Basis of presentation, terminated merger agreement and accounting policies - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenues	$ 713,243	$ 803,111	$ 2,185,076	$ 2,362,115
Subscription
Disaggregation of Revenue [Line Items]
Total revenues	377,891	377,368	1,188,297	1,158,101
Advertising & Marketing Services
Disaggregation of Revenue [Line Items]
Total revenues	312,413	320,764	937,984	1,010,490
Political
Disaggregation of Revenue [Line Items]
Total revenues	11,643	92,904	22,925	161,727
Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 11,296	$ 12,075	$ 35,870	$ 31,797