Name:	upl_DebtInstrumentInterestRateTermsLibor
Namespace Prefix:	upl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Description of the interest rate as being variable and identification of the Prime index as the rate on which the interest is based and the number of points or percentage added to that index or rate to set the rate.

No definition available.

Name:	upl_DebtInstrumentInterestRateTermsPrime
Namespace Prefix:	upl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

The total amount available to be issued as letters of credit under the Company's bank credit facility.

No definition available.

Name:	upl_LettersOfCreditAvailability
Namespace Prefix:	upl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Maximum aggregate commitment available under the current revolving credit facility.

No definition available.

Name:	upl_MaxRevolvingBankLoanComitmentValue
Namespace Prefix:	upl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Initial loan commitment for revolving credit facility.

No definition available.

Name:	upl_RevolvingBankLoanComitmentValue
Namespace Prefix:	upl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Subparagraph b

-Article 5

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

Including the current and noncurrent portions, the carrying value as of the balance sheet date of notes payable to banks, excluding mortgage notes, initially due beyond one year or beyond the operating cycle if longer.

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

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

-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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5