Stockholders' equity - Common stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2023		Sep. 30, 2022		Sep. 30, 2023		Sep. 30, 2022		Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Stockholders Equity Note [Line Items]
Stockholders' equity	$ 4,457,608		$ 3,674,838		$ 4,457,608		$ 3,674,838		$ 4,565,009	$ 4,093,425	$ 4,293,349	$ 5,969,397
Cash dividends	$ 39,675	[1]	$ 39,973	[1]	$ 118,924	[2]	$ 124,168	[2]
Dividends Declared per Common Share	$ 0.55		$ 0.55		$ 1.65		$ 1.65
Dividend payable, to be paid date					Oct. 02, 2023
Dividends payable, record date					Sep. 08, 2023

[1] Dividends declared per common share during the quarter   ended September 30, 2023 - $ 0.55   (2022 - $ 0.55 ).

[2] Dividends declared per common share during the nine months   ended September 30, 2023 - $ 1.65   (2022 - $ 1.65 ).