XML 56 R45.htm IDEA: XBRL DOCUMENT
v3.20.2

Partners' Capital and Distributions - Additional Information (Detail) | 9 Months Ended
--- | ---
Sep. 30, 2020
Partners Capital Notes [Abstract] |
Period of cash distribution to shareholders | 45 days

X
- Definition Period of distribution of cash to shareholders. + References No definition available. + Details
Name: | hesm_PeriodOfDistributionOfCashToShareholders
Namespace Prefix: | hesm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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