Share-based compensation and employee benefit plans - Information about options outstanding and exercisable (Details)	12 Months Ended
	Dec. 31, 2021 $ / shares shares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options outstanding (in shares) | shares	7,087,095
Options outstanding, weighted average exercise price (in dollars per share)	$ 12.61
Options outstanding, remaining contractual life	2 years
Options exercisable (in shares) | shares	6,098,733
Options exercisable, weighted average exercise price (in dollars per share)	$ 12.67
$9.83 - $10.89
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	9.83
Upper range limit (in dollars per share)	$ 10.89
Options outstanding (in shares) | shares	4,663,843
Options outstanding, weighted average exercise price (in dollars per share)	$ 10.02
Options outstanding, remaining contractual life	2 years 1 month 6 days
Options exercisable (in shares) | shares	4,075,481
Options exercisable, weighted average exercise price (in dollars per share)	$ 9.97
$15.00 - $16.89
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	15.00
Upper range limit (in dollars per share)	$ 16.89
Options outstanding (in shares) | shares	1,446,510
Options outstanding, weighted average exercise price (in dollars per share)	$ 15.63
Options outstanding, remaining contractual life	2 years 10 months 24 days
Options exercisable (in shares) | shares	1,046,510
Options exercisable, weighted average exercise price (in dollars per share)	$ 15.87
$20.00 - $25.05
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	20.00
Upper range limit (in dollars per share)	$ 25.05
Options outstanding (in shares) | shares	976,742
Options outstanding, weighted average exercise price (in dollars per share)	$ 20.50
Options outstanding, remaining contractual life	4 months 24 days
Options exercisable (in shares) | shares	976,742
Options exercisable, weighted average exercise price (in dollars per share)	$ 20.50