Earnings per share - Reconciliation of Numerator and Denominator of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Numerator:
Net income attributable to common shareholders	$ 238,673	$ 187,084	$ 690,107	$ 565,044
Denominator:
Basic - weighted average common shares (in shares)	133,232,378	134,809,610	133,410,622	135,675,823
Increase in weighted average common shares from dilutive effect of equity-based awards (in shares)	2,870,596	1,743,159	2,116,573	1,636,025
Diluted - weighted average common shares, assuming exercise of equity-based awards (in shares)	136,102,974	136,552,769	135,527,195	137,311,848
Basic (in usd per share)	$ 1.79	$ 1.39	$ 5.17	$ 4.16
Diluted (in usd per share)	$ 1.75	$ 1.37	$ 5.09	$ 4.12