Earnings Per Share - Computation of earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net income attributable to common shareholders									$ 1,060,801	$ 983,412	$ 806,840
Denominator:
Basic - weighted-average common shares (in shares)									133,004,613	133,377,547	135,353,321
Increase in weighted-average common shares from dilutive effect of equity-based awards (in shares)									2,422,221	2,182,217	1,558,369
Diluted - weighted-average common shares, assuming exercise of stock-based awards (in shares)									135,426,834	135,559,764	136,911,690
Basic earnings per share (in USD per share)									$ 7.98	$ 7.37	$ 5.96
Diluted earnings per share (in USD per share)	$ 2.62	$ 2.70	$ 0.41	$ 2.10	$ 2.15	$ 1.75	$ 1.78	$ 1.55	$ 7.83	$ 7.25	$ 5.89