Stockholders' equity - Common stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023		Jun. 30, 2022		Jun. 30, 2023		Jun. 30, 2022		Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Stockholders Equity Note [Line Items]
Stockholders' equity	$ 4,565,009		$ 4,293,349		$ 4,565,009		$ 4,293,349		$ 4,470,725	$ 4,093,425	$ 4,671,246	$ 5,969,397
Cash dividends	$ 39,663	[1]	$ 42,121	[1]	$ 79,249	[2]	$ 84,195	[2]
Dividends Declared per Common Share	$ 0.55		$ 0.55		$ 1.10		$ 1.10
Dividend payable, to be paid date					Jul. 03, 2023
Dividends payable, record date					Jun. 01, 2023

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

[2] Dividends declared per common share during the six months   ended June 30, 2023 - $ 1.10   (2022 - $ 1.10 ).