v3.8.0.1

Segment Information - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017 States Aircraft Location Segment	Sep. 30, 2016
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			3
National Science Foundation [Member]
Segment Reporting Information [Line Items]
Number of aircraft assigned			6
Hospitals Contracts [Member]
Segment Reporting Information [Line Items]
Segment revenue	15.00%	27.00%	17.00%	29.00%
Fixed Term Customer Contract [Member]
Segment Reporting Information [Line Items]
Segment revenue	89.00%	92.00%	90.00%	92.00%
Contracted Customers [Member]
Segment Reporting Information [Line Items]
Segment revenue			10.00%	8.00%
Minimum [Member]
Segment Reporting Information [Line Items]
Term of contract			1 year
Maximum [Member]
Segment Reporting Information [Line Items]
Term of contract			7 years
Oil and Gas [Member]
Segment Reporting Information [Line Items]
Number of aircraft available for use			126
Segment revenue	50.00%	49.00%	51.00%	51.00%
Oil and Gas [Member] | Minimum [Member] | Major Customer [Member]
Segment Reporting Information [Line Items]
Working period with major customers			30 years
Oil and Gas [Member] | Minimum [Member] | ENI Petroleum [Member]
Segment Reporting Information [Line Items]
Working period with major customers			15 years
Air Medical [Member]
Segment Reporting Information [Line Items]
Segment revenue	47.00%	47.00%	45.00%	45.00%
Number of aircraft assigned			105
Number of states in which company operates aircrafts | States			18
Locations in which company operates Aircrafts | Location			72
Technical Services [Member]
Segment Reporting Information [Line Items]
Segment revenue	3.00%	4.00%	4.00%	4.00%

X

- Definition

Locations in which company operates aircrafts.

+ References

No definition available.

+ Details

Name:	phii_LocationsInWhichCompanyOperatesAircrafts
Namespace Prefix:	phii_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of aircraft available for use.

+ References

No definition available.

+ Details

Name:	phii_NumberOfAircraftAvailableForUse
Namespace Prefix:	phii_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number Of Aircrafts Assigned

+ References

No definition available.

+ Details

Name:	phii_NumberOfAircraftsAssigned
Namespace Prefix:	phii_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of operating states.

+ References

No definition available.

+ Details

Name:	phii_NumberOfOperatingStates
Namespace Prefix:	phii_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of revenue.

+ References

No definition available.

+ Details

Name:	phii_PercentageOfRevenue
Namespace Prefix:	phii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Term of contract.

+ References

No definition available.

+ Details

Name:	phii_TermOfContract
Namespace Prefix:	phii_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Working period with major customers.

+ References

No definition available.

+ Details

Name:	phii_WorkingPeriodWithMajorCustomers
Namespace Prefix:	phii_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

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

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_HealthCareOrganizationRevenueSourcesAxis=phii_HospitalsContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorCustomersAxis=phii_FixedTermCustomerContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorCustomersAxis=phii_ContractedCustomersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

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

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=phii_OilAndGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorCustomersAxis=phii_MajorCustomerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorCustomersAxis=phii_EniPetroleumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=phii_AirMedicalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=phii_TechnicalServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: