Cash flow information (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Supplemental Cash Flow Information [Abstract]
Interest, net*	$ 50,294,000	$ 45,870,000
Income taxes paid, net	16,520,000	46,734,000
AFUDC borrowed	1,300,000	816,000
Right-of-use assets obtained in exchange for new operating lease liabilities	18,907,000	17,224,000	$ 55,987,000
Property, plant and equipment additions in accounts payable	46,295,000	31,886,000	57,605,000
Debt assumed in connection with a business combination	$ 0	$ 0	$ 10,000