Income taxes - Schedule of Deferred Tax Liabilities and Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax liabilities
Accelerated amortization of deductible intangibles	$ 567,009	$ 561,741
Accelerated depreciation	59,558	65,247
Right-of-use assets for operating leases	15,770	18,361
Other	4,097	4,024
Total deferred tax liabilities	646,434	649,373
Deferred tax assets
Accrued compensation costs	23,081	22,450
Pension and post-retirement medical and life	17,804	18,839
Loss carryforwards	15,416	16,435
Operating lease liabilities	16,656	19,443
Other	18,065	18,988
Total deferred tax assets	91,022	96,155
Deferred tax asset valuation allowance	23,801	25,001	$ 26,339	$ 41,929
Total net deferred tax liabilities	$ 579,213	$ 578,219