Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Fixed Charge Coverage Ratio

+ References

No definition available.

+ Details

Name:	pdm_DebtInstrumentFixedChargeCoverageRatio
Namespace Prefix:	pdm_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Maximum Leverage Ratio

+ References

No definition available.

+ Details

Name:	pdm_DebtInstrumentMaximumLeverageRatio
Namespace Prefix:	pdm_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Maximum Secured Debt Ratio

+ References

No definition available.

+ Details

Name:	pdm_DebtInstrumentMaximumSecuredDebtRatio
Namespace Prefix:	pdm_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Unencumbered Interest Coverage Ratio

+ References

No definition available.

+ Details

Name:	pdm_DebtInstrumentUnencumberedInterestCoverageRatio
Namespace Prefix:	pdm_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Unencumbered Leverage Ratio

+ References

No definition available.

+ Details

Name:	pdm_DebtInstrumentUnencumberedLeverageRatio
Namespace Prefix:	pdm_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Maturity Extension Period

+ References

No definition available.

+ Details

Name:	pdm_LineOfCreditFacilityMaturityExtensionPeriod
Namespace Prefix:	pdm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Maximum Borrowing Capacity, After Optional Increase

+ References

No definition available.

+ Details

Name:	pdm_LineOfCreditFacilityMaximumBorrowingCapacityAfterOptionalIncrease
Namespace Prefix:	pdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line Of Credit Facility, Maximum Maturity Extension Period

+ References

No definition available.

+ Details

Name:	pdm_LineOfCreditFacilityMaximumMaturityExtensionPeriod
Namespace Prefix:	pdm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Number of Maturity Extension Periods

+ References

No definition available.

+ Details

Name:	pdm_LineOfCreditFacilityNumberofMaturityExtensionPeriods
Namespace Prefix:	pdm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Optional Increase To Maximum Borrowing Capacity

+ References

No definition available.

+ Details

Name:	pdm_LineOfCreditFacilityOptionalIncreaseToMaximumBorrowingCapacity
Namespace Prefix:	pdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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

- Definition

Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

+ Details

Name:	us-gaap_InterestPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Number of interest rate derivative instruments held by the entity at the reporting date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

