Inventories and natural gas in storage (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Inventory Disclosure [Abstract]
Aggregates held for resale	$ 207,564	$ 199,110	$ 195,489
Asphalt oil	101,271	68,609	93,816
Materials and supplies	45,310	40,056	35,967
Merchandise for resale	42,603	40,296	33,393
Natural gas in storage (current)	8,662	22,533	10,801
Other	20,424	16,921	10,850
Total	425,834	387,525	380,316
Natural gas in storage noncurrent	$ 47,400	$ 47,500	$ 47,500