Stockholders' equity - Warrants (Details). shares in Millions	9 Months Ended
Sep. 30, 2018 shares
Stockholders' equity
Number of warrants expired	12.1

Represents the number of warrants expired during the period.

No definition available.

Name:	hmtv_ClassOfWarrantOrRightExpired
Namespace Prefix:	hmtv_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration