Earnings per share - Computation of basic and diluted earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income attributable to common shareholders	$ 447,306	$ 204,474	$ 768,715	$ 543,372
Denominator:
Basic - weighted average common shares (in shares)	129,013,781	128,396,933	128,860,763	128,430,463
Increase in weighted average common shares from dilutive effect of equity-based awards (in shares)	2,061,874	2,098,448	1,621,801	1,723,616
Diluted - weighted average common shares, assuming exercise of equity-based awards (in shares)	131,075,655	130,495,381	130,482,564	130,154,079
Basic earnings per share (in USD per share)	$ 3.47	$ 1.59	$ 5.97	$ 4.23
Diluted earnings per share (in USD per share)	$ 3.41	$ 1.57	$ 5.89	$ 4.17