Line of Credit (Details) - Revolving Credit Facility [Member] $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($) LetterOfCredit
Credit Agreement [Member]
Line of Credit [Abstract]
Maximum borrowing capacity	$ 75.0
Additional commitment increase	25.0
Allowable amount of letters of credit for issuance	$ 10.0
Number of letters of credit outstanding \| LetterOfCredit	0
Line of credit facility, maximum borrowing capacity, available	$ 93.0
Annual commitment fee percentage on unused capacity	0.20%
Ratio of EBITDA plus stock compensation and minus income taxes paid and capital expenditures to interest expense and scheduled payments due for borrowings	2.00
Ratio of current maturities of long-term debt to EBITDA plus stock compensation and minus income taxes paid and capital expenditures	2.75
Credit Agreement [Member] \| Prime Rate [Member]
Line of Credit [Abstract]
Interest rate at period end	3.75%
Credit Agreement [Member] \| Prime Rate [Member] \| Minimum [Member]
Line of Credit [Abstract]
Margin interest rate percentage	0.00%
Credit Agreement [Member] \| Prime Rate [Member] \| Maximum [Member]
Line of Credit [Abstract]
Margin interest rate percentage	0.50%
Credit Agreement [Member] \| LIBOR [Member]
Line of Credit [Abstract]
Debt Instrument, Term of variable rate	1 month
Interest rate at period end	0.772%
Term of variable rate	1 month
First Amendment [Member]
Line of Credit [Abstract]
Maximum borrowing capacity	$ 90.0
Maximum borrowing capacity increase	15.0
Second Amendment [Member]
Line of Credit [Abstract]
Maximum borrowing capacity	125.0
Additional commitment increase	50.0
Maximum borrowing capacity increase	$ 35.0
Maturity date	Jul. 31, 2017
Fourth Amendment [Member]
Line of Credit [Abstract]
Maturity date	Jul. 31, 2018
Fourth Amendment [Member] \| LIBOR [Member]
Line of Credit [Abstract]
Decrease in margin interest rate percentage	0.25%
Fourth Amendment [Member] \| LIBOR [Member] \| Minimum [Member]
Line of Credit [Abstract]
Margin interest rate percentage	1.75%
Fourth Amendment [Member] \| LIBOR [Member] \| Maximum [Member]
Line of Credit [Abstract]
Margin interest rate percentage	2.25%

Decrease in percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	prft_DebtInstrumentBasisSpreadOnVariableRate1Decrease
Namespace Prefix:	prft_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of additional commitment increase on the credit facility.

+ References

No definition available.

+ Details

Name:	prft_LineOfCreditFacilityAdditionalCommitmentIncrease
Namespace Prefix:	prft_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Allowable amount for issuance of letters of credit under the credit facility.

+ References

No definition available.

+ Details

Name:	prft_LineOfCreditFacilityAllowableAmountForIssuanceOfLettersOfCredit
Namespace Prefix:	prft_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Increase for additional borrowings on the credit facility during the period.

+ References

No definition available.

+ Details

Name:	prft_LineOfCreditFacilityMaximumBorrowingCapacityIncrease
Namespace Prefix:	prft_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of letters of credit outstanding under the credit facility.

+ References

No definition available.

+ Details

Name:	prft_LineOfCreditFacilityNumberOfLettersOfCreditOutstanding
Namespace Prefix:	prft_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of current maturities of long-term debt to EBITDA plus stock compensation and minus income taxes paid and capital expenditures.

+ References

No definition available.

+ Details

Name:	prft_RatioOfCurrentMaturitiesOfLongTermDebtToEBITDAPlusStockCompensationAndMinusIncomeTaxesPaidAndCapitalExpenditures
Namespace Prefix:	prft_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Ratio of EBITDA plus stock compensation and minus income taxes paid and capital expenditures to interest expense and scheduled payments due for borrowings.

+ References

No definition available.

+ Details

Name:	prft_RatioOfEBITDAPlusStockCompensationAndMinusIncomeTaxesPaidAndCapitalExpendituresToInterestExpenseAndScheduledPaymentsDueForBorrowings
Namespace Prefix:	prft_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of the interest rate that fluctuates over time as a result of an underlying benchmark interest rate or index.

+ References

No definition available.

+ Details

Name:	prft_snr_DebtInstrumentTermOfVariableRate
Namespace Prefix:	prft_
Data Type:	xbrli:durationItemType
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

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ 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(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

The effective interest rate at the end of the reporting period.

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(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

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

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
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

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
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=prft_FirstAmendmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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