Shareholders' equity - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 3,071,722
Other comprehensive income (loss), before reclassifications	1,769	$ (16,211)	$ 19,287
Amounts reclassified from AOCL	4,154	(12,106)	4,573
Ending Balance	2,704,872	3,071,722
Equity method investments	16,195	17,003
CareerBuilder Investment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity method investments	0
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(125,533)	(97,216)	(121,076)
Ending Balance	(119,610)	(125,533)	(97,216)
Retirement Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(126,065)	(113,090)	(120,979)
Other comprehensive income (loss), before reclassifications	1,769	(16,288)	3,316
Amounts reclassified from AOCL	4,154	3,313	4,573
Ending Balance	(120,142)	(126,065)	(113,090)
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	532	455	(97)
Other comprehensive income (loss), before reclassifications	0	77	552
Amounts reclassified from AOCL	0	0	0
Ending Balance	532	532	455
Available-For-Sale Investment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 0	15,419	0
Other comprehensive income (loss), before reclassifications		0	15,419
Amounts reclassified from AOCL		(15,419)	0
Ending Balance		$ 0	$ 15,419