercentageOnPrincipalAmount
Namespace Prefix:	upl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of collateral coverage.

+ References

No definition available.

+ Details

Name:	upl_PercentageOfCollateralCoverage
Namespace Prefix:	upl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

States whether the entity was in compliance with the debt covenants throughout the reporting period, and describes facts and circumstances of any compliance failure.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_SubsidiaryIssuerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=upl_BarclaysBankPlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=upl_TermLoanSecuredDueTwoThousandTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=upl_ExchangeAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=upl_CashNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_PaymentInKindPIKNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long Term Debt - Ultra Resources, Inc. - Term Loan - Additional Information (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended
	Apr. 30, 2017	Dec. 31, 2018	Mar. 31, 2019
Debt Instrument [Line Items]
Principal repayment obligation		$ 2,044,035	$ 1,963,656
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024
Debt Instrument [Line Items]
Debt, original issue discount as percentage on principal	1.00%
Principal repayment obligation			$ 975,100
Amortization of term loan, quarterly basis			0.25%
Maturity date			Apr. 12, 2024
Mandatory prepayment trigger, on asset coverage ratio			200.00%
Debt instrument, covenant compliance			At March 31, 2019, Ultra Resources was in compliance with all of its debt covenants under the Term Loan Agreement.
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024 \| LIBOR
Debt Instrument [Line Items]
Variable rate			4.00%
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024 \| Base Rate
Debt Instrument [Line Items]
Variable rate			3.00%
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024 \| Exchange Agreement
Debt Instrument [Line Items]
Variable rate		1.00%
Percentage of collateral coverage	85.00%	95.00%
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024 \| Exchange Agreement \| Until December 21, 2019
Debt Instrument [Line Items]
Debt instrument call protection percentage		102.00%
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024 \| Exchange Agreement \| Until December 21, 2020
Debt Instrument [Line Items]
Debt instrument call protection percentage		101.00%
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024 \| Cash Notes \| Exchange Agreement
Debt Instrument [Line Items]
Variable rate		0.75%
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024 \| Payment in Kind (PIK) Note \| Base Rate
Debt Instrument [Line Items]
Variable rate			0.25%
Ultra Resources, Inc. \| Barclays Bank PLC \| Term Loan Secured Due 2024 \| Payment in Kind (PIK) Note \| Exchange Agreement
Debt Instrument [Line Items]
Variable rate		0.25%