Leases - Weighted average lease term and discount rate (Details)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases
Weighted-average remaining lease term - finance leases (years)	3 years	24 years 4 months 24 days	27 years 8 months 12 days
Weighted-average remaining lease term - operating leases (years)	7 years 3 months 18 days	8 years 2 months 12 days	8 years 4 months 24 days
Weighted-average discount rate - finance leases	2.30%	4.50%	4.70%
Weighted-average discount rate - operating leases	5.20%	5.30%	5.20%