Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 01, 2019
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	PHII
Entity Registrant Name	PHI INC
Entity Central Index Key	0000350403
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Voting Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		2,905,757
Non-Voting Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		12,919,681