Description of the business and summary of significant accounting policies - Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash paid for amounts included in the measurement of lease liabilities
Finance lease cost amortization of right-of-use assets	$ 64,698	$ 28,915
Interest expense on finance lease liabilities	34,940	23,317
Operating lease cost	92,763	18,331
Total lease costs	192,401	70,563
Operating cash flows from finance leases	(33,080)	(23,317)
Operating cash flows from operating leases	(93,924)	(18,836)
Financing cash flows from finance leases	(77,362)	(45,472)	$ (23,054)
Right-of-use assets obtained in exchange for new finance lease liabilities	232,468	107,875
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 13,682	$ 11,168
Weighted-average remaining lease term - finance leases (in years)	11 years 6 months	13 years 6 months
Weighted-average remaining lease term - operating leases (in years)	12 years 2 months 12 days	16 years 7 months 6 days
Weighted-average discount rate - finance leases	7.60%	8.60%
Weighted-average discount rate - operating leases	8.10%	5.40%
Finance leases-fiber lease agreements
Initial terms	20 years
Additional finance lease future payments due	$ 242,800
Future minimum payments (principal and interest) under these finance leases
2024	100,357
2025	95,370
2026	91,955
2027	41,469
2028	40,198
Thereafter	382,361
Total minimum lease obligations	751,710
Less-amounts representing interest	(267,195)
Present value of minimum lease obligations	484,515
Current maturities	(64,594)	$ (17,182)
Finance lease obligations, net of current maturities	419,921	287,044
Future minimum payments under these operating lease agreements
2024	79,272
2025	62,443
2026	57,600
2027	51,511
2028	48,154
Thereafter	328,298
Total minimum lease obligations	627,278
Less-amounts representing interest	(229,221)
Present value of minimum lease obligations	398,057
Current maturities	(67,962)	(12,005)
Lease obligations, net of current maturities	$ 330,095	$ 94,587
Minimum
Finance leases-fiber lease agreements
Initial terms	15 years
Maximum
Finance leases-fiber lease agreements
Initial terms	20 years