Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Name:	us-gaap_GoodwillImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Summary of business and significant accounting policies - Goodwill (Details) $ in Thousands	12 Months Ended
	Jun. 30, 2020 USD ($) reporting_unit	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)
Goodwill [Line Items]
Number of reporting units \| reporting_unit	3
Impairment	$ 0	$ 0	$ 2,666
Goodwill	$ 14,300
Advertising Segment
Goodwill [Line Items]
Impairment		$ 2,600
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Goodwill [Line Items]
Impairment			$ 2,700