Goodwill and intangible assets - Indefinite Lived Net Balance (Details) $ in Thousands	Jun. 30, 2016 USD ($)
Changes in the goodwill
Net balance at the beginning of the period	$ 164,887
Net balance at the end of the period	164,887
Changes in the goodwill and other indefinite lived intangible assets, on a net basis
Net balance at the beginning of the period	222,929
Net balance at the end of the period	222,929
Broadcast license
Changes in other indefinite-lived intangible assets
Net balance at the beginning of the period	41,356
Net balance at the end of the period	41,356
Brands
Changes in other indefinite-lived intangible assets
Net balance at the beginning of the period	15,986
Net balance at the end of the period	15,986
Other intangibles
Changes in other indefinite-lived intangible assets
Net balance at the beginning of the period	700
Net balance at the end of the period	$ 700