Basis of presentation and accounting policies - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Total revenues	$ 675,045	$ 710,363	$ 1,355,094	$ 1,424,615
Distribution
Disaggregation of Revenue [Line Items]
Total revenues	369,577	371,204	749,133	751,707
Advertising & Marketing Services
Disaggregation of Revenue [Line Items]
Total revenues	287,856	298,529	574,253	594,638
Political
Disaggregation of Revenue [Line Items]
Total revenues	8,192	31,643	11,808	59,471
Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 9,420	$ 8,987	$ 19,900	$ 18,799