Amount of debt hedged by interest rate derivatives.

No definition available.

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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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Period Type:	instant

- Definition

Term Loan, Quarterly Principal Payment Percentage

+ References

No definition available.

+ Details

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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

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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/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

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

- Definition

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

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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, after accumulated amortization, of debt issuance costs classified as noncurrent. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-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:	debit
Period Type:	instant

- 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

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- 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

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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

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-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

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

- Details

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- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=prxl_A2016CreditAgreementMember
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Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Period Type:

- Details

Name:	us-gaap_VariableRateAxis=prxl_OneMonthLIBORPlusRateMember
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- Details

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

- Details

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Balance Type:
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- Details

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- Details

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Credit Agreements 2014 Credit Agreement (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	May 31, 2013	Mar. 31, 2017	Mar. 11, 2016	Oct. 01, 2015	Sep. 30, 2015	Jun. 12, 2015	Oct. 15, 2014	Jul. 25, 2013
Debt Instrument [Line Items]
Derivative, Fixed Interest Rate	0.73%			1.104%
Long-term Debt, Gross		$ 702.8				$ 7.1
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity		140.0
Senior Notes due in 2020 [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Noncurrent, Net					$ 0.3
2016 Credit Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 210.0
Credit facility, maximum borrowing capacity							$ 750.0
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.25%
2016 Credit Agreement [Member] \| LIBOR Plus Margin [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.00%
2016 Credit Agreement [Member] \| Federal Funds Plus Margin [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.50%
2016 Credit Agreement [Member] \| One Month LIBOR Plus Rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.00%
2016 Credit Agreement [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 390.0	$ 0.0
2016 Credit Agreement [Member] \| Term Loan [Member] \| Debt Instrument, Redemption, Period One [Member]
Debt Instrument [Line Items]
Term Loan, Quarterly Principal Payment Percentage			0.63%
2016 Credit Agreement [Member] \| Term Loan [Member] \| Debt Instrument, Redemption, Period Two [Member]
Debt Instrument [Line Items]
Term Loan, Quarterly Principal Payment Percentage			1.25%
2016 Credit Agreement [Member] \| Term Loan [Member] \| Debt Instrument, Redemption, Period Three [Member]
Debt Instrument [Line Items]
Term Loan, Quarterly Principal Payment Percentage			1.88%
2016 Credit Agreement [Member] \| Term Loan [Member] \| Debt Instrument, Redemption, Period Four [Member]
Debt Instrument [Line Items]
Term Loan, Quarterly Principal Payment Percentage			2.50%
2016 Credit Agreement [Member] \| Swingline Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity			$ 0.0
2016 Credit Agreement [Member] \| Revolving Credit Facility [Member]
Debt Instrument [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
2014 Credit Agreement [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							500.0
2014 Credit Agreement [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt							200.0
2014 Credit Agreement [Member] \| Swingline Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity							100.0
2014 Credit Agreement [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity							300.0
Letters of Credit, maximum issuance amount							$ 10.0
Senior Notes due in 2020 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross					$ 100.0
Debt Instrument, Interest Rate, Stated Percentage								3.11%
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Amount Of Debt Hedged By Interest Rate Derivatives	$ 100.0