Line of credit facility extended date.

No definition available.

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Namespace Prefix:	psn_
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Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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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
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-Publisher FASB
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-Topic 210
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Topic 942
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-Section S99
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-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Balance Type:	na
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

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

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ 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
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
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-Publisher FASB
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-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility first became available, in CCYY-MM-DD format.

+ References

+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
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

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of notes payable.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

+ Details

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Balance Type:	credit
Period Type:	duration

- Details

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- Details

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Debt and Credit Facilities - Additional Information (Details) - USD ($)			3 Months Ended
	May 10, 2019	Jul. 01, 2014	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Jan. 31, 2019
Debt Instrument [Line Items]
Debt issuance costs incurred			$ 500,000
Letters of credit outstanding amount			193,500,000			$ 197,300,000
Term Loan
Debt Instrument [Line Items]
Interest expense				$ 1,400,000
Repayment of outstanding balance	$ 150,000,000.0
Debt Amount							$ 150,000,000.0
Term Loan \| Forecast
Debt Instrument [Line Items]
Debt instrument, outstanding amount					$ 0
Level 2
Debt Instrument [Line Items]
Senior notes, fair value			263,900,000
Accrued Expenses and Other Current Liabilities
Debt Instrument [Line Items]
Interest payable			2,600,000			5,700,000
Senior Notes
Debt Instrument [Line Items]
Interest expense			3,100,000	3,100,000
Interest payments			6,200,000	6,200,000
Debt instrument, outstanding amount			250,000,000			250,000,000
Private Placement
Debt Instrument [Line Items]
Debt issuance costs incurred			$ 1,100,000
Repayment of outstanding balance		$ 250,000,000.0
Credit Agreement
Debt Instrument [Line Items]
Amended and restated credit agreement date			Nov. 30, 2017
Debt issuance costs incurred			$ 2,000,000.0
Revolving credit facility			500,000,000
Increase in revolving credit facility			$ 550,000,000
Credit agreement extended date			Nov. 30, 2022
Letters of credit outstanding amount			$ 44,900,000			$ 43,700,000
Interest expense			$ 300,000	$ 3,400,000
Credit Agreement \| Minimum
Debt Instrument [Line Items]
Interest rate			1.90%
Credit Agreement \| Maximum
Debt Instrument [Line Items]
Interest rate						3.02%
Credit Agreement \| Base Rate \| Minimum
Debt Instrument [Line Items]
Margin interest rate			0.125%
Credit Agreement \| Base Rate \| Maximum
Debt Instrument [Line Items]
Margin interest rate			1.00%
Credit Agreement \| LIBOR \| Minimum
Debt Instrument [Line Items]
Margin interest rate			1.125%
Credit Agreement \| LIBOR \| Maximum
Debt Instrument [Line Items]
Margin interest rate			2.00%