v3.7.0.1

Investment in Variable Interest Entity and Other Investments and Affiliates - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2017	Jun. 30, 2016
PHI Century Limited [Member]
Variable Interest Entity [Line Items]
Investment in the common stock	49.00%		49.00%	49.00%
Earnings (loss) in equity of unconsolidated affiliate	$ 0.1		$ (0.9)	$ 0.1
Trade receivables	2.4	$ 2.0	2.4
Other assets	0.4	$ 0.2	$ 0.4
PHIC's date of incorporation			May 26, 2011
PHI-HNZ Australia Ltd [Member]
Variable Interest Entity [Line Items]
Investment in the common stock		50.00%
Earnings (loss) in equity of unconsolidated affiliate	$ 1.1		$ 1.1
HNZ Group, Inc. [Member] | PHI-HNZ Australia Ltd [Member]
Variable Interest Entity [Line Items]
Investment in the common stock		50.00%

X

- Definition

Equity In Earnings (Loss) Of Unconsolidated Affiliates

+ References

No definition available.

+ Details

Name:	phii_EquityInEarningsLossOfUnconsolidatedAffiliates
Namespace Prefix:	phii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Investment in variable interest entity.

+ References

No definition available.

+ Details

Name:	phii_InvestmentInVariableInterestEntity
Namespace Prefix:	phii_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Trade receivables.

+ References

No definition available.

+ Details

Name:	phii_TradeReceivables
Namespace Prefix:	phii_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

X

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=64801991&loc=SL6759159-111685

+ Details

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

X

- Definition

Date the relationship between reporting entity and the Variable Interest Entity (VIE) began, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=64801991&loc=d3e5747-111685

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=64801991&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityQualitativeOrQuantitativeInformationDateInvolvementBegan1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=phii_PhiCenturyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=phii_PHIHNZAustraliaLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CounterpartyNameAxis=phii_HNZGroupInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: