Income taxes - Schedule of Deferred Tax Liabilities and Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred tax liabilities
Accelerated amortization of deductible intangibles	$ 540,260	$ 534,438
Accelerated depreciation	67,278	67,697
Right-of-use assets for operating leases	19,467	21,648
Other	4,183	3,792
Total deferred tax liabilities	631,188	627,575
Deferred tax assets
Accrued compensation costs	23,439	24,147
Pension and post-retirement medical and life	20,775	17,400
Loss carryforwards	12,537	31,841
Operating lease liabilities	20,403	22,582
Other	24,242	25,160
Total deferred tax assets	101,396	121,130
Deferred tax asset valuation allowance	26,339	41,929	$ 43,467	$ 45,661
Total net deferred tax liabilities	$ 556,131	$ 548,374