Subsequent event (unaudited) - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended
Aug. 19, 2019	Jun. 30, 2019
Subsequent Event [Line Items]
Future minimum lease payments		$ 13,759
Discontinued Operations, Disposed of by Sale \| Ad Business
Subsequent Event [Line Items]
Percentage of consolidated total assets		5.00%
Percentage of consolidated total liabilities		1.00%
Discontinued Operations, Disposed of by Sale \| Ad Business \| Subsequent Event
Subsequent Event [Line Items]
Percentage of ownership interest received	14.50%
Future minimum lease payments	$ 1,400

Disposal Group, Including Discontinued Operation, Assets, Percentage

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- Definition

Disposal Group, Including Discontinued Operation, Consideration, Percentage Ownership Received

+ References

No definition available.

+ Details

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- Definition

Disposal Group, Including Discontinued Operation, Liabilities, Percentage

+ References

No definition available.

+ Details

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- Definition

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
-Section 55
-Paragraph 40
-Subparagraph (Note 3)
-URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697

+ Details

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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