Fair value measurements (Details 4) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Fair value, balance sheet grouping [Line Items]
Long-term debt	$ 2,847,068	$ 2,841,425	$ 2,747,763
Carrying amount
Fair value, balance sheet grouping [Line Items]
Long-term debt	2,847,068	2,841,425	2,747,763
Fair value
Fair value, balance sheet grouping [Line Items]
Long-term debt, fair value	$ 2,535,125	$ 2,469,625	$ 2,755,041