Stockholders' equity - Common stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022	Jun. 30, 2021		Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Stockholders Equity Note
Stockholders' equity	$ 4,293,349		$ 5,814,614		$ 4,293,349	$ 5,814,614		$ 4,671,246	$ 5,969,397	$ 5,897,559	$ 6,028,687
Cash dividends	$ 42,121	[1]	$ 36,294	[1]	$ 84,195	$ 70,048	[1],[2]
Dividends Declared per Common Share	$ 0.55		$ 0.45		$ 1.10	$ 0.85
Dividend payable, to be paid date					Jul. 01, 2022
Dividends payable, record date					Jun. 02, 2022

[1] Dividends declared per common share during the quarter ended June 30, 2022 - $0.55 (2021 - $0.45).

[2] Dividends declared per common share during the six months ended June 30, 2022 - $1.10 (2021 - $0.85).