Stockholders' equity - Common stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2022		Sep. 30, 2021		Sep. 30, 2022	Sep. 30, 2021		Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Stockholders Equity Note
Stockholders' equity	$ 3,674,838		$ 5,982,971		$ 3,674,838	$ 5,982,971		$ 4,293,349	$ 5,969,397	$ 5,814,614	$ 6,028,687
Cash dividends	$ 39,973	[1]	$ 36,306	[2]	$ 124,168	$ 106,354	[2],[3]
Dividends Declared per Common Share	$ 0.55		$ 0.45		$ 1.65	$ 1.30
Dividend payable, to be paid date					Oct. 03, 2022
Dividends payable, record date					Sep. 07, 2022

[1] During July 2022, the Corporation completed a $400 million accelerated share repurchase transaction with respect to its common stock. During August 2022, the Corporation entered into a $231 million accelerated share repurchase transaction with respect to its common stock. Both were accounted for as treasury stock transactions. Refer to Note 18 for additional information.

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

[3] Dividends declared per common share during the nine months ended September 30, 2022 - $1.65 (2021 - $1.30).