Derivatives - Fair Value of Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate Notional Value	$ 794.4
Aggregate Fair Value	$ (27.7)	$ (8.5)
Weighted Average Interest Rate	2.13%
Interest Rate Swaps 2020 Maturity
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate Fair Value		0.2
Interest Rate Swaps 2021 Maturity
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate Notional Value	$ 494.4
Aggregate Fair Value	$ (8.1)	(1.4)
Weighted Average Interest Rate	1.79%
Interest Rate Swaps 2023 Maturity
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate Notional Value	$ 300.0
Aggregate Fair Value	$ (19.6)	$ (7.3)
Weighted Average Interest Rate	2.70%

Average fixed interest rate related to the group of interest rate derivatives.

No definition available.

Name:	us-gaap_DerivativeAverageFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

+ Details

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

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

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=pei_InterestRateSwaps2020MaturityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=pei_InterestRateSwaps2021MaturityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=pei_InterestRateSwaps2023MaturityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: