Amount of debt hedged by interest rate derivatives.

No definition available.

Name:	prxl_AmountOfDebtHedgedByInterestRateDerivatives
Namespace Prefix:	prxl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Credit facility, maximum borrowing capacity under term loan and revolver combined

+ References

No definition available.

+ Details

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

- Definition

The total amount of the contingent obligations allowed to issue under letters of credit as of the reporting date

+ References

No definition available.

+ Details

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

- Definition

Term Loan, Quarterly Principal Payment Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	prxl_
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

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

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

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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

Reference 2: 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 3: 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

+ Details

Name:	us-gaap_LineOfCredit
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

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
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

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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(a)(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 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_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=prxl_A2016CreditAgreementMember
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Data Type:	na
Balance Type:
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- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prxl_TermLoanMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prxl_SwinglineLoanMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=prxl_LIBORPlusMarginMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=prxl_OneMonthLIBORPlusRateMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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Data Type:	na
Balance Type:
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- Details

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- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
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- Details

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Credit Agreements 2016 Credit Agreement (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended
	Mar. 11, 2016	May 31, 2013	Sep. 30, 2016	Dec. 31, 2016	Oct. 01, 2015	Oct. 15, 2014	Sep. 30, 2011
Line of Credit Facility [Line Items]
Derivative, Fixed Interest Rate		0.73%			1.104%
2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Term	5 years
Long-term Debt				$ 285.0
Credit facility, maximum borrowing capacity						$ 750.0
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage			0.25%
Revolving Credit Facility [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Long-term Line of Credit	$ 0.0
Line of Credit Facility, Current Borrowing Capacity	0.0
Letters of Credit, maximum issuance amount	10.0
Term Loan [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Long-term Debt	0.0			$ 392.5
Swingline Loan [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 0.0
LIBOR Plus Margin [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate			2.00%
One Month LIBOR Plus Rate [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate			1.00%
Debt Instrument, Redemption, Period One [Member] \| Term Loan [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Term Loan, Quarterly Principal Payment Percentage	0.63%
Debt Instrument, Redemption, Period Two [Member] \| Term Loan [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Term Loan, Quarterly Principal Payment Percentage	1.25%
Debt Instrument, Redemption, Period Three [Member] \| Term Loan [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Term Loan, Quarterly Principal Payment Percentage	1.88%
Debt Instrument, Redemption, Period Four [Member] \| Term Loan [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Term Loan, Quarterly Principal Payment Percentage	2.50%
Debt Instrument, Redemption, Period Five [Member] \| Term Loan [Member] \| 2016 Credit Agreement [Member]
Line of Credit Facility [Line Items]
Term Loan, Quarterly Principal Payment Percentage	72.50%
Interest Rate Swap [Member]
Line of Credit Facility [Line Items]
Amount Of Debt Hedged By Interest Rate Derivatives		$ 100.0	$ 100.0
Derivative, Fixed Interest Rate							1.30%