Earnings per share - Computation of basic and diluted earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income attributable to common shareholders	$ 321,409	$ 338,898
Denominator:
Basic - weighted average common shares (in shares)	128,707,745	128,463,992
Increase in weighted average common shares from dilutive effect of equity-based awards (in shares)	1,586,478	1,666,084
Diluted - weighted average common shares, assuming exercise of equity-based awards (in shares)	130,294,223	130,130,076
Basic earnings per share (in USD per share)	$ 2.50	$ 2.64
Diluted earnings per share (in USD per share)	$ 2.47	$ 2.60