+ Details

Name:	us-gaap_NumberOfInterestRateDerivativesHeld
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=pdm_Unsecured300million2013TermLoanMaturing2019Member
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_DebtInstrumentAxis=pdm_Unsecured170Million2015TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pdm_Unsecured500Million2015LineofCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pdm_Unsecured500Million2018LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=pdm_A300Million2011UnsecuredTermLoanMaturing2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pdm_A250Million2018UnsecuredTermLoanMaturing2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=pdm_Unsecured2018500MillionLineOfCredit2011300MillionTermLoanAnd2018250MillionTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	pdm_DebtCovenantPeriodAxis=pdm_ThroughMarch292020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt (Narrative) (Details)	1 Months Ended	12 Months Ended
Debt (Narrative) (Details)	Jan. 31, 2018 USD ($)	Dec. 31, 2018 USD ($) contract period	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Weighted average interest rate		3.76%	3.48%
Interest paid		$ 63,100,000	$ 67,600,000	$ 69,000,000.0
Unsecured (Variable and Fixed)
Debt Instrument [Line Items]
Derivative, notional amount		$ 450,000,000
Weighted average interest rate		3.75%
$300 Million Unsecured 2013 Term Loan \| Unsecured (Variable and Fixed)
Debt Instrument [Line Items]
Repayments of debt	$ 300,000,000	$ 300,000,000
Face amount of facility		$ 300,000,000
$300 Million Unsecured 2013 Term Loan \| Unsecured (Variable and Fixed) \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.20%
$170 Million Unsecured 2015 Term Loan \| Unsecured (Variable and Fixed)
Debt Instrument [Line Items]
Repayments of debt		$ 170,000,000
Face amount of facility		$ 170,000,000
$170 Million Unsecured 2015 Term Loan \| Unsecured (Variable and Fixed) \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.125%
$500 Million Unsecured 2015 Line of Credit \| Unsecured (Variable and Fixed) \| Line of Credit
Debt Instrument [Line Items]
Amount of line of credit		$ 500,000,000
Face amount of facility		$ 500,000,000
$500 Million Unsecured 2015 Line of Credit \| Unsecured (Variable and Fixed) \| Line of Credit \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.00%
Unsecured 500 Million 2018 Line Of Credit \| Unsecured (Variable and Fixed)
Debt Instrument [Line Items]
Face amount of facility		$ 500,000,000
Unsecured 500 Million 2018 Line Of Credit \| Unsecured (Variable and Fixed) \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		0.90%
Unsecured 500 Million 2018 Line Of Credit \| Unsecured (Variable and Fixed) \| Line of Credit
Debt Instrument [Line Items]
Amount of line of credit		$ 500,000,000
Debt instrument term		4 years
Number of extension periods \| period		2
Maturity extension period		6 months
Optional increase to maximum borrowing capacity		$ 500,000,000
Maximum borrowing capacity, after optional increase		$ 1,000,000,000.0
Additional extension period		1 year
Unsecured 500 Million 2018 Line Of Credit \| Unsecured (Variable and Fixed) \| Line of Credit \| Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Basis spread on variable interest rate		0.50%
Unsecured 500 Million 2018 Line Of Credit \| Unsecured (Variable and Fixed) \| Line of Credit \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		0.90%
Amended and Restated $300 Million Unsecured 2011 Term Loan \| Unsecured (Variable and Fixed)
Debt Instrument [Line Items]
Face amount of facility		$ 300,000,000
Additional extension period		22 months
Amended and Restated $300 Million Unsecured 2011 Term Loan \| Unsecured (Variable and Fixed) \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.00%
Amended and Restated $300 Million Unsecured 2011 Term Loan \| Unsecured (Variable and Fixed) \| Line of Credit \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.00%
$250 Million Unsecured 2018 Term Loan \| Interest rate swaps
Debt Instrument [Line Items]
Number of swap agreements \| contract		3
Derivative, notional amount		$ 150,000,000
$250 Million Unsecured 2018 Term Loan \| Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Basis spread on variable interest rate		0.50%
$250 Million Unsecured 2018 Term Loan \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.00%
$250 Million Unsecured 2018 Term Loan \| Unsecured (Variable and Fixed)
Debt Instrument [Line Items]
Debt instrument term		7 years
Face amount of facility		$ 250,000,000
Derivative, notional amount		$ 150,000,000
$250 Million Unsecured 2018 Term Loan \| Unsecured (Variable and Fixed) \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.60%
Unsecured, 2018 $500 Million Line Of Credit, 2011 $300 Million Term Loan And 2018 $250 Million Term Loan \| Unsecured (Variable and Fixed)
Debt Instrument [Line Items]
Unencumbered interest coverage ratio		1.75
Unencumbered leverage ratio		1.60
Fixed charge coverage ratio		1.50
Maximum leverage ratio		0.60
Maximum secured debt ratio		0.40
Minimum \| Unsecured 500 Million 2018 Line Of Credit \| Unsecured (Variable and Fixed) \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable interest rate		0.775%
Minimum \| Amended and Restated $300 Million Unsecured 2011 Term Loan \| Unsecured (Variable and Fixed) \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable interest rate		0.85%	0.90%
Minimum \| $250 Million Unsecured 2018 Term Loan \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.45%
Maximum \| Unsecured 500 Million 2018 Line Of Credit \| Unsecured (Variable and Fixed) \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.45%
Maximum \| Amended and Restated $300 Million Unsecured 2011 Term Loan \| Unsecured (Variable and Fixed) \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.65%	1.90%
Maximum \| $250 Million Unsecured 2018 Term Loan \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable interest rate		2.40%
Through March 29, 2020 \| $250 Million Unsecured 2018 Term Loan \| Unsecured (Variable and Fixed)
Debt Instrument [Line Items]
Derivative fixed interest rate		4.11%