DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Narrative) (Details)	May 31, 2018 item
DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES [Abstract]
Number of subsidiaries exposed to foreign currency and interest rate cash flow	3

Number Of Subsidiaries, Exposed To Foreign Currency And Interest Rate Cash Flow

No definition available.

Name:	psmt_NumberOfSubsidiariesExposedToForeignCurrencyAndInterestRateCashFlow
Namespace Prefix:	psmt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant