v3.5.0.2

Stock-Based Compensation - Summary of Share Based Compensation Expense (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015
Stock-based compensation expense: |  |  |  |
Total stock-based compensation expense | $ 1,406 | $ 1,640 | $ 2,896 | $ 3,359
Time-based Restricted Units [Member] |  |  |  |
Stock-based compensation expense: |  |  |  |
Total stock-based compensation expense | 597 | 571 | 1,216 | 1,208
Performance-based Restricted Units [Member] |  |  |  |
Stock-based compensation expense: |  |  |  |
Total stock-based compensation expense | $ 809 | $ 1,069 | $ 1,680 | $ 2,151

X
- Definition The noncash expense that represents the cost of restricted stock or unit distributed to employees as compensation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 + Details
Name: | us-gaap_RestrictedStockExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=phii_TimeBasedAwardsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=phii_PerformanceBasedAwardsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